United States
Environmental Protection
Agency
Policy, Planning,
and Evaluation
(2126)
EPA230-R-96-009
October T996
Indicators of the Environmental
Impacts of Transportation
Highway, Rail, Aviation, and Maritime Transport
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FOREWORD
This document presents quantitative national estimates of the magnitude of transportation's impacts
on the natural environment. It is the most comprehensive compilation of environmental and
transportation data to date. This document addresses all primary modes of transportation (highway,
rail, aviation, and maritime transport) and all environmental media (air, water, and land resources),
and covers the full "life-cycle " of transportation, from construction of infrastructure and manufacture
of vehicles to disposal of vehicles and parts. The information presented in this report highlights that
the impacts of transportation are multi-media and extend beyond the air quality impacts of vehicle
travel.
In addition to presenting quantitative data, this report presents a framework for developing-various
types of indicators and for categorizing transportation activities that affect the environment. This
framework is useful for understanding the limitations and uses of different types of indicators and for
identifying existing data gaps. In some cases, where quantified indicators were not available from
existing sources, new indicators were developed for this report. In other cases, it is clear that
significant gaps in knowledge remain. The report concludes with a description of next steps in the
effort to develop and utilize indicators of the environmental impacts of transportation!
The development of this report involved cooperative work between EPA and DOT/BTS in collecting
data, and addresses issues on which these and other agencies can continue to collaborate to develop
tools for measuring and modeling impacts. This report was prepared under contract for the United
States Environmental Protection Agency, Office of Policy, Planning, and Evaluation by Mark
Corrales, Michael Grant, and Evelyn Chan of Apogee Research, Inc.
This report is part of a series on transportation and the environment issued by the Office of Policy,
Planning, and Evaluation. Additional information can be obtained by calling 202-260-4034.
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TABLE OF CONTENTS
EXECUTIVE SUMMARY...,
.... 1
INTRODUCTION AND PURPOSE. ......................... .. .......................................... . ............. ., ...... . ........... . ........ j
ORGANIZATION OF THIS REPORT ...................... ,. .......... . [[[ . ..... i
STUDY APPROACH ... ............................ 1 ................ '...„ .......................................... . ......................... . ............ a
WHAT INDICATORS CAN AND CANNOT PROVIDE..... .......... . ..................... . .............................. ; ............ m
SELECTING APPROPRIATE INDICATORS ....... . .......... ................................ ! .............................................. iv
CATEGORIZING THE ENVIRONMENTAL IMPACTS OF TRANSPORTATION. ....................................... vii
. THE INDICATORS FOR HIGHWAY, RAIL, AVIATION, AND MARITIME TRANSPORTATION. ............. vizz
NEXT STEPS .................... .. .................................... .. .................... . ...................................... .
I. STUDY APPROACH ________________________________________________________ . _______________________________________________ . _________________ .„ _______ ....i
INTRODUCTION AND PURPOSE. ........... . ................................................ ; ..................... . ............................. j
ORGANIZATION OF THIS REPORT [[[ . [[[ 1
PRIOR AND RELATED EFFORTS.. ................................ 1 [[[ 3
SCOPE OF STUDY .............. . ................... . .......... . ......... . ............... ; ..................................... . ........... ; ............... 5
PRODUCTS OF THIS STUDY. ............................... . ............................ . ....................... .... ............................... 7
LIMITATIONS OF STUDY. [[[ . ...... . ................ . ................................................. 7
H. WHAT INDICATORS CAN AND CANNOT PROVIDE ___________ . ____________ ..... ___________________________________ ....... _____ 9
THE LIMITATIONS OF INDICATORS. .............................. .. [[[ ...9
HOW INDICATORS CAN BE USEFUL ........... . .......... ..... ................. . ......................................... . ................. JJ
HI. SELECTING APPROPRIATE INDICATORS _______________ . _____________________________________________________________ . _______ ....13
COMMONLY CITED "INDICATORS" HAVE LIMITATIONS ................... . ......... . ......... ." .................. . ......... 13
FRAMEWORK -HOW TO DESIGN INDICATORS: ............................ . .............. .'. ..................... . ........ • ........ 15
WHAT IS AN IDEAL INDICATOR? .................................................. . ...... . .............. , ..................................... 20
AVAILABLE INDICATORS ....... . [[[ 23
DATA GAPS [[[ ; ............... 23
TV. CATEGORIZING THE ENVIRONMENTAL IMPACTS OF TRANSPORTATION __________________________ 27
FIVE BASIC ACTIVITIES CAUSING ENVIRONMENTAL IMPACTS ..... ......... .. ........... '...... ........................ 27
DETAILED LIST OF ACTIVITIES CAUSING ENVIRONMENTAL IMPACTS ............ . ............................... 28
V. THE INDICATORS ________________ ... _____ . ____________________________________________ .. ________________________________________________________________ 33
HIGHWAY ENVIRONMENTAL INDICATORS 35
•HOW EACH IMPACT IS PRESENTED IN THIS SECTION. [[[ 35
1. ROAD CONSTRUCTION AND MAINTENANCE ..................... ..... ............................ : .............................. 41
2. MOTOR VEHICLE AND PARTS MANUFACTURE [[[ . ........ : ............. 57
3. ROAD VEHICLE TRAVEL ............................... .......... . [[[ ...... ............... 63
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4. RAIL CAR MAINTENANCE AND SUPPORT. 777
5. DISPOSAL OF RAIL CARS AND PARTS 727
AVIATION ENVIRONMENTAL INDICATORS • 123
HOW EACH IMPACT IS PRESENTED IN THIS SECTION. 723
/. AIRPORT CONSTRUCTION, MAINTENANCE, AND EXPANSION 727
2. AIRCRAFT AND PARTS MANUFACTURE. 733
3. AVIATION TRAVEL , 737
4. AIRPORT OPERATION 757
5. DISPOSAL OF AIRCRAFT AND PARTS 755
MARITIME ENVIRONMENTAL INDICATORS 157
HOW EACH IMPACT IS PRESENTED IN THIS SECTION. ; 757
1. CONSTRUCTION AND MAINTENANCE OF NAVIGATION IMPROVEMENTS. 767
2. MANUFACTURE OF MARITIME VESSELS AND PARTS 769
3. MARITIME TRAVEL 773
4. MARITIME VESSEL MAINTENANCE AND SUPPORT 789
5. DISPOSAL OF MARITIME VESSELS AND PARTS 793
VI. NEXT STEPS . 195
COLLECT RAW DATA OR LOCAL DATA WHERE NEEDED 795
DEVELOP NEW ESTIMATES OF CERTAIN IMPACTS 795
DESCRIBE EFFECTIVENESS OF MITIGATION OPTIONS 796
CONSIDER IMPACTS NOT LISTED HERE. 796
SETUP ONGOING, CONSISTENT USE OF INDICATORS 796
REGULARLY UPDATE OUTDATED, ONE-TIME ESTIMATES 797
CONDUCT POLICY ANALYSIS 797
PROVIDE STATE AND LOCAL TOOLS 79S
BIBLIOGRAPHY .....199
>
APPENDIX A. INFRASTRUCTURE AND TRAVEL MEASURES A-l
MODE: HIGHWAY A-2
INFRASTRUCTURE. < A-2
TRAVEL A-6
MODE: RAIL A-13
INFRASTRUCTURE. A-73
TRAVEL A-15
MODE: AVIATION A-18
INFRASTRUCTURE A-18
TRAVEL A-20
MODE: MARITIME A-29
INFRASTRUCTURE. A-29
TRAVEL , ,...A-30
APPENDIX B. ADDITIONAL STATISTICS ON IMPACTS B-l
HEALTH EFFECTS B-l
TOXIC RELEASES B-3
MONETIZED VALUES B-4
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Executive Summary
EXECUTIVE SUMMARY
INTRODUCTION AND PURPOSE
In early 1995, the Environmental Protection Agency (EPA) initiated a study to develop environmental
indicators for the transportation sector. The purpose of this report is the following:
1. Develop a logical framework for thinking about indicators
2. Identify and categorize the full range of environmental impacts of transportation
3. Develop indicators of these impacts
4. Quantify the impacts at the national level, using the indicators
5. Assess data gaps and recommend next steps
This report presents the most comprehensive compilation of environmental and transportation data to
date. The term "indicators" is used throughout this report to refer to quantitative estimates of the
magnitude or severity of environmental impacts of transportation. These indicators may be based on
either measurements or modeling and may refer to either historical or projected estimates.
This report addresses all four primary modes of transportation:
* Highway1
4 Rail ; •
* Aviation .
* Maritime2 ' • '
In addition, this report addresses all environmental media—air, water, and land resources. It covers
the full "life-cycle" of transportation, from construction of infrastructure and manufacture of vehicles
to disposal of vehicles and parts.
In addition to presenting quantitative data, this report presents a valuable framework for developing
various types of indicators and categorizing transportation activities affecting the environment. It also
identifies existing data gaps. The report concludes with a description of next steps in the effort to
develop and utilize indicators of the environmental impacts of transportation.
ORGANIZATION OF THIS REPORT
The report is organized in the following sections:
4 Study approach
* What indicators can and cannot provide
4 Selecting appropriate indicators
4 Categorizing the environmental impacts of transportation
4 Indicators for highway, rail, aviation, and maritime transportation
In this report, the term "highway" is used to refer to mobile sources of travel on all roads, not only those in the
National Highway System. •
2 In this report, the term "maritime" is used to refer to all mobile sources of travel on water, including ocean-
going vessels, inland barges, and recreational boats.
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Indicators of the Environmental Impacts of Transportation
4 Next steps
4 Bibliography
4 Appendices on infrastructure and travel measures and additional statistics
Each is summarized briefly below.
STUDY APPROACH
This study may be viewed in the context of numerous related efforts to develop and utilize
environmental indicators. Other such efforts generally have been limited, however, in that they have
examined a smaller number of environmental issues ( only air quality) or have focused on total
environmental change rather than isolating transportation's share of that change.
This study is uniquely broad, since it covers several modes of transportation and all environmental
media. It is an attempt to address a wide range of issues at a summary level.
This study has some important limitations as well:
LIMITATIONS OF THIS STUDY
4 It provides only national estimates of impact, not local details.
4 It is not a textbook on the environmental issues, although it describes each environmental
impact briefly.
4 It de-emphasizes the impacts of related infrastructure ( gas stations, the petroleum industry,
etc).
4 Aesthetics/visual impacts, historic preservation, nonrenewable energy use, and social and
community impacts are not included.
4 Impacts of related development are not included here (impacts of new housing enabled by
road construction).
4 The benefits of travel are outside the scope of this study, although they should be weighed
along with the environmental impacts of travel in a broader policy analysis.
The study's scope was limited to providing the following products, which correspond to the goals set
out initially:
PRODUCTS OF TfflS STUDY
1. Framework for indicators
2. ' Categories including all impacts
3. Indicators
4. Quantitative data
5. List of data gaps and recommended next steps
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Executive Summary
WHAT INDICATORS CAN AND CANNOT PROVIDE
In using indicators, it is important to keep in mind that they can be misapplied, and that care should be
taken to consider what indicators can and cannot provide.
WHAT INDICATORS CANNOT OR SHOULD NOT DO
* Isolate effects of individual regulations
Indicators may show improvement in a certain area (e.g., mobile source air emissions and
air quality) but generally will not describe the root causes underlying that
improvement. In other words, they may show the net results but not why the situation
improved. For example, indicators may show falling air emissions, but these could
result either from policy-driven per-mile emissions reductions or from reduced travel
.due to an economic downturn or rising fuel prices.
4 Provide a full economic analysis
In particular, indicators do not provide information about the benefits of travel and related
activities. For example, deicing salt application has significant environmental
impacts but it also has enormous benefits in allowing travel and saving lives during
storms. Also, indicators say nothing about the costs of policies that might alleviate
environmental impacts. Some solutions may be quite costly, and these costs should
be balanced against the environmental impacts.
4 Define acceptable levels of impact or rates qf progress
Indicators may describe objectively the amount of impact or rate of progress, but policy
decisions must be made subjectively about whether a given impact or rate of progress
is acceptable. ,
4 Set true priorities
Indicators of environmental impact alone should not be used for setting priorities for
regulatory action. The cost-effectiveness of policy options should also be considered.
This combines costs and benefits, whereas indicators of environmental impact
describe only potential benefits of policies.
As long as these limitations are understood, indicators can be extremely useful in transportation and
environmental policy discussions.
WHAT INDICATORS CAN BE USED FOR
4 Provide broad perspective on transportation and environmental issues
4 Encourage, a comprehensive look at all environmental impacts
4 Track progress of policies as a whole
4 Highlight remaining problems '
4 Help set priorities, particularly for research and among issues needing new or improved
policies
4 Educate the public, media-focused offices, and others
4 Feed into economic/policy analysis
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Indicators of the Environmental Impacts of Transportation
SELECTING APPROPRIATE INDICATORS
One important goal of this study was to consider the types of indicators that would be most
appropriate for tracking the environmental impacts of transportation. To do so, we first examined the
limitations of commonly cited indicators and considered what an ideal indicator would look like. A
framework was presented that demonstrates how indicators may be designed to focus on different
stages of the link between transportation and the environment, from outputs to outcomes (see the
graphic entitled "Causes and Effects of Transportation Activities")- Finally, the report highlighted
data gaps that make, the use of ideal indicators impossible at present, but point to areas where research
would be most beneficial (see the graphic entitled "Data Availability").
In the process of de" ling ideal indicators and identifying data gaps, we noted several areas where the
ideal is not available. This report, therefore, describes ideal indicators as long-term objectives
requiring further data collection and modeling. The indicators actually quantified in the report are
often simply measures of emissions or outputs, because data on outcomes were generally unavailable.
In some cases, even emissions or habitat change data were not available, in which case the report cites
measures of activities that lead to those emissions or habitat changes.
Many discussions of the impacts of transportation use activity measures rather than true indicators of
environmental outcomes. For example, many reports cite vehicle-miles traveled (VMT) as an
indicator of transportation's potential impacts on the environment. Such measures are seriously
flawed for the purpose of assessing environmental impacts, however.
LIMITATIONS OF VMT AND OTHER COMMON MEASURES
* Results are more important to track than activities.
* Impacts per VMT or other activity measure vary a great deal by location.
4 Impacts per VMT or other activity measure vary over time.
4 Average impacts are not useful when one should be measuring marginal impacts (the effects
of incremental increases in travel are marginal impacts; there may be thresholds or other
circumstances so that the impact associated with additional VMT differs from the average
impact per VMT).
4 The benefits per passenger-mile traveled (PMT) or per ton-mile are not equal for all modes
and locations.
As stated above, though, VMT and other activity measures may be the only relevant quantitative data
providing perspective on certain impacts. This report refers to activity measures where necessary and
discusses them further in an appendix.
This report also presents a framework for describing different types of indicators, based on the extent
to which they address end results rather than activities. The framework, shown in the flow chart,
suggests that an indicator may be designed to focus on activities (e.g., VMT), outputs such as
emissions and habitat changes (e.g., tons of CO2 emitted or acres paved), or outcomes/end results
(e.g., number of illnesses caused by mobile source pollution). This framework is often used to
emphasize the need for results-oriented measures. Again, this study made clear that such indicators
are generally unavailable at present, and output measures must be used in the short term.
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Executive Summary
We recommend that improved indicators be developed through data collection and modeling efforts,
to reach the long-term goal of designing ideal indicators of transportation's environmental
implications. The characteristics of indicators that should be developed over time are described
below:
THE IDEAL INDICATOR
* Focuses on results (i.e., outcomes, such as number of illnesses caused, not activities or
outputs, such as tons emitted)
* Isolates transportation's share of the impact
+ Provides a useful level of detail to the intended audience
* Is stated in comparable units (allowing comparisons among impacts, modes, etc.)
* Is in meaningful units (i.e., the quantity is compared to a standard or goal)
* Is reasonably certain
These are the traits that should be sought in ongoing development of new indicators. For the purposes
of this study, we have been able to design indicators that meet only some of these criteria. Most
indicators, in this study isolate transportation's share and provide sufficient detail at the national level.
Many are not in comparable units (e.g., dollars) because of the additional analysis required and
uncertainty introduced when dollar terms are used. The units are more meaningful if the quantities
are compared with standards or goals, but such benchmarks are not yet available for most of these
indicators. Additional work is needed to develop ideal indicators.
CATEGORIZING THE ENVIRONMENTAL IMPACTS OF TRANSPORTATION
An important contribution of this study is the relatively comprehensive nature of the list of
environmental impacts. We have quantified a much wider range of impacts than is typically included
in a single study. To do so, we utilized a categorization scheme that groups the impacts logically and
encourages a broad perspective of the environmental implications of transportation. This scheme is
based on grouping impacts by the activities that cause them rather than by environmental media, such
as water and air. The advantage of this approach is that it follows the way data are collected and the
way activities are commonly thought about and addressed in policy discussions. The five basic
activities included are as follows:
BASIC TRANSPORTATION ACTIVITIES AFFECTING THE ENVIRONMENT
1. Infrastructure construction, maintenance, and abandonment (e.g., bujtlding roads)
2. Vehicle and parts manufacture . •
3. Vehicle travel •
4. Vehicle maintenance and support
5. Disposal of used vehicles and parts
Within each of these five broad activities, several individual activities and their impacts are described.
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Indicators of the Environmental Impacts of Transportation
THE INDICATORS FOR HIGHWAY, RAIL, AVIATION, AND MARITIME TRANSPORTATION
This report contains not only a listing of available indicators but also the values of those indicators for (
recent years. The body of the report contains these quantitative data and graphics, while the
indicators are listed in tables below for each of the four modes.
It is important to note two points about what is included in these tables: First, indicators are listed
only where they have been quantified at the national level; if an impact has not been quantified, no
"potential" indicator is listed here. For each specific activity and its impact, the table provides a
summary of the availability of quantitative data for indicators of outcomes, output, and activity.
Second, the tables show only the best indicator for each impact rather than listing alternative types of
indicators. The exceptions are when multiple indicators are needed to address all aspects of an issue
or where some indicators are otherwise insufficient. Although outcome indicators are theoretically the
most desirable type of indicator, actual quantified outcome data are often unavailable or of poor
quality. As a result, output indicators—such as emissions levels—tend to be the most reliable and •
valid measures available in most cases. Activity indicators are presented in these tables when they are
the best available indicators or when outcome and output indicators are not adequate.
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-------
Executive Summary
NEXT STEPS
There are several logical next steps in the effort to develop and utilize indicators of the
environmental impacts of transportation. This study has taken initial steps in presenting a
framework for the design of ideal indicators and a comprehensive list of impacts. It has also
provided quantitative data on various impacts. There are still, however, considerable gaps in the
data and analyses needed to fully describe indicators in this area. Next steps include the
following:
4 Collect raw data or local data where needed
There are several areas in which local or state data exist but have never been aggregated
at the national level. There are other areas in which raw data would have to be collected
for development of indicators. Examples include the following:
4 Wetlands impacts
4 Habitat fragmentation and disruption from all modes
4 Hazardous materials entering the environment
4 Maritime terminal operation releases
4 Emissions during construction and maintenance of infrastructure
4 Leaking underground storage tank (LUST) releases attributable to transportation
4 Scrappage of aircraft, marine vessels, and rail cars/locomotives
4 Develop new estimates of certain impacts
National estimates of certain impacts have not been developed to date. In some cases,
such estimates could be developed without the collection of additional raw data. Existing
or new models could be applied to develop new national estimates of certain
environmental impacts. In particular, new estimates of the following impacts are needed:
4 Emissions from road construction and paving
4 Impacts of and quantities of emissions from aircraft at high altitudes
4 Deicing runoff impacts on water quality
4 Quantities released from spills and leaks at airports
4 Other runoff impacts on water quality
4 Motor vehicle scrappage (tons disposed of, by material)
4 Noise exposure (updated estimates)
4 Roadkill (some data collection may be needed)
At least two types of estimates should be developed:
4 Measures of emissions, loadings, or ambient levels, and
4 Actual health or welfare risks
xvm
-------
Indicators of the Environmental Impacts of Transportation
Describe effectiveness of mitigation options
Various mitigation options, such as noise barriers, runoff detention ponds, and wetlands
mitigation efforts, for example,.have been studied to some extent. It would be useful to
track the effectiveness of such efforts and the extent of their utilization in cases where
more direct, accurate estimates of actual results are difficult to obtain.
Consider impacts not listed here
Environmental damage may be caused by several transportation-related activities not
included in this study:
* Gas stations, including auto repair and maintenance
* Parking facilities (lots and garages)
4 Related land-use development patterns '
* Petroleum industry (transportation's share of these upstream impacts)
* Steel industry (transportation's share of these upstream impacts)
* Chemical industry (transportation's share of these upstream impacts)
Set up ongoing, consistent use of indicators
Implementing the findings and recommendations in this study will require an organized,
broad initiative to begin using a consistent set of indicators. This effort should take into
account the various state, federal, and private efforts to track the environmental impacts
of transportation and use those data in the policy process.
Regularly update outdated, one-time estimates
Several of the indicators in this report have been quantified only once, or only
sporadically in surveys or one-time modeling exercises. These estimates should be
updated regularly. Examples of such outdated or one-time estimates that require updating
include the following:
* Noise exposure (especially for road travel)
* Air toxic emissions during travel
4- Runoff (typical concentrations of pollutants in runoff)
* Use of airport deicing agents '
Conduct policy analysis
Now that this study has compiled data on environmental impacts, and as improved
indicators are developed, they should be used to improve national policy understanding.
This could entail several types of relatively modest studies, which could provide policy-
relevant results.
f Compare across modes, across media, across impacts
* Compare with other environmental issues
• * Consider costs of policies
xix
-------
Executive Summary
Provide state and local tools
Ideally, further work would determine which impacts vary directly with VMT and which
vary based on various other parameters. This work would essentially consist of
developing true models to predict the magnitudes of various impacts, based on inputs
such as VMT, temperature, or other causal factors such as those listed in the report.
Some such models exist, such as the highway runoff predictive model, or noise models,
but they do not exist for very many of these impacts. Also, the models typically require
numerous site-specific inputs that are costly to collect. New models could be developed,
perhaps for screening purposes.
xx
-------
Study Approach
I. STUDY APPROACH
INTRODUCTION AND PURPOSE
In early 1995, the Environmental Protection Agency (EPA) initiated a study to develop environmental
indicators for the transportation sector. The purpose of this report is the following:
1. Develop a logical framework for thinking about indicators
2. Identify and categorize the full range of environmental impacts of transportation
3. Develop-indicators of these impacts ,
4. Quantify the impacts at the national level, using the indicators
•5. Assess data gaps and recommend next steps
This report presents the most comprehensive compilation of environmental and transportation data to •
date. The term "indicators" is used throughout this report to refer to quantitative estimates of the
magnitude or severity of environmental impacts of transportation. These indicators may be based on
either measurements or modeling, and may refer to .either historical or projected estimates.
This report addresses all four primary modes of transportation:
* Highway1
+ Rail
* Aviation
* Maritime2. ' •
In addition, this report addresses all environmental media—air, water, and land resources. It covers
the full "life-cycle" of transportation, from construction of infrastructure and manufacture of vehicles
to disposal of vehicles and parts.
In addition to presenting quantitative data, this report presents a valuable framework for developing
various types of indicators and categorizing transportation activities affecting the environment. It also
identifies existing data gaps. The report concludes with a description of next steps in the effort to
develop and utilize indicators of the environmental impacts of transportation.
ORGANIZATION OF THIS REPORT
The report is organized in the following sections:
I. STUDY APPROACH
This section describes the study's goals and policy context. It also describes
the study's scope and limitations.
1 In this report, the term "highway" is used to refer to mobile sources of travel on all roads, not only those in the
National Highway System..
2 In this report, the term "maritime" is used to refer to all mobile sources of travel on water, including ocean-
going vessels, inland barges, and recreational boats.
-------
Indicators of the Environmental Impacts of Transportation
H. WHAT INDICATORS CAN AND CANNOT PROVIDE
This section clarifies the purpose of developing environmental indicators of
transportation's environmental impacts by describing how such indicators can
and should be used. We emphasize, however, that there are certain types of
analysis for which indicators are insufficient and should be used only with
caution.
ID. SELECTING APPROPRIATE INDICATORS
Many of the "indicators" commonly cited to gauge environmental impacts
have significant limitations. This section discusses those shortcomings. We
then present a framework for thinking about what types of indicators would
be most appropriate. Ideal indicators are contrasted with available ones, and
general data gaps are identified.
IV. CATEGORIZING THE ENVIRONMENTAL IMPACTS OF TRANSPORTATION
Transportation affects the environment in numerous ways. In this section, we
present a scheme for categorizing the full range of activities making up the
"transportation sector" and list the impacts resulting from each.
V. THE INDICATORS
In this section, we present the numbers. For each environmental impact,
indicators are listed, with quantitative estimates. We also describe each
impact briefly, and list the mam causal factors and location-specific variables
that determine the magnitude of the impact in a given location or in a specific
year. This section covers highway, rail, aviation, and maritime indicators.
VI. NEXT STEPS
This section addresses the gaps in the current list of indicators. The need to
collect data and develop estimates of certain impacts. The usefulness of
setting up ongoing, consistent use of indicators is also discussed, along with
the types of policy studies that could be conducted using these indicators.
BIBLIOGRAPHY
Selected references are included.
APPENDIX A. INFRASTRUCTURE AND TRAVEL MEASURES
This appendix provides a discussion of how indicators of infrastructure and
travel activities are relevant to environmental indicators. Quantitative data are
provided.
APPENDIX B. ADDITIONAL STATISTICS ON IMPACTS
This study uncovered a wide range of statistics that were not always ideal as
indicators, but relevant and useful in providing additional perspective on
various environmental impacts. Some of these statistics are provided in this
section.
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Study Approach
PRIOR AND RELATED EFFORTS
We view this study as part of a broad effort among decision makers, scientists, and the public to better
understand and take into account environmental results. It may be helpful, therefore, to place this
report in the context of the various prior and related efforts at developing environmental indicators or
assessing the impacts of transportation.
Performance measurement has gained renewed attention across the public and private sectors in
recent years. Several high profile reports, including the National Performance Review and
Reinventing Government,3 have stressed measuring the value of public programs in terms of the
extent to which they are attaining goals. These reports and related initiatives have spurred further
development and reporting of indicators. New requirements have also increased the attention given to
indicators. OMB Circular A-l 1 requires that performance indicators be included in budget documents,
and ISTEA mandates development and use of performance indicators related to air quality and other
factors for assessment of the effects of the surface transportation system.4
It is clear that numerous types of indicators have been developed to track the effects of government
prograrhs or the status of environmental quality generally. This study differs from most or all of those
efforts because it attempts to discern the environmental impacts of a single "sector". Rather than
measuring the effects of a.program or tracking environmental quality in general, we are attempting to
isolate the effects of the set of activities and infrastructure that constitute the transportation sector.
In this study, we have drawn upon an enormous range of prior literature, including the following
notable efforts:
+ The OECD and others, including some states, have discussed or presented indicators of the
environmental impacts of transportation.5 These studies are useful because they demonstrate
a pragmatic, local perspective or provide insightful discussions of conceptual issues in
indicator design. Most of these reports, however, address a limited range of impacts (e.g.,
only ah" pollution) or offer simple activity-based measures (e.g., tonne-kilometers of
hazardous waste transported).
4 Performance measures for the National Transportation System are being developed by the
U.S. Department of Transportation (DOT), and a recent report mentioned some
environmental measures. The 34-page draft report, however, devoted merely 2 pages to
environmental indicators, addressed a limited range of impacts and modes, and provided no
actual numbers.6 The DOT's Bureau of Transportation Statistics (BTS) has recently been
working on environmental statistics.
3 See National Performance Review 1993. Also see Status Reports under the same name. Also, see Osborne,
David, and Ted Gaebler, Reinventing Government: How Entrepreneurial Spirit is Transforming the Public '
Sector. Addison-Wesley: 1992.
4 Section 6001(b)(3), in Title VI (Research) of the Intermodal Surface Transportation Efficiency Act of 1991.
5 For example, see OECD, 1993; SRI International, 1993 for state efforts; and IndEco Strategic Consulting, Inc.,
1995 for Canadian indicator development.
6 Indicators are suggested in Cambridge Systematics, Inc. 1995b. A companion working paper, Cambridge
Systematics 1995a, classifies environmental measures as "secondary" concerns that should be given less weight
than the "primary" issues of economic and social impacts. This contradicts the Federal Highway Administration's
Environmental Policy Statement (1994) which states, "Social, economic, and environmental issues must be
considered equally...in reaching project decisions."
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Indicators of the Environmental Impacts of Transportation
* The literature on the economic-costs of transportation contains a significant amount of
information on certain impacts, particularly air pollution's effects. Apogee Research's 1994
study, The Costs of Transportation, for example, reviews quantitative estimates of air
pollution costs. These studies, however, generally address a limited range of environmental
impacts and in less depth. Estimates given in dollar terms entail additional uncertainty and
sometimes controversy compared with non-economic measures of these effects.
4 Several detailed reviews of transportation's environmental impacts are available, providing
thorough explanations of these impacts. We have chosen not to duplicate those discussions
in this report. We have, however, drawn upon those reviews. For example, three books,
Highway Pollution, The Environmental Impact of Railways, and Ecological Risks of
Highways, provide useful discussions but few numbers.7
4 Many studies are available which report on transportation's impacts for individual projects,
including Environmental Impact Statements and Reviews (EISs and EIRs),8 as well as
academic papers. These provide a useful perspective on how impacts are determined by
various location-specific parameters.
* Some reports generalize results to the national level but typically address only one impact
(e.g., a review of highway runoff predictive models). These are useful for a more complete
understanding of certain impacts.
In addition to these highly relevant studies, we also drew on other literature that covered
environmental indicators more broadly. S,ome of these provide useful discussions of how indicators
should be designed and point to available data sources. An important limitation to these, it should be
noted, is that they do not isolate the environmental changes that result from a particular set of
activities, such as travel. Some examples of such efforts include the following:
4 Apogee Research recently prepared a 7995 Indicators Report for EPA, a compilation of
readily available environmental indicators organized according to environmental goals, such
as clean water. The report includes graphics and statistical information on dozens of aspects
of environmental quality.
* EPA's Compendium of Selected National Environmental Statistics and Guide to Selected
National Environmental Statistics in the Federal Government are examples of recent efforts
to disseminate data on several environmental media.9
* EPA is engaged in ongoing efforts to develop improved indicators of environmental quality,
focused on results.10 EPA also has a Center for Environmental Statistics in the Office of
Policy, Planning, and Evaluation. EPA is furthermore leading the long-term Environmental
7 Hamilton and Harrison, 1991; Carpenter, 1994; and Atkinson and Cairns in Cairns et al., 1992; respectively.
8 For example, see FAA, 1990; U.S. DOT/FHWA and MD DOT, 1995; or U.S. DOT/FRA, 1994a.
9 EPA databases are available on-line through the EPA web page at "www.epa.gov"
10 For example, see EPA's 1995 report Prospective Indicators for State Use in Performance Partnership
Agreements. Specific offices have initiatives as well: EPA's Office of Water created an Indicators Workgroup.
Also see EPA's annual Accompanying Report of the National Performance Review, in which EPA cited the
commitment to developing measurable environmental goals.
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Study Approach
Monitoring and Assessment Program (EMAP). EPA's 1994 Strategic Plan articulates goals
for the agency and a 1995 report addresses EPA's information resources management.11
* The Council on Environmental Quality (CEQ) has published widely read reports on the state
of the environment for many years.12 In 1991 CEQ convened an Interagency Committee on
Environmental Trends. The Worldwatch Institute issues State of the World reports annually,
with a global focus.13 The United Nations and European Union also have major initiatives to
; collect and disseminate environmental data.14
4 EPA's National Water Quality Inventory reports to Congress15 summarize data from the
states (required by the Clean Water Act Section 305(b)), covering topics such as the
percentage of assessed river-miles meeting certain standards and the share of impairment
attributable to certain broad types of causes (e.g., urban runoff). The Intergovernmental Task
Force on Monitoring Water Quality has issued reports on more detailed measures of
conditions. Federal Status and Trends Programs are coordinated among numerous agencies
and seek a nationwide strategy for monitoring environmental quality.
This study has drawn upon and taken into consideration all of these prior and ongoing efforts related
to indicators and environmental impacts, but it has also attempted to build upon those efforts and go
beyond them.
SCOPE OFSTUDY
MULTIMODAL AND MULTIMEDIA
This study is unique in its attempt to quantify the full range of environmental impacts that result from
transportation. Two features of the study are important. It is both multimodal and multimedia:
4 MULTIMODAL- ALL MODES OF TRANSPORTATION17
* Highway
«• Rail ,
> Aviation • " • .
* Maritime
11 U.S. EPA, 1995h.
Council on Environmental Quality, Environmental Quality.
13 World watch Institute, 1994.
The U.N. has developed a core set of environmental indicators for sustainable development and has asked
member countries to gather data in these common formats. The European Environment Agency, based in
Denmark, issued a 600-page study called the Dobris Assessment, Europe's Environment, covering global and
European data.
1? U.S. EPA, 19.94b.
^Intergovernmental Task Force on Monitoring Water Quality, September 1994.
Transport by pipeline is sometimes included in such listings but is outside the .scope Of mis study. Pipeline does
carry a significant amount of material, however, and could be considered for analysis in a separate effort.
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Indicators of the Environmental Impacts of Transportation
4 MULTIMEDIA- ALL ENVIRONMENTAL MEDIA18 '
4 Air
* Water
4 Waste (solid/hazardous)
* Habitat
WHICH TYPES OF IMPACTS WERE EXCLUDED
Addressing all modes and all media already implies a vast scope. For this reason, we have chosen to
limit the scope somewhat to emphasize the direct, short-run impacts of operating vehicles and the
infrastructure that most directly supports them (e.g., highways, train tracks, airports, and ports). We
have de-emphasized or excluded the indirect, upstream, downstream, and historical impacts. These
emphases are summarized below with some examples of each type of impact.
IMPACTS EMPHASIZED
4 Direct impacts of travel and its key infrastructure (e.g., hazardous materials incidents
during transport, runoff of deicing compounds)
* Short-run variable costs and certain ongoing costs (impacts that are related to the amount
of travel or other activities, such as construction and maintenance, and can be tracked on an
annual basis; e.g., air pollutant emissions from vehicle operation)
IMPACTS DE-EMPHASIZED OR EXCLUDED
* Impacts of other related infrastructure (e.g., auto repair shops, shipyards)
* Certain long-run costs, including some fixed costs (e.g., no analysis of the historical
destruction of wetlands and forests to build existing highways or the environmental benefits
that would accrue if land use reverted to historical uses)
4 Upstream impacts (e.g., some examination of the manufacture of vehicles, but not the raw
inputs into that process, such as the impacts of the steel or chemical industry; very limited
consideration of gasoline/oil refining19)
* Downstream impacts (some consideration of the disposal of tires, waste oil, and vehicles, ,
but not a full analysis of all disposal impacts)
18 Habitat is listed as a separate category, despite the fact that it can be affected by air, water, or waste. "Habitat"
here refers more to physical disruption of habitat through road construction, than to pollution of habitat.
Likewise, waste can enter the air or water and affect habitat but is considered as its own category in this listing.
These distinctions are not essential since these "media" are not used in the report as a major categorization
scheme. Instead, we categorize impacts by activities that cause them, as discussed later.
19 A number of sources provide information on the upstream impacts of fuel extraction, transportation, refining
and distribution. U.S. EPA, 1995c, includes data on toxic releases from the petroleum refining industry; Ross, et
al., 1995, provides information on upstream emissions of CO, HC, and NOX per mile for Model Years 1993,'
2000, and 2010 passenger cars; DeLuchi, 1991, provides data on upstream greenhouse gas emissions (CEU, N2O,
NMOC, CO, NOx, and COi), including emissions from materials manufacture and vehicle assembly, per mile.
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Study Approach
4 Indirect impacts (e.g., no analysis of the effects of industrial or residential development that
arises near new roads/airports, effects on a natural area such as a lake when a road is built
close to it) '
4 Cultural, aesthetic, and some resource depletion issues (No analysis of these impacts. The
focus here is on pollution and habitat disruption. Cultural and aesthetic (e.g., visual)20
impacts are more "social" effects than environmental, as defined here. Nonrenewable
resource depletion (i.e., the use of oil) is not included because it does not damage the
environment per se. We view it as a self-regulating economic phenomenon, where increasing
shortages in oil would drive up prices and encourage more efficient use or a shift to
alternatives. Depletion of living resources, on the other hand, such as forests or wetlands, is
considered here as an impact on habitats.)
PRODUCTS OF THIS STUDY
The study's scope is limited to providing the following products, which correspond to the goals set
out earlier:
1. Framework for, indicators
2. Categories including all impacts
3. Indicators '.
4. Quantitative data
5. List of data gaps
LIMITATIONS OF STUDY
In addition,to'the bounds discussed above, this study has the following limitations:
4 NOT A PRIMER
This study does not provide a full introduction to the nature of each
environmental impact. Primers are available elsewhere which thoroughly
explain these impacts. For a complete explanation of how highways generate
contaminated water runoff, for example, those other sources should be
consulted.
4 NATIONAL ONLY
The study does-not provide indicators or tools that can simply be applied at
the local level to assess the environmental impacts of a single project or for a
given urban area. Instead, national-level estimates are provided of the total
impacts of transportation.
The text does, of course, provide basic introductions to these impacts and references to studies that
can be used in local assessments. .
For information on visual impacts of highway projects, see DOT/FHWA, 1981.
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What Indicators Can and Cannot Provid
II. WHAT INDICATORS CAN AND CANNOT
THE LIMITATIONS OF INDICATORS
Given the current level of interest in the use of indicators and performance measures, there is some
risk that the benefits of indicators could be overemphasized. While very useful, indicators are more a
tool than an answer to all policy questions, and can be misapplied if their limitations are not
understood.
There are several important policy uses to which indicators cannot and should not be applied. They
include the following:
WHAT INDICATORS CANNOT OR SHOULD NOT. DO
4 Isolate effects of individual regulations
* Provide a full economic analysis
4 Define acceptable levels of impact or rates of progress
4 Set true priorities . / '
Each of these limitations is briefly explained below.
INDICATORS CANNOT ISOLATE THE EFFECTS OF INDIVIDUAL REGULATIONS
The indicators presented in this report describe the effects of all existing transportation infrastructure
and activities and cannot isolate the effects that result from a single regulation or even set of
regulations. In other words, the indicators are based on total costs rather than incremental or marginal
' costs of a particular requirement or activity.
When presented with total costs, one may be tempted to divide them by a measure of activity such as
vehicle-miles traveled (VMT) and assume that this average impact is equivalent to a marginal impact.
For example, if one chemical's total impact is 2 billion tons of pollution, the national average is about
1 ton per 1,000 VMT. This does not mean, however, that a policy that reduces VMT by 1,000 would
reduce, emissions by 1 ton. Speeds and many other local factors determine the effectiveness of any
policy. In effect, the indicators represent the total environmental costs of transportation rather than the
incremental or marginal costs of changes in level of activity or infrastructure. This issue is raised
again in the discussion of selecting appropriate indicators. Unfortunately, one cannot accurately
assess the effects of policies using most types of indicators.
INDICATORS CANNOT PROVIDE A FULL ECONOMIC ANALYSIS
Policy decisions must be based on a full range of criteria, including the costs and benefits of various
options. Environmental indicators only describe an upper bound on the potential environmental
benefits of additional policy efforts. They exclude several important pieces of information:
4 Costs of policies/Benefits of travel: The environmental damage from transportation may
constitute a substantial cost to society and the environment, but the costs of solving the
problem may be large as well. Transportation provides great benefits which-may be lost if
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Indicators of the Environmental Impacts of Transportation
policies restrict travel. Some statutes limit the extent to which costs can be considered in
environmental protection decisions (e.g., ambient air quality standards are health-based, and
the Delaney Clause in food and drug law requires protection of health at any cost). It is
widely accepted, however, that costs are an important consideration in governmental
decisions. Indicators provide no information on the cost of addressing an environmental
impact.
4- Policy effectiveness: How much of the environmental impact could actually be alleviated
through feasible policy measures? It is unlikely that the entire harm described by the
indicator could be removed through a single policy.
* Other benefits of policies: There are often non-environmental benefits to certain policies.
For example, promoting walking may create a more livable neighborhood. This is not
captured in an environmental indicator of pollution.
INDICATORS CANNOT DEFINE ACCEPTABLE LEVELS OF IMPACT OR RATES OF PROGRESS
Indicators that show "large" impacts may be interpreted as meaning that action must be taken to
address a certain environmental problem. This would not be a completely accurate interpretation, at
least according to the economist's view of the world. The neoclassical microeconomic argument
would be that some level of pollution is acceptable. If the marginal cost of reducing the pollution is
equal to the marginal cost of the pollution, then further reductions would cost more than they would
be worth. It is possible that society is unwilling to improve environmental quality further in cases
where it would be exceedingly costly to do so. Political factors, public opinion, and legal
requirements all make the reality more complex than this simple economic argument would suggest,
of course. The point is simply that an indicator that seems to show a "large" impact is not an ironclad
argument that something must be done.
Rates of progress are equally difficult to interpret. Would a 2 percent annual improvement in a certain
environmental Indicator represent rapid or unacceptably slow progress? Such an indicator is open to
some interpretation, and in some cases even 10 percent annual progress may be deemed insufficient.
Trends in indicators must be interpreted carefully.
INDICATORS CANNOT SET TRUE PRIORITIES
In some cases, indicators cannot be put into comparable units, such as dollars of impact or numbers of
people injured. In those cases, it is clearly very difficult to use the indicators to set priorities. Even
when seemingly common units are used, such as tons released, the units may not be truly comparable,
since a ton of benzene causes more harm than a ton of NOX, and the harm may be greater if it is
released to a water supply near a city than if it enters the air in a rural area.
Furthermore, even when indicators are in comparable units (such as numbers of people affected with
respiratory problems or dollars of damage) it may still be inappropriate to set regulatory or budgetary
priorities based solely on such indicators. This is because, again, the costs of policies are not being
considered. Just because runoff is a bigger problem than tire disposal, for example, it may be much
less expensive to solve the tire problem. Setting priorities based on cost-effectiveness rather than just
environmental costs will accomplish more environmental benefit for a given, fixed budget.
That being said, we know that society often sets some rough priorities based on the size of various
problems, without considering the costs of fixing those problems. It may be reasonable to use
10
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What Indicators Can and Cannot Provid
indicators as a first tier of priority-setting, in the allocation of budgetary resources, for example,
where cost-effectiveness analysis would be impractical.
HOW INDICATORS CAN BE USEFUL
Given all of the caveats described above, one might be left with the impression that indicators are not
useful. That is far from true. As long as they are used appropriately, indicators are a very powerful
policy-making tool. Some of the uses of indicators are listed and then discussed below.
WHAT INDICATORS CAN BE USED FOR
•» Provide broad perspective
4 Encourage a comprehensive look at all environmental impacts
* Track progress of policies as a whole '
•» Highlight remaining problems
* Help set priorities, particularly for research and among issues needing new or improved
policies
-* Educate the public, media-focused offices, and others
* Feed into economic/policy analysis
PROVIDE BROAD PERSPECTIVE
Indicators can .provide a sense of the magnitude of transportation's environmental impacts relative to
other issues. Transportation could be compared with other sources of environmental damage, for
example, or these problems could be viewed relative to other large policy issues such as health,
education, economic problems, and crime. Indicators are very useful in conveying the importance of
an issue at the broad level. In this capacity, they can assist in resource allocation at the national level.
ENCOURAGE A COMPREHENSIVE LOOK
In the process of developing indicators, this,study has had to identify the full range 'of environmental
impacts of transportation. Likewise, in the process of using indicators, policy makers and the public
become aware of the whole gamut of ways transportation affects our environment. The awareness and
education that results is one of the often overlooked benefits of using indicators.
TRACK PROGRESS OF POLICIES AS A WHOLE
Indicators allow us to track progress, to measure success: While the results of a particular policy
initiative may not be discernible, the overall impacts of all of our activities, planned and unplanned,
can be seen with the appropriate indicators. This provides feedback that allows society to make mid-
course corrections and learn from past experience:
HIGHLIGHT REMAINING PROBLEMS
In using indicators to take a comprehensive look at environmental impacts, we may stumble upon a
"sleeper" issue: a problem that has been overlooked or neglected. Indicators encourage a full review
11
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Indicators of the Environmental Impacts of Transportation
of environmental issues and can highlight areas that have been ignored or have not been successfully
addressed.
HELP SET RESEARCH PRIORITIES
Indicators can also be useful in setting research priorities. The potential benefits of research are larger
when it is focused on the most significant environmental problems.
Reviewing the full range of impacts can be helpful in setting priorities. As discussed above, indicators
ideally would not be used as the sole method of priority setting, but they still can be valuable in this
role.
EDUCATE THE PUBLIC, MEDIA-FOCUSED OFFICES, AND OTHERS
Indicators are useful for educating the public about the range of issues, progress of policies, and
remaining challenges. They can provide a relatively simple overview of an issue such as
transportation's environmental effects.
They are also useful in governmental offices traditionally organized by environmental media, such as
air or water. For example, for a water-focused office, indicators could summarize the water quality
implications of a particular sector, such as transportation.
FEED INTO ECONOMIC/POLICY ANALYSIS
Indicators are an excellent starting point for policy analysis because they compile key quantitative
data on environmental impacts.
Now that we have taken account of the ways in which indicators should and should not be used, we
can consider how the most appropriate indicators can be selected. The next section examines the
question of how to design indicators.
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Selecting Appropriate Indicators
SELECTING APPROPRIATE INDICATORS
In this section, we examine the limitations of commonly cited indicators and then consider what an
ideal indicator would look like. We do so by presenting a framework that demonstrates how indicators
may focus on different stages of the link between transportation and the environment. Finally, this
section highlights data gaps that make use of ideal indicators unavailable at present, pointing to areas
in which research would be most beneficial.
COMMONLY CITED "INDICATORS" HAVE LIMITATIONS
Many of the measures often presented as indicators of transportation's environmental impacts are
flawed. Some examples of these measures and their limitations are listed in the table below.
LIMITATIONS OF COMMONLY CITED "INDICATORS"
MEASURE
VMT
MPG
Emissions per vehicle-mile
Emissions per PMT or per ton-
mile
Modal split
Acres of wetlands lost
Only a partial determinant of impacts. Increased VMT will
not increase emissions if technology improves, for example.
Only a partial determinant of impacts.
This is not a constant for all locations and all years. An
average national impact for one year cannot be applied to
other years or locations. Also, incorrectly implies that
benefits per VMT are constant.
Same as above. Incorrectly implies that benefits per PMT or
ton-mile are equivalent for different modes.
Only a partial determinant of impacts.
Does not consider the severity of the loss; assumes any acre
lost has equal value. May not consider mitigation efforts,
Perhaps the most important limitation to these measures is that they do not directly address the actual
impact, perhaps with'the exception of the wetland measure. They only measure activities that play
some role in leading to the impact. The need for results-oriented measures is discussed in the section
on ideal indicators. ' : •
The limitations of such measures can be briefly summarized as follows, and are discussed in some
more detail elsewhere in the report:
LIMITATIONS OF VMT AND OTHER COMMON MEASURES
* Results are more important to track than activities.
* Impacts per VMT or other activity measure vary a great deal by location.
+ Impacts per VMT~or other activity measure vary over time.
«• Average impacts are not useful when one should be measuring marginal impacts (the-effects
of incremental increases in travel are marginal impacts; there may be thresholds or other
13
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Indicators of the Environmental Impacts of Transportation
circumstances so that the impact associated with additional VMT differs from the average
impact per VMT).
The benefits per passenger-mile traveled (PMT) or per ton-mile are not equal for all modes
and locations.
While very limited as indicators, these types of measures do play some very important roles:
USES OF VMT AND OTHER COMMON MEASURES
4- They are critical data in models that predict environmental impacts. Local and national
analyses depend on these component data to model possible future impacts.
* They convey the magnitude and pervasiveness of the transportation system.
* They allow simple, rapid, cross-modal comparisons.
* They help explain historical and ongoing impacts, allowing policy makers to focus efforts on
these causal factors. For example, it may be helpful to observe that the fraction of commuters
driving to work alone ranges from just, 46 percent in New York State to 73 percent in
Michigan.21 In several cities, one third to one half of workers use public transportation,
compared with under one tenth in most cities and one twentieth nationwide.22 Such
comparisons may spur certain locations to reexamine their policies or infrastructure.
Some of these activity measures are discussed in Appendix A, which deals with infrastructure and
travel measures, as they relate to environmental quality.
One other type of indicator commonly cited deserves particular mention here. That is the group of
indicators measuring mitigation or control efforts. These are often programmatic measures that track
the dollars spent on mitigating environmental impacts or measure results such as the number of miles
of noise barrier installed, for example. Some of these measures go even further, to assess the
effectiveness of those mitigation or control efforts, citing statistics such as "current controls have .
reduced emissions per mile by 90 percent" or "these mitigation efforts are effective in 85 percent of
the cases." This report does not focus on mitigation or control efforts; instead, it looks at the net
impacts that result after such efforts have been attempted. This is not to say that such measures would
be useless. Measures of mitigation and control can be useful for the following purposes:
USES OF MITIGATION AND CONTROL INDICATORS
* To determine how well mitigation and control efforts are working
* To identify those practices or technologies that are most effective
4- To identify where such methods are not being implemented, to determine the need for
technology transfer, education, or incentives.
21 See World Resources Institute 1992. That report ranks cities based on usage of transit, walking, and
carpooling; time spent commuting; and share of population with commutes longer than 45 minutes.
^APTA, 1995.
14
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Selecting Appropriate Indicators
While development of mitigation and control indicators would be useful for these purposes, they are
not well suited for the goal of this study, which is to track the environmental impacts of
transportation.
Part of the reason that so many inappropriate measures are used as indicators of environmental
impacts is that a consistent framework is not being used to understand the process and design
appropriate indicators. Such a framework is presented below.
FRAMEWORK: HOW TO DESIGN INDICATORS
The figure on the following page presents a framework for the design and selection of environmental
indicators. It demonstrates how transportation activities (e.g., construction of infrastructure)
ultimately lead to impacts. It highlights the fact that indicators can be focused on any one of several
stages. Thus,- indicators could measure the root causes such as land use changes, or the activities
themselves (e.g., VMT), or the "outputs" of those activities (e.g., emissions), or finally, the actual
results, such as changes in public health. The figure also shows that unrelated activities, such as
industrial operations, also contribute to total emissions, making it difficult to isolate the impacts of
transportation if indicators are measuring ambient levels of pollution or public health, for example.
The framework shown here is very similar to a framework that has been used by EPA's Office of
Policy, Planning, and Evaluation, and the general approach has been found to be useful in a variety of
efforts. Variations of this framework have been used by-the Chesapeake Bay Foundation, for example,
and cited by the U.S. General Accounting Office in its EPA Management Review of 1988, in a chapter
entitled "Environmental Measures and Links to Program Activities Are Needed to Assess Program
Effectiveness" (GAO 1988). Because it has been found useful in past efforts, we have adapted the
framework to use in designing transportation environmental indicators. "
15
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Selecting Appropriate Indicators
The stages shown in the framework are listed below, with some examples of what is included in each
stage or what might be measured at each stage. These are not fully developed indicators in most cases,
and are not the actual quantitative indicators reported in this study. They are simply examples
representative of the range of factors that could be measured. The relative merits of various types of
indicators are discussed in the section, "What is an Ideal Indicator?" The actual indicators quantified
in this study are presented in Section V.
EXAMPLES OF INDICATORS TARGETING VARIOUS STAGES IN THE FULL TRANSPORTATION
CYCLE
ROOT CAUSE INDICATORS
Root cause indicators provide information on underlying factors, such as land use, demographics,,and
economics, that influence transportation activities. However, they are far removed from the actual
environmental effects and so tend to be poor measures of environmental damage. While these
measures do not provide a great deal of information for estimating the environmental consequences of
transportation, they do help explain the reasons why certain impacts may be increasing or decreasing.
As a result, tracking these root causes may have useful policy implications. Examples include the
following:
LAND USE (including demographics and geographic issues)
Population growth rate
Density (commercial, residential, or mixed; per square mile or zonal mile)
Transit access
Pedestrian environment factor (level of pedestrian accessibility)
Bike friendliness (including climate, terrain, safety issues, etc.)
ECONOMICS
Costs of travel by various modes
Income - - ' ' ,
Attitudes about environmental protection, transit, etc.
Knowledge/level of information regarding transportation costs (internal and environmental) and travel
alternatives
ACTIVITY INDICATORS
Activity indicators provide information on transportation actions, such as infrastructure construction
and maintenance; travel; and vehicle manufacture, maintenance, and disposal. In addition,
transportation infrastructure and vehicle fleet characteristics are included as indicators because they
may change over time and have continuing impacts (e.g., habitat fragmentation continues due to
existing roadways). Activities often have direct environmental consequences, and tend to be the most
consistently tracked indicators over time. However, the level of environmental damage associated
with a specific activity or jset of infrastructure varies by location and over time. Examples include the
following:
17
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Indicators of the Environmental Impacts of Transportation
INFRASTRUCTURE CONSTRUCTION AND MAINTENANCE
Number of lane miles constructed annually
Percent of roads that are paved/unpaved
Number of transit stations
Quantity of deicing compounds applied
VEHICLE AND PARTS MANUFACTURE
Number of vehicles manufactured
Number of railcars purchased by transit agencies
Number of new aircraft delivered
Number of registered vehicles
TRAVEL
Vehicle-miles traveled (VMT) (or VMT per capita)
Passenger-miles traveled (PMT) (or PMT per capita)
Number of trips
Average vehicle occupancy (AVO)
Modal split (percentage using transit, walking, driving alone, etc.)
Speeds (peak and off-peak)
Acceleration, stops, etc.
Congestion levels (e.g., share of travel in level of service "F', number of delay hours)
Gallons of fuel used (or average MPG for a given city or year)
VEHICLE MAINTENANCE AND SUPPORT
Number of cleaning or refueling stations/terminals
Number of active petroleum underground storage tanks
DISPOSAL OF VEHICLES AND PARTS
Number of vehicles scrapped
Number of used tires landfilled
Percent of mass landfilled or recycled
OUTPUT INDICATORS
Output indicators provide information on land take, emissions, ambient concentrations, or exposure.
They provide quantitative information about the actual environmental change that results from
transportation activities.
Ambient concentrations can be directly measured. However, they are by definition a local measure
(i.e., ambient ah" quality for a metropolitan area, water quality for a body of water), and thus, national
measures related to ambient concentrations generally do not provide a significant amount of detailed
information (e.g., number of metro areas exceeding the NAAQS, number of states reporting poor
18
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Selecting Appropriate Indicators
water quality due to runoff). In addition, ambient concentrations alone do not explain what portion of
the problem is attributable to a specific source (i.e., measuring ambient air quality does not directly
provide information about the contribution of transportation).
On the other hand, emissions can be estimated for a specific type of activity and tracked over time.
However, emissions estimates are generally based on models, which .may be somewhat flawed and
require improvement over time. Examples of each .of these indicators include the following:
HABITAT CHANGES/LAND TAKEN
Acres of various types of land disrupted or divided by roads, by type of land, including changes in
habitat fragmentation caused by transportation (e.g., number and size of parcels of forest or other
ecosystem) .. - . •
Acres of various types of land destroyed, accounting for mitigation/restoration (e.g., classified by
summarized wetland functions and values)
Number of threatened/endangered species in affected areas
EMISSIONS23
Tons emitted by mode, location, and chemical .
Levels of noise pollution .
Number of vehicles in use violating emissions standards
AMBIENT LEVELS
Parts per million of pollutant in ambient atmosphere, by location and chemical, for various averaging
times °
Number or percentage of areas in nonattainment of Federal air quality standards
Stream miles not meeting designated uses .
EXPOSURE TO POLLUTANTS
Number of, people living in nonattainment areas
Estimated amount of exposure in ppm-hours or other units
Population near .hazardous waste sites
Population downstream of areas with water quality problems or drinking affected water
OUTCOME INDICATORS
Outcome indicators are measures of end results. They provide quantitative information pn health,
environmental, and welfare effects resulting from transportation and are theoretically the most
desirable type of indicator. Unfortunately, quantified data on outcomes are often unavailable or
uncertain. Estimating end results generally requires using models (such as emissions dispersion
models and dose-response functions) that may involve various assumptions and introduce uncertainty.
Quantifying end results in dollar terms for purposes of comparison adds an additional step with
Emissions is a term typically used for pollutants released to the atmosphere, while discharge is the term used
for pollutants released to bodies of water. To avoid repetition of both words, this report used the term emissions
to denote releases of any type of pollutant to air, water, or land. " .
19
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Indicators of the Environmental Impacts of Transportation
considerable uncertainty. As a result, many of the current outcome indicators are nonspecific (e.g.,
states reporting habitat loss).
EFFECTS OF HABITAT CHANGE
Changes in abundance of various species caused by transportation
Changes in species diversity caused by transportation
Other detailed measures of:
Fishery impacts (e.g., number offish kills, changes in catch, and economic impacts on
fishing, recreation)
Forestry impacts
Agricultural impacts
Avian species impacts
EFFECTS OF POLLUTANT EMISSIONS
Expected (estimated) number of cases of a given health effect (e.g., cancer cases) attributable to
transportation emissions
Percentage of all cases thought to be caused by transportation
Risk level (i.e. probability that an individual will be affected)
Dollar costs of health or welfare impacts (e.g., dollars of textile damage from corrosive air pollution)
Person-days in exceedance of ambient standard (this is a measure of ambient levels but is also an
indicator of their effects)
The indicators listed above are representative of a very wide range of possible measures. The next
section discusses how one might go about selecting the most appropriate types of measures from
among these choices, taking into account both the traits of an ideal measure and the reality of existing
data gaps.
WHAT IS AN IDEAL INDICATOR?
Using the framework presented above, we can begin to consider the types of indicators that are most
appropriate. Data limitations and practical constraints currently require the use of indicators that are
less than ideal. It is important to consider, though, what an ideal indicator would look like so that
improved measures can be developed hi the long term.
We believe that ideal indicators would have the following characteristics:
CHARACTERISTICS OF IDEAL INDICATORS
4 Results-oriented
* Limited to only the share of harm attributable to transportation
4 Detailed enough for the target audience
• Presented in comparable units (e.g., dollars)
4- Presented in meaningful units (e.g., compared with a standard or goal)
4 Reasonable level of certainty
20
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Selecting Appropriate Indicators
Essentially, an indicator should accurately describe the actual damage caused by transportation in
units allowing comparison between indicators and providing a clear sense of the importance of the
impact Each of these issues is briefly explained below.
RESULTS-ORIENTED
Results-oriented indicators would focus on the last stages of the pro'cess shown in the framework,
namely health, environmental quality, and welfare. The advantage of results-oriented measures is that
they measure the factors with which people are really concerned. Unfortunately, actual measurements
of these results are typically scarce. This necessitates modeling, making the indicators less certain.
RESULTS-ORIENTED INDICATORS
PROS Measure the problem itself; get incentives right
Data often available for overall extent of problem
CONS i Data often unavailable to attribute share of damage to a single sector
Data often uncertain, based on numerous modeling assumptions
Do not explain causes of problem or solutions
Another problem with pure results-oriented measures is that they provide no insight into possible
solutions, or what the specific root causes are. Even if one knew how many cases of cancer are caused
by automobiles, one would still need to understand more about why so many people are exposed to
these pollutants, why emissions are so high per mile, how much travel occurs and why, and so on. To
better understand root causes and possible solutions, policy makers often measure activities such as
miles traveled, average vehicle occupancy, or miles per gallon. The disadvantage to measuring root
causes or travel activities is that they are not equivalent to the problem one is trying to solve. Using
indicators of VMT, for example, does not set the perfect incentives. Tracking VMT suggests the goal
is to reduce VMT, but the real goal is to reduce health or other problems. Thus, VMT could remain
constant, but a shift to more polluting vehicles would still pose a threat.
Perhaps a larger challenge, though, in developing results-oriented measures, is limiting the indicator
to transportation's share of the impact, as explained below.
LIMITED TO ONLY THE SHARE OF HARM ATTRIBUTABLE TO TRANSPORTATION
Data are often available for at least overall health indicators, such as the number of Americans dying
from respiratory diseases in a given year. The'problem with such indicators is attributing some share
of these effects to a single set of activities, such as transportation. Ideally one would like to know the
number of deaths caused by air or water pollution from transportation. Even if one can measure
ambient air quality or the number of cases of respiratory disease, it is difficult to isolate the share of
these problems that stems from transportation (see the following figure). Industrial and other sources
contribute emissions and it is often impossible to measure transportation's impacts separately. The
exceptions would be in cases where transportation emits a unique pollutant (e.g., perhaps road salt or
car batteries) or entails an activity that could be observed and counted directly, such as the acreage of
wetlands filled by highway projects.
21
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Indicators of the Environmental Impacts of Transportation
If transportation's share of impacts cannot be directly measured, it must be modeled. Modeling
results-oriented measures introduces some uncertainty and sometimes requires data that are
unavailable or impractical to obtain.' For example, it is difficult to accurately estimate the amount of
pollution entering lakes that results from automobiles.24 ' .
Because of these data limitations, results-oriented measures focused on only transportation's share of
the problem are currently very difficult to develop. This report therefore presents many indicators
focused on emissions, an earlier stage in the process shown in the framework above.
The variety of sources of air pollution mean that it is difficult to determine
transportation's share of impacts by measuring ambient pollution levels alone.
Ambient Levels of
Pollution
Mobile Sources
Stationary and Other Sources
DETAILED ENOUGH FOR THE TARGET AUDIENCE
The design of indicators must take into account the audience. Indicators that are ideal for regional
officials implementing highway programs may not be useful to Congress in considering new
legislation. The appropriate level of detail depends on the consumers of the information. We have
chosen to attempt a balance between excessive detail (e.g., numerous measures of flora and fauna
impacts) and insufficient detail (e.g., total dollar cost of all environmental impacts, VMT growth rate,
or total tons emitted for all air pollutants added together).
PRESENTED IN COMPARABLE UNITS (E.G., DOLLARS)
Ideal indicators would be expressed in comparable units, to allow comparisons among impacts,
modes, and media. Dollars are one common unit that has been used to assess some environmental
impacts, but there is considerable uncertainty and sometimes controversy over using such units.
Estimates in common terms currently are not available for many of the impacts. This report does not
present indicators in common units.
34 Estimates of air deposition do exist, as discussed in the section presenting indicators.
22
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Selecting Appropriate Indicators
PRESENTED IN MEANINGFUL UNITS (E.G., COMPARED WITH A STANDARD OR GOAL)
Meaningful units provide a sense of how important an impact is. Indicators expressed in terms of tons
emitted or percentage improvement per year, for example, are limited because they do not convey a
sense of how many tons is "bad" or what rate of progress is "good." Comparison with a standard
places the impact in context. The standard,could be a legal one or a goal set through the political
process. Compliance rates or comparisons with health standards provide such a perspective.
Unfortunately, there are not yet sufficient standards or related data to allow indicators that provide
this full level of context for all environmental impacts of transportation. Developing such standards
and data would make indicators even more useful.
REASONABLE LEVEL OF CERTAINTY
• An ideal indicator would have a reasonable degree of certainty. Nearly all indicators at the national
level—from root causes to outcomes—have some unavoidable degree of uncertainty. Total national
VMT is not directly measured but instead is estimated based on traffic counts from a sample of roads.
Undertaking the additional step of estimating emissions requires modeling assumptions, which further
reduce certainty. Estimating end results (e.g., health effects, damage) again introduces a series of
assumptions which deters from the certainty of the final indicator. While outcome indicators measure
what is most important to people, it is important to balance the goal of having results-oriented
indicators with the goal of reasonable certainty.
AVAILABLE INDICATORS
As the preceding discussion makes evident, ideal indicators are a long-term goal but are rarely
available. This report presents results-oriented measures, or outcome measures, where they are
available. Most of the indicators presented here, however, are output measures, or measures of
emissions and habitat change rather than actual results. They are presented as interim solutions, with
the understanding that ideal'indicators should be developed.
(
DATA GAPS
Ideal indicators are not yet available for most of the environmental impacts of transportation, largely
as a result of data gaps. This section gives an overview of those gaps.
LOCAL VERSUS NATIONAL DATA
Particularly in national-level data, the necessary statistics are not available to describe many of the
impacts associated with various modes of transportation. This is because most impacts are first
measured or estimated locally, in environmental impact statements (EISs) or laboratory, studies, for
example, and then converted to national estimates. National estimates may be compiled in a few
different ways: 1) by directly observing, or counting, all of a given transportation impact (e.g.,
counting every acre of wetland affected on a project-by-project basis) and then adding up the
numbers; 2) by observing typical impacts, ideally based on a representative sample, and multiplying
by a scaling variable like VMT; 3) by forming a multivariate model, scaling up to a national estimate
using several variables rather than VMT alone; or 4) by observing the total impact (e.g., ambient air
quality or human morbidity) and estimating the fraction attributable to transportation. Each of these
approaches has been used for some estimates of transportation's impacts, and we present the most
reliable of the various figures available.
-------
Indicators of the Environmental Impacts of Transportation
SUMMARY TABLES OF DATA GAPS ORGANIZED BY ENVIRONMENTAL MEDIA
The specific data gaps in national environmental indicators for transportation will become apparent in
the presentation of actual indicators, but the charts below provide an overview of the broad areas
where more information is needed. The summary table provides a synopsis of the general types of
environmental impacts that should be measured, and the next table provides a sketch of where data
gaps exist. It should be noted that where the table states "good indicators" are available, the term
"good" is used in a relative sense. Very few excellent indicators exist, since they would require
further research and development. As a result, the table simply identifies areas in which data are
generally better.
It is important to note that these tables, unlike the rest of the report, classify impacts by environmental
medium, such as air or water. This approach (organizing by media) is taken only in these tables, as a
convenient means to provide a brief summary and because much of the necessary scientific research is
medium-specific.
Following these tables on data gaps, the next section of this report introduces the primary
classification scheme actually used to categorize impacts and indicators of those impacts
24
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65
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Categorizing'the Environmental Impacts of Transportation
IV. CATEGORIZING THE ENVIRONMENTAL
TRANSPORTATION
One of the potential benefits of environmental indicators is that they encourage a comprehensive view
of impacts. A key part of this study was the development of a scheme to categorize the full range of
environmental impacts of transportation. This section describes this scheme and summarizes the
impacts we have considered. The section after this one lists the actual quantitative indicators of each
impact. , ,
Many reports citing the impacts of transportation do not use a set of categories, often focusing on air
pollution and noise to the exclusion of other impacts. Some include a few additional impacts, but not
in any organized, comprehensive manner. A long list of impacts without a scheme for categorizing
them logically can be confusing. •
Some governmental agencies are traditionally organized by environmental medium. That is to say,
there is an air office, a water office, a hazardous waste office, and so on. While this approach has
some advantages, it is not well suited for an examination of a single industrial sector or group of
related activities, such as transportation.
We have chosen to classify the impacts of transportation according to five key types of activities
rather than by media.-Focusing on activities as the primary organizing principle makes the categories
easy to understand and policy relevant. The key activities that are involved in transportation are listed
below. .
FIVE BASIC ACTIVITIES CAUSING ENVIRONMENTAL IMPACTS
The five basic groups of transportation activities that cause environmental impacts are listed below.'
These are listed in a somewhat chronological order, following the life cycle, of transportation.
BASIC TRANSPORTATION ACTIVITIES AFFECTING THE ENVIRONMENT
1. Infrastructure construction, maintenance, and abandonment
2. Vehicle and parts manufacture
3. Vehicle travel .
4. Vehicle maintenance and support
5. Disposal of used vehicles and parts •
As noted earlier, these groups cover a wider range than typically considered. This study and most data
sources emphasize the third group, vehicle travel, but we have included at least some information on
each of these steps in the full life cycle of transportation.
27
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Indicators of the Environmental Impacts of Transportation
DETAILED LIST OF ACTIVITIES CAUSING ENVIRONMENTAL IMPACTS
Each of the five basic types of transportation activities can be subdivided into several types of
environmental impacts. For example, vehicle travel causes exhaust emissions, noise, and hazardous
materials spills. Infrastructure development results in disrupted habitat as well as emissions during
construction or maintenance. The environmental impacts are listed below, as subcategories of the five
basic transportation activities.
It should be noted that the lists below identify the impacts but are not the actual indicators that would
be used to measure those impacts. The indicators of these impacts are shown in the section following
this one.
2S
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Categorizing the Environmental Impacts of Transportation
HIGHWAY TRANSPORTATION ACTIVITIES AND THEIR IMPACTS
1. Road Construction and Maintenance .
4 Habitat disruption and land take for road and right-of-way
4 Emissions during construction and maintenance
4 Releases of deicing compounds
4 Highway runoff "
2. Motor Vehicle and Parts, Manufacture . ,
4 Toxic releases and other emissions
3. Road Vehicle Travel
4 Tailpipe and evaporative emissions '
* Fugitive dust emissions from roads
* Emissions of refrigerant agents from vehicle air conditioners '
4 Noise . -
4 Hazardous materials incidents during transport
* Roadkill
4. Motor Vehicle Maintenance and Support
4 Releases during terminal'operations: tank truck cleaning, maintenance, repair, and refueling
* Releases during passenger vehicle cleaning, maintenance, repair, and refueling
4 Leaking underground storage tanks containing fuel
5. Disposal of Motor Vehicles and Parts25
4 Scrappage of vehicles
4 Improper disposal of motor oil
4 Tire disposal
4 Lead-acid batteries disposal
The disposal of used motor oil and tires could have been classified as part of vehicle maintenance. It occurs
during maintenance, not only at final disposal of the vehicle and its parts. We have chosen to include it in this
category, however, for convenience and because waste disposal policy issues differ from those involved with
other impacts of vehicle maintenance.
29
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Indicators of the Environmental Impacts of Transportation
RAIL TRANSPORTATION ACTIVITIES AND THEIR IMPACTS
/
/. Railway Construction, Maintenance, and Abandonment
4 Habitat disruption and land take
4 Emissions during construction and maintenance
2. Rail Car and Parts Manufacture
4 Toxic releases
3. Rail Travel26
4 Exhaust emissions
4 Noise
4 Hazardous materials incidents during transport
4. Rail Car Maintenance and Support
4 Releases during terminal operations: car cleaning, maintenance, repair, and refueling
4 Emissions from utilities powering rail27
\
5. Disposal of Rail Cars and Parts2*
4 Rail car and parts disposal
26 Emissions of refrigerant agents could also be included here, but no data were identified to address this potential
impact.
17 Emissions from utilities powering rail could also be categorized as a part of rail travel but are listed here
because it is a stationary source legally and emissions do not occur at the point of travel.
28 Disposal of oil and other used parts could be included here, but no relevant data were identified.
30
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Categorizing the Environmental Impacts of Transportation
AVIATION TRANSPORTATION ACTIVITIES AND THEIR IMPACTS
1. Airport Construction, Maintenance, or Expansion
4 Habitat disruption and land take
4 Emissions during construction and maintenance
4 Releases of deicing compounds •
4 Airport runoff ,
2. Aircraft and Parts Manufacture
4 Toxic releases
3. Aviation Travel
4 High altitude emissions - • •
4 Low altitude/ground level emissions
4 Noise impacts
4 Hazardous materials incidents during transport
4. Airport Operation
4 Emissions from ground support equipment involved in aircraft loading, cleaning,
maintenance, repair, and refueling
5. Disposal of Aircraft and Parts29
4 Airplane and parts disposal .
29 The disposal of used motor oil and tires could have been classified as part of vehicle maintenance. It occurs
during maintenance, not only at final disposal of the vehicle and its parts. We have chosen to include it in this
category, however, for convenience and because waste disposal policy issues differ from those involved with s
other impacts of vehicle maintenance.
31
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Indicators of the Environmental Impacts of Transportation
MARITIME TRANSPORTATION ACTIVITIES AND THEIR IMPACTS
1. Construction and Maintenance of Navigation Improvements
4 Direct deterioration of habitats and water quality from dredging or other navigation
improvements
* Habitat disruption and contamination from disposal of dredged material
* Habitat disruption and land take for ports and marinas
2. Manufacture of Maritime Vessels and Parts
4 Toxic releases
3. Maritime Vessel Travel
4 Air pollutant emissions
4 Habitat disruption caused by wakes id anchors
* Introduction of non-native species
• Hazardous materials incidents during transport
* Wildlife collisions
* Overboard dumping of solid waste
4 Sewage dumping
4. Maritime Vessel Maintenance and Support
4 Releases of pollutants during terminal operations
5. Disposal of Maritime Vessels and Parts
4 Scrappage of old vessels and dilapidated parts
32
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The Indicators
V. THE INDICATORS
This section of the report presents the actual indicators and uses them to quantify the various
environmental impacts of transportation. Separate subsections describe the following modes:
4 Highway •
* Rail '
* Aviation
4 Maritime
As explained in the previous section, the primary categories used here are types of activities. The
discussion of each environmental impact includes the following information:
* Presentation of indicators
* Description of impact
* Causal factors
Three types of indicators are presented throughout this report:
* Outcome/Results Indicators
Outcome indicators are measures of end results. They provide quantitative information on
health, environmental, and welfare effects resulting from transportation, and are theoretically
the most desirable type of indicator. Examples of good outcome indicators include the number
• of cases of headaches or other human health symptoms incurred, the number of animals killed,
and the extent of wetlands or other specific habitats destroyed. Unfortunately, in many instances
quantitative data are available for only crude outcome indicators, such as the number of states
reporting wetland degradation or groundwater contamination. In other cases, large uncertainties
exist regarding transportation's share of a given outcome. While this information is useful, it is
not a sufficient indicator for most environmental or policy analysis.
* Output Indicators
Output indicators provide information on emissions, ambient concentrations, land take, or
exposure. These indicators tend to be more reliable than many of the available outcome
indicators. Examples of good output indicators include the area of new land taken, quantity of
air pollutants emitted, and quantity of oil spilled. While these data are recognized as fairly
accurate, much of the information is based on models or reports of incidents which may not be
comprehensive. In most cases, estimates of actual exposure, such as the number of people
exposed to air pollution from motor vehicle manufacture or the amount of hazardous materials
spilled that actually enters the environment, are not reported.
* Activity Indicators
Activity indicators provide information on infrastructure, travel, and other .transportation-related
activities, such as vehicle and parts manufacture, maintenance, and disposal. Examples of
infrastructure data include the number of railroad terminals, road mileage, and number of
' underground petroleum storage tanks. Examples of travel and other activity measures include
the number of vehicles scrapped, quantity of deicing agents used, energy consumed, and
33
-------
Indicators of the Environmental Impacts of Transportation
vehicle-miles traveled. Although these measures provide only an indirect indication of
environmental impact, in some cases they are the best indicators available.
34
-------
The Indicators: Highway
HlSHWAY €NVfRONIS!iiNTAL INDICATORS
This section presents the quantitative indicators available for tracking the nationwide environmental
impacts of highway (on-road motor vehicle) transportation. For each of the five basic categories of
activities affecting the environment, the various impacts are listed.
HOW EACH IMPACT IS PRESENTED IN THIS SECTION
Each environmental impact is covered in one or more pages of text and graphics, with the following
key subsections:
4 Presentation of indicators
The key indicators that have been quantified are presented. Outcome
- indicators are listed first since they provide information on end results and
are theoretically the most desirable type of indicator. Unfortunately, actual
quantified data are often unavailable or of poor quality. In many instances,
the only available data on outcomes are the numbers of states reporting a
problem. This information is often incomplete (not all states may examine the
problem), vague (states may define the problem differently), or only
somewhat relevant (the contribution of transportation to the problem may be
unknown). As a result, output indicators—such as emissions, data—are
presented. These statistics may be an easier and more valid measure for
policy makers ,to examine and track over time. Activity indicators (defined
broadly to include infrastructure, travel, and other activities) are listed when
they are the best available indicators or when outcome and output indicators
are not adequate. In some cases, local examples are also provided.
To avoid repetition within the report, basic infrastructure ,and travel
indicators are listed in Appendix A for each mode of transportation.
Appendix B contains additional relevant statistics on monetized values of
health and other impacts; these outcome indicators are listed separately since
there is generally more uncertainty regarding these figures.
* Description of impact
The nature of the impact is briefly' defined and explained here. More
complete descriptions of these impacts are available in reference works listed
in the bibliography.
Causal factors: Variables that change over time and between locations
35
-------
Indicators of the Environmental Impacts of Transportation
Policy makers find it very useful to understand the driving forces behind
environmental impacts. Understanding the key causal factors, such as VMT or
emissions rates in grams per mile, is critical to explaining observed trends in
indicators. They also help in estimating how local impacts may differ from national
averages. These causal variables, then, explain how the impacts differ over time and
geographic location. Most importantly, they suggest potential policy levers. Policies
can be designed to focus on any of the key variables (e.g., grams emitted per mile)
that determine the magnitude of an environmental impact.
The following table provides an overview of the available indicators for each impact. It is important to
note two points about what is included in this table: First, indicators are listed only where they have
been quantified at the national level; if an impact has not been quantified, no "potential" indicator is
listed here. For each specific activity and its impact, the table provides a summary of the availability
of quantitative data for indicators of outcomes, output, and activity. Second, the table shows only the
best indicator for each impact rather than listing various alternative types of indicators for a given
impact. The exceptions are when multiple indicators are needed to address all aspects of an issue or
where some indicators are otherwise insufficient. Although outcome indicators are theoretically the
most desirable type of indicator, actual quantified outcome data are often unavailable or of poor
quality. As a result, output indicators—such as emissions levels—tend to be the most reliable and
valid measures available in most cases. Activity indicators are presented in this table when they are
the best available indicators or when outcome and output indicators are not adequate.
36
-------
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-------
-------
The Indicators: Highway
1. ROAD CONSTRUCTION AND MAINTENANCE
Because of the space and infrastructure required by some roads, particularly multi-lane freeways, the
construction and maintenance of roads can have a significant impact on natural resources in and
around the right of way. Common problems associated with infrastructure include habitat disruption,
hydrologic alterations, and polluted runoff. In addition, road.construction activities may have
temporary, but significant, environmental impacts caused by land take for depots and road hauls,
drilling and excavation activities, disposal of excess material, discovery of hazardous material in the
right-of-way, and use of construction machinery. Such impacts are discussed below, and further
' material on infrastructure is available in Appendix A.
Air Pollutant Emissions during
Construction/maintenance
Habitat Disruption
Application of
De-icing
Compounds
Highway Runoff
affecting Water
Quality
HABITAT DISRUPTION AND LAND TAKE FOR ROAD AND RIGHT-OF-WAY
PRESENTATION OF INDICATORS
QUANTIFIED OUTCOME/RESULTS INDICATORS
4 Of the 27 states that listed wetlands losses in their 1992 305(b) reports, 14 states reported
they had losses due to highway construction (U.S. EPA, 1994b). Other sources of loss
included agriculture (21 states), commercial development (19 states), and residential
development (16 states).
41
-------
Indicators of the Environmental Impacts of Transportation
States Reporting Loss of Wetlands
Due to Highways
States Reporting
Wetlands Loss
Highway as a
Cause
14
Source: U.S. EPA, 1994b.
* Eight states reported that road construction was a source of degraded wetlands integrity, out
of 14 states that describe wetland integrity impacts (U.S. EPA, 1994b). Most states do not
quantify wetlands areas affected by pollutants and their sources.
QuwmsD OUTPUT INOKATORS
* Nationwide, roads take up approximately 10.93 million acres of land, or 17,080 square miles
of land, not including road shoulders and medians (Apogee estimate).30 Of this total:
4- Rural roads and highways take up approximately 8.47 million acres of land or 13,240
square miles of land. This area is larger than that of the state of Maryland.
4 Urban roads and highways take up approximately 2.46 million acres of land or 3,840
square miles of land. This area is larger than that of the state of Delaware.
* Nationwide, roads occupy less than 0.5 percent of U.S. land area (Apogee estimate)/
4 Interstate highways occupy approximately 457 square miles of land, or less than 0.01
percent of U.S. land area.32
* In 1993, roads (including local and unpaved roads),occupied an average of about 1.1 mile of
road per square mile of land (however, the amount of roads per square mile in urban areas is
significantly higher) (Apogee estimate).33
4 In 1993, interstate highways occupied an average of about 23 yards (0.013 mile) of road per
square mile of land in the U.S. (Apogee estimate).34
, 31
QtMOTJBeo ACTIVITY tecarons
4 Between 1983 and 1993, there was a net increase of 25,083 road miles in the U.S., a 0.6
percent increase in road-mileage during the 10-year period (FHWA, 1995e).
M Values calculated based on number of lane miles in 1993 times average width per type of road: Interstate
highways-12 ft., Rural other arterials-11.9 ft., urban other arterials-11.8 ft., rural collectors-11 ft, urban
collcctors-11.3 ft, local roads-11 ft. (U.S. DOT, FHWA, 1994c).
3117,080 square miles of land, as calculated above, divided by 3,536,278 square miles U.S. land area.
32 Values calculated based on number of lane-miles in 1993 times average width per interstate highways (12 ft).
(U.S. DOT, FHWA, 1994c).
33 3,904,721 miles of road (U.S. DOT, FHWA, 1994c) per 3,536,278 square miles U.S. land area.
34 45,530 miles of interstate highway (U.S. DOT, FHWA, 1994c) per 3,536,278 square miles U.S. land area.
42
-------
The Indicators: Highway
Between 1988 and 1993, there was a net increase of 41,605 lane miles in the U.S. on non-
local roads (interstate, other arterials, and collectors), a 1.5 percent increase in lane-mileage
during the 5-year period (Apogee estimate).35
In 1993, roadway projects under construction consisted of 504 miles of new routes and 3,188
miles of capacity additions (EHWA, 1994c).
From 1989 to 1993, an average of 13,724 miles of roadway were under construction in each
of the 5 years. System preservation represents the largest portion of roadway projects.
Construction of new routes fell by 24 percent nationwide between 1989 and 1993. Growth
rates in some regions, however, are much higher (FHWA, 1994c).
From 1989 to 1993, an average of 529 miles of new routes and 2,933 miles of capacity
additions were under construction annually (FHWA, 1994c).36
OTHER QUANTIFIED DATA AND LOCAL EXAMPLES
4 Some states track acreage of wetlands lost and gained as a result of highway construction,
with the objective of realizing no net loss (e.g., Florida, Kentucky, New Jersey) (SRI
International, 1993).
* Honda and Oregon track the number and type of endangered or threatened species impacted
by highway construction and operation (SRI International, 1993).
4- . Four states (-13 percent of those responding) have conducted studies on biodiversity effects
of highways: Louisiana, West Virginia, Virginia, and Pennsylvania (Herbstritt and Marble
. 1996). '
4 Wisconsin reports that from 1982 to 1989, a total of 11,800 acres of wetlands were lost due
to permitted discharges of dredged or fill material from state DOT highway projects, or
almost 70 acres per year (U.S. EPA, 1994b).
DESCRIPTION OF IMPACT
Viewed in broad, relative terms, the habitat impacts of road construction have taken place over
decades, and new impacts are now growing at an extremely low rate. While a substantial amount of
construction occurred in the past, road mileage is barely increasing nationwide. The habitat impacts of
existing infrastructure, however, are ongoing in the sense that habitats remain fragmented as long as
they are divided by roads. Furthermore, road construction in certain high-growth locations and near
sensitive habitats can still have significant impacts.
The total land area occupied by all existing roads is relatively small: all roads, paved and unpaved,
occupy less than 0.5 percent of U.S. land area. This may be contrasted with forests, which cover
roughly 31 percent of the country, and land used for crops and pasture, which also covers large
percentages of the country (WRI, 1994). Even wetlands still cover about 5 percent of the lower 48
states '(Dahl and Johnson, 1991), and the 39 largest metropolitan areas cover about 5 percent of U.S.
land. This makes clear that roads themselves, and even cities, do not occupy a very large amount of
potential habitat in simple percentage terms. Their impact on habitat results more from indirect effects.
on surrounding habitat and bodies of water than from actual displacement of acreage, as discussed
below. In addition, the physical land area estimates reported above underestimate the extent of total
35 Lane miles on non-local roads increased from 2,733,309 miles in 1988 to 2,774,914 miles in 1993 (U.S DOT,
FHWA, 1994c and 1988 edition).
Note that construction on a project may span more than one year.
43
-------
Indicators of the Environmental Impacts of Transportation
habitat affected by highways since they exclude road shoulders and medians, and transport-related
areas, such as parking lots, garages, and gas stations.
Introducing roads and associated infrastructure into the environment has led to the destruction or
disruption of habitats in the right-of-way. Roads damage existing vegetation, interfere with wildlife
crossings, displace forests and communities of animals and birds, and alter the hydrology of various
areas, including drainage, permeability, and stream flow patterns.
Roads split natural habitats such as forests, causing "fragmentation," decreasing habitat size and
reducing interaction with other communities. This fragmentation is known to produce declines in both
the number of species (diversity) and their populations (abundance) (Tolley, 1995). A study of the
influence of narrow forest-dividing corridors (small roads and powerlines) on forest-nesting birds in
southern New Jersey revealed that, although not generally viewed as sources of forest fragmentation,
such corridors measurably affect the diversity and abundance of birds in ways that are associated
typically with the effects of forest fragmentation (Rich et al., 1994).
Highway construction has also been cited as an activity that contributes to wetlands destruction and
loss of mangroves, seagrass, marshes, and swamps—habitats that support a diverse range of species
and provide other desirable functions such as flood control (Hall and Naik, 1989 as cited in Barrett et
al., 1993). In the past 200 years, the U.S. has lost over half of the original wetlands acreage in the 48
coterminous states. In recent years, 300,000 acres have been lost annually, or a 3 percent loss per
decade. Over half of these recent losses have been caused by conversion to agricultural use, and only
4 percent were identified as conversion to urban land (Dahl and Johnson, 1991). The amount of
wetlands acreage lost annually is over 20 times higher than the amount of new land used by roads.
Furthermore, compensatory mitigation efforts are currently undertaken to mitigate for unavoidable
habitat loss, under a "no net loss" policy. However, a FHWA study evaluating the success of 23
highway-related wetland mitigation projects indicated that very few of the sites resulted in full
replacement of all wetland functions lost to construction (U.S. DOT, 1992). Also, as stated in the
indicators above, some states still report wetlands loss due to highways.
Wetlands are an important resource. Wetlands are essential to over half of the endangered fish species
and half of the endangered amphibian species in the U.S. (Water Environment Federation, 1992). As
some scholars suggest, "Destruction and modification of habitat are probably the most serious causes
of falling amphibian populations [worldwide]. Like other animals, amphibians are threatened when
forests are destroyed and wetlands are filled in or paved. Indeed, such activities probably account for
the decrease in a majority of species threatened today—The loss—deserves attention—because frogs
and their kin...may serve as indicators of the overall condition of the environment." (Blaustein and
Wake, 1995) Wetlands also provide economic benefits: a $28 million sport fishing industry and two
thirds of commercially harvested fish and shellfish species (Water Environment Federation, 1992).
Runoff from construction sites can cause erosion, sedimentation, and other changes disrupting aquatic
habitats such as fish-spawning areas and river-bottom habitats. Suspended solids reduce the aquatic
food supply by blocking light and reducing photosynthesis. They also abrade aquatic organisms,
affect fishing and recreation uses, and reduce capacities in downstream reservoirs (Barrett, 1995).
Construction of roads can also reduce water storage and spring flow, threatening species during
droughts. When natural ground cover is present over an entire site, normally less than 10 percent of
the stormwater runs off into nearby rivers and lakes. As paved surfaces increase, both the volume and
the rate of runoff increase. When paved surfaces cover 10-30 percent of the site area, approximately
44
-------
The Indicators: Highway
, 20 percent of the stormwater can be expected to run off (U.S. EPA, 1982). Pollutants, washed from
land surfaces and carried by runoff into lakes and streams, may add to existing water quality
problems, as discussed in the section on runoff impacts/7 Furthermore, paved surfaces prevent natural
infiltration of stormwater into the ground.
Other road transportation infrastructure, such as buildings and bridges, also may have habitat impacts.
For example, bridges and stream crossings are likely to have significant impacts on hydrology and
aquatic habitat. However, the physical extent of roads is far greater than that of these other structures.
CAUSAL FACTORS . .. ,
* Size of habitat fragments between roads and width of corridors
* Lane-miles of new road .(widening and new routes)
> Bridges and other highway infrastructure constructed
* Type of construction activity (maintenance versus capacity expansion)
4 Type of road surface (paved/unpaved) ,
4- Successful implementation of various efforts to avoid or mitigate impacts (e.g., wildlife
crossings)
* Ecological conditions/type of land (i.e., wetlands, forest, etc.)
4 Species/habitat in and near the right of way ;
EMISSIONS DURING CONSTRUCTION AND MAINTENANCE
PRESENTATION OF INDICATORS
QUANTIFIED OUTCOME/RESULTS INDICATORS
* New building and major land development projects, including highway construction, produce
sediment and toxic materials which are estimated to degrade up to 5 percent of the nation's
surface waters (Griffen, 1991). The contribution of highway construction is unknown, but is
most likely a small proportion.
QUANTIFIED OUTPUT INDICATORS - ' - '
4 National statistics for emissions from transportation-related construction activities are
generally not available. At the local level, emissions from construction are discussed on a .
case-by-case basis in the project's EIS.
* Construction activity impacts, though localized, may generate sediment levels 10-20 times
greater than agricultural land uses, affecting aquatic habitat (Griffen, 1991).
* • Contamination is often reported as encountered in highway maintenance.
For a more detailed discussion on pollutants contained in urban runoff, see the section, "Highway and Road
Runoff."
45
-------
Indicators of the Environmental Impacts of Transportation
CONTAMINATION ENCOUNTERED IN HIGHWAY OPERATIONS AND MAINTENANCE
(NCHRP, 1993; based on telephone survey of 16 states38)
* Lead Paint: All states reported that lead paint residues from bridges were a problem.
* Solvents and Pesticides: Four states had significant problems with solvents and pesticides at maintenance
yards and with solvents as laboratory wastes, from asphalts in particular.
* Salt: Two states had problems with salt runoff from maintenance stockpiles contaminating groundwater.
» General Maintenance: Six states volunteered that they had problems at their maintenance facilities.
Quwmeo ACTIVITY INDICATORS
4 Between 4.1 to 12 million tons crude oil equivalent were required to lay the 25,083 miles of
new road constructed in the U.S. between 1983 and 1993 (VHB, 1992; FHWA, 1995e).
* Approximately 90 percent of the steel bridges in the U.S. are protected from corrosion with
lead-based paints. Use of such paints can lead to significant containment and disposal
problems (Pinney, 1995).
* In 1986, herbicides (e.g., Roundup and 2,4-D) were used on 1.5 million roadside acres in the
38 states reporting. Acreage treated rose 56 percent from 1982-1986 while reported acreage
of responsibility fell by 6 percent (TRB, 1988).
Roadside Acres Treated with Herbicides
f 1,400 .
0
* 1,000 .
I 600 .
t200 .
n
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•*: ' !
Acres Treated with Herbicide
- Roadside Treated 0.3%
Cropland
1980 1983 1986
Source: TRB, 1988.
Source: TRB, 1988
OTHER luacATOffS AND LOCAL EXAMPLES
* Highway construction in West Virginia uncovered pits and caverns overlaying an aquifer
supplying a fish hatchery. Large quantities of clay and silt washed into the caverns, resulting
in very turbid springflow during storms. In one dramatic (not typical) event, more than
150,000 trout died due to silt build-up on their gills (Garton, 1977 as cited in Barrett et al.,
1993).
* Repainting of the Verrazano Bridge is expected to generate 2,800 tons of hazardous waste,
and will involve a containment system with negative air pressure to capture paint spray
(Greenman et al., 1995).
38 States surveyed: Alaska, Arizona, Florida, Illinois, Louisiana, Minnesota, Missouri, Montana, New
Hampshire, New York, Oregon, Pennsylvania, Tennessee, Texas, Virginia, and Washington.
46
-------
The Indicators: Highway
DESCRIPTION OF IMPACT -
The quantity of emissions from construction operations is related to the area of land being worked and
the type and level of construction activity. The environmental impact of any particular project •
depends on the location and condition of the surrounding area, the size and type of road constructed,
and the project's duration. Environmental impacts will also vary according to construction techniques
and pollution management techniques employed, as well as mitigation measures undertaken.
Emissions during road construction are associated with land clearing, blasting/ground excavation,
and cut and fill operations. The construction of the facility itself may cause changes in turbidity,
suspended solids concentration, and color of receiving waters. Temporary storage facilities for
equipment and supplies used during the construction phase may also damage vegetation and displace
communities of animals. Note that it is difficult to isolate the effects of highway construction from the
effects of land-use changes, socioeconomic changes, and natural ecological changes in receiving
water bodies. '
Dust emissions, much of which result from equipment traffic over temporary roads at the construction
site, may have substantial temporary impacts on local air and water quality. Construction can also
affect the environment through exhau'st emissions from machinery and haulage vehicles, spillage
during refueling, and noise. In general, between^VO and 800 tons of crude oil equivalent are required
to lay 1 mile of a paved four-lane highway (OECD, 1988 as cited in VHB, 1992). This figure does not
include energy used in asphalt production or preparing the ground for paving. Based on this estimate,
between 4.1 to 12 million tons crude oil equivalent would be required to lay trie 25,083 miles of new
road constructed in the U.S. between 1983 and 1993 if they all consisted of paved highway (Apogee
estimate).
Hazardous waste in the right-of-way is another type ,of problem associated with road construction and
maintenance. Sometimes the problem is discovered when a major project unexpectedly runs into
hazardous waste during construction. The most common problems encountered by DOTs working in
the right-of-way are asbestos, underground storage tanks (USTs) (usually storing gasoline, diesel, or
other petroleum products), and other petroleum wastes, but the range of potential hazardous wastes
also includes organic and inorganic compounds, pesticides, cyanides, corrosives, and biological and
radioactive wastes (NCHRP, 1993). . ' •> :
Often, road maintenance facilities and operations are themselves the source of hazardous waste
problems due to the use of hazardous materials, such as lead paint, solvents, and pesticides, in
operations and maintenance activities. Some states track progress in replacing toxic products or
improving processes used in construction and maintenance (e.g., Washington) (SRI International
1993).
Lead-based paints were commonly used to paint bridges in the first half of this century; zinc-based
paints.have been used more recently. There is a potential for contaminant releases where toxic
substances are utilized during construction and maintenance. For example, heavy metals have been
found to create health and environmental problems, and elevated levels of lead have been discovered
in soils near bridges. Near the Golden Gate Bridge in San Francisco, highly contaminated sand and
soils were fenced off and closed to the public and then were removed or treated (Witt, 1995).
Many bridges with lead-based paint are undergoing lead abatement and recoating efforts. The
• Manhattan Bridge in New York City is the site of the largest lead abatement and recoating project in
the country, at a cost of $85 million (Greenman'et al., 1995). •
47
-------
Indicators of the Environmental Impacts of Transportation
It should be noted that construction of new capacity also may induce additional travel, which would
have environmental impacts as well. This indirect impact of construction is not considered here, since
the impacts of travel are considered in the section on travel.
CAUSAL FACTORS
• Level of construction activity
* Type and quantity of energy consumed during construction/maintenance activities
4 Emissions control technologies for plant and equipment
4 Quantity of hazardous material buried in the right of way and/or used in maintenance
operations and how it is managed when found
4 Topographical conditions (hills, valleys, etc.)
4 Climatic conditions (temperature, wind, rain, etc.)
4 Population density
• Local environmental resources/habitats
RELEASES OFDEICING COMPOUNDS
PRESENTATION OF INDICATORS
QwwrwEO OUTCOME/RESULTS INDICATORS
4 Typically, 5-10 percent of trees along heavily traveled roads are affected by road salt
application. Based on typical experiences in the states, salting of a hypothetical road could
kill 1 to 25 roadside trees per year, depending on the road's salt application rates and
proximity to trees (TRB, 1991).
4 In 1992, 17 states in the U.S. reported that road salting is a significant source of ground
water contamination, and four reported wetlands impacts from salinity (U.S. EPA, 1994b).
4 Four states report degraded wetlands integrity due to salinity (U.S. EPA, 1994b).
4 Salt was cited as a cause of 11 percent of impaired river miles in 1992 (U.S. EPA, 1994b).
States Reporting Degraded
Wetlands Integrity Due to Salinity
Impaired River Miles
12% by Salt
88% by Other Causes
Source: U.S. EPA, 1994b.
48
-------
The Indicators: Highway
* Specific outcomes, including wildlife habitat damage, reduced fish stocks, loss of unique
natural features, and corrosion damage to vehicles from increased salinity, are not quantified
nationally.
QUANTIFIED OUTPUT INDICATORS . .
+ No quantified data are available to estimate how much road salt enters groundwater, rivers,
and lakes.
QUANTIFIED ACTIVITY INDICATORS - • ,
> In the past decade, 10 million tons of rock salt have been applied in a typical year, but 1994
and 1995 applications were unusually high, as shown in the graph below (Salt Institute
1992).
Highway Deicing Salt Sales
(1940-1994)
1960
1980
2000
OTHER QUANTIFIED DATA AND LOCAL EXAMPLES
+ The cost of installing corrosion protection features during bridge deck construction and
maintenance will total between $125-$325 million per year during the next 10 years,
according to a TRB study. An equivalent amount will be spent on the protection and repair of
other affected bridge components, such as structural components exposed to salt from splash,
spray, and poor deck drainage (TR News, 1992).
4 A study of streams 50-100 meters downstream from a highway in New York State found
chloride concentrations up to 30 times higher than comparative upstream levels. Elevated
levels lasted for 6 months after termination of winter salt application (Demers and Sage
; 1990).
DESCRIPTION OF IMPACT '
Rock salt is the principal deicing agent used in winter road maintenance throughout the nation. The
use of road salt allows highway travel during snow conditions and is important for delivery of vital
goods and services (including emergency support vehicles which save lives) to large segments of the
country. Although salt is cheap and effective, it can cause adverse secondary effects. A recent
49
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Indicators of the Environmental Impacts of Transportation
literature review ranked the top three environmental impacts of road salt as (from most severe to
least): 1) effects on roadside vegetation, 2) harm to soil structure, and 3) impacts on drinking water
and aquatic life (TRB, 1991).
Road salt disintegrates pavements, corrodes auto bodies and bridges, pollutes groundwater, and alters
the water chemistry of nearby lakes, rivers, and wetlands. Freshwater plants are- often unable to
survive in wetlands areas that receive high quantities of salt-polluted runoff. The actual extent of
water contamination and habitat alteration per quantity of road salt used depend on highly site-
specific conditions such as watershed characteristics, amount of runoff and/or snowmelt, and type of
indigenous vegetation. The effect of'deicing runoff is not limited to roadside vegetation: 90 percent of
the salt applied to the street of Buffalo, NY, for example, enters into the city sewerage system and
then reaches Lake Ontario (Tolley, 1995).
Calcium magnesium acetate (CMA) has been developed as an environmentally benign, non-corrosive
alternative to road salt for deicing, but its application has been limited due to its higher price and
greater volume demands. To be effective, it must be applied early in a storm and used in quantities 20-
30 percent greater than salt. In addition, CMA is often less effective man salt in freezing rain, dry
snow, or light traffic; and it costs 10-25 percent more. And although widespread use of CMA might
reduce corrosion of motor vehicles and infrastructure components not already contaminated, its use
would have little effect on many older infrastructure components already contaminated by salt (TR
News, 1992). CMA has been extensively studied as an option (TRB, 1991).
CAUSAL FACTORS
* Amount of roadway deicing agent applied
* Type of deicing agent used
* Climate/weather conditions (amount of snow, ice, rainfall)
* Amount of high salinity runoff/snowmelt that reaches bodies of water (based on runoff
controls and local geography)
«• Depth of groundwater table
* Sensitivity of nearby habitats
HIGHWAY RUNOFF
PRESENTATION OF INDICATORS
QtMOTlfiCD OOrCOM£ff?ES£fl.7S INDICATORS
* In 1992, urban runoff contributed to the impairment of 11 percent of the nation's assessed
river miles, 24 percent of assessed lake acres, and 59 percent of assessed ocean shore miles.
It was cited as a major source of impairment for 5-15 percent of assessed surface water
bodies (U.S. EPA, 1994b). The exact contribution of transportation to urban runoff is not
known, but it is expected to be large, since road surfaces occupy a significant portion of land
in urban areas, 19 percent according to Tolley, 1995.
50
-------
The Indicators: Highway
Percentage Impaired by Urban Runoff
Assessed river miles
11%
Lakes Ocean shore miles
24% ^""~~T^fe^ 59%
Source: U.S. EPA, 1994b.
QUANTIFIED OUTPUT INDICATORS.
* Average pollutant concentrations of lead and copper in road runoff are more than twice as
great as those from residential and commercial areas (U.S. DOT, 1986; U.S. EPA, 1983).
* Pollutant concentration levels in highway runoff exceed concentrations from residential and
commercial areas (see table).
* Oil and grease in road runoff may total hundreds of thousands of tons per year (Apogee
estimate).39
39
Simply as an example to provide perspective, suppose that a meter of rainfall and water in the form of snow is
typical per year (not an unreasonable figure, at least for some parts of the country), this means that roughly a
meter of water falls on a square meter of pavement, or a volume of 1 cubic meter of water per year. If oil and
grease concentration in this water is 9 mg/1 as it runs off, the mass of oil and grease in this cubic meter would be
9 grams. This would equal almost a metric ton of oil and grease per year per 100,000 square meters of road
surface (a length of road 10 meters wide and 10 km long). Assuming roughly 3 meters width per lane'and
perhaps about 4 million paved lane-miles, there are approximately 20,000 square kilometers of paved road in the
U.o. - '
The above implies there could be 200,000 metric tons of oil and grease in road runoff annually nationwide if the
above assumptions were valid (actual average rainfall may be half as high). It is worth noting that this very crude
estimate corresponds to a scenario where the average U.S. vehicle (of which there are roughly 200 million) leaks
1 liter of oil and grease onto roads per year, or less than one tenth of a quart per month (assuming oil has the
density of water for simplicity here). This average rate of leakage seems at least plausible. It is also worth noting
that if such loadings are occurring, they are larger than estimated improper disposal of used motor oil and larger °
than reported air or water releases of many pollutants in auto manufacture.
5L
-------
Indicators of the Environmental Impacts of Transportation
Selected Road and Highway Storm Water Pollutant Concentrations
and Comparisons with Typical Runoff from Residential and Commercial Areas
Constituent
BOD (biological oxygen demand)
COD (chemical oxygen demand)
TKN (a measure of nitrogen)
Total Phosphate
Lead
Copper
Cadmium
Nickel
Oil and grease
PAHs (polycyclic aromatic hydrocarbons)
Pesticides/Herbicides
PCBs (polychlorinated biphenyls)
Road/Highway Runoff from Residential
Runoff Mean and Commercial Areas
Concentration (mg/1)
(mg/1)
24
160
3.0
0.9
4.3
0.19
0.02
5.0
9
4.6
0.03
0.335
12
94
2.3
0.5
0.24
0.053
-
-
-
'
"
Source: U.S. DOT, 1986; U.S. EPA, 1982 as cited in Weiss, 1993. Note: lead levels have dropped considerably
since these estimates were developed.
4 Highways have been found to contribute up to 50 percent of suspended solids, 16 percent of
hydrocarbons, and 75 percent of metals in some streams (Hamilton and Harrison, 1991).
Highway Contribution to Some Streams: Loading
Suspended solids Hydrocarbon Metal input
.»•••*""—IIlfete». ^—Tiiiife^
50% / 16% / ' 75%
Source: Hamilton and Harrison, 1991.
The impacts of runoff, of course, depend on many factors other than tons emitted. Oil and grease may
undergo biodegradation and dilution before they ever reach any body of water or sensitive ecosystem.
AcmnY INDICATORS
4 Roads occupy about 19 percent of the surface areas in large cities (Tolley, 1995).
* The percentage of roads in the U.S. that are paved has increased from about 27.3 percent in
1953 to 58.2 percent in 1993 (FHWA, 1994c).
52
-------
The Indicators: Highway
Total Road and Street Mileage in the United States
By Surface Type (1900-1993)
Soil Surfaced,
vel/Stone
1920
OTHER QUANTIFIED DATA AND LOCAL EXAMPLES
1940 1960 1980 1993
Source: FHWA, 1995c
Of the vehicle-related particulates in highway runoff, 37 percent come from tire wear, 37
percent from pavement wear, 18.5 percent from engine and brake wear, and 7.5 percent from
settleable exhaust (PEDCO as cited in Hamilton and Harris, 1991).
One study of runoff in California's Santa Clara Valley found that vehicles were the source of
67 percent of the zinc, 50 percent of the copper, and 50 percent of the cadmium found hi
runoff. (Santa Clara Valley Nonpoint Source Pollution Control Program as cited in Weiss,
1993) ,
In a study to assess the effects of highway construction on water quantity and quality in
creeks near construction in the Edwards aquifer (Texas) district, downstream concentrations
of total suspended solids below the right-of-way during construction of a highway in Texas
were roughly 10 times greater than before construction began. Flow rate in the creek nearby •
also increased significantly due to increased impermeable ground cover. Silt fences
sometimes used to control such sediment were found to be ineffective in the Texas study, and
problems were also seen in the expensive runoff control systems used (a sedimentation basin
and sand filter). (Barrett et al., 1995)
Over 50 percent of the annual pollutant loads in entering a section of the Pawtuxet River ,
adjacent to 1-95 in Rhode Island came from highway runoff (Hoffman, 1985). .
Investigations on a small Norwegian lake ecosystem found that the road had no effects on
oxygen condition but considerable effects on conductivity and high concentrations of
cadmium, zinc, sodium, and chloride. Also the diversity and abundance of the benthic
communities near the highway were reduced relative to a control location (Baekken, 1994).
53
-------
Indicators of the Environmental Impacts of Transportation
DESCRIPTION OF IMPACT
Highway contaminants are deposited on roadway surfaces, median areas, and rights-of-way from
atmospheric fallout, fuel combustion processes, lubrication system losses, tire and brake wear,
transportation load losses, deicing agents, and paint from infrastructure. During storm events,
rainwater first washes out atmospheric pollutants and, upon surface impact (or snowmelt), picks up
roadway deposits, and runs off into receiving water bodies. This highway runoff can be highly
polluted and have negative impacts—such as sedimentation, eutrophication, accumulation of
pollutants in sediments and benthic organisms, and destruction of native species—on receiving
waters.
Runoff from roads is affected by both the amount and type of infrastructure (paved or unpaved
surfaces), as well as by the amount of travel.40 Whether the road is paved or not has a great effect on
runoff. Pavement and structures may cover soils and destroy vegetation that would otherwise slow
and absorb runoff before it reaches receiving bodies of water. The graph above shows that while road
mileage has not been growing especially quickly, paved mileage has been growing very rapidly. This
has implications for increased runoff impacts, but also has other implications, such as reduced
particulate emissions from reentrained dust and perhaps higher speeds of travel and greater emissions
per VMT for certain pollutants. Although these tradeoffs are not discussed further here, the trend in
paved mileage is notable.
FHWA research in the 1970s on highway runoff water quality found that runoff had significant
effects only from highways with traffic volumes greater than 30,000 vehicles per day (major freeways
and urban arterials). Average daily traffic (ADT) has a strong influence on the quality of stormwater
as it leaves the highway; because ADT levels are higher in urban areas than rural locations, pollutant
levels in highway runoff are higher in urban areas.
The impacts and significance of roadway runoff are highly site-specific. The quantity of runoff
generated depends on the frequency, intensity, and duration of precipitation in an area. The water
quality characteristics of runoff are affected by local air quality (because of deposition of air
pollutants onto roads) and, to some extent, the level of traffic activity. The quantity of pollutants
originating from highways and motor vehicles, however, is not well understood as pollutants are hard
to measure and vary by location.
Pollutants found in runoff are generally classified under six broad categories: suspended solids or
particulates, oxygen-consuming constituents (BOD, COD), nutrients, heavy metals, trace organics,
and microorganisms. Direct vehicle deposits are a major source of particulates and heavy metals:
settleable exhaust, copper from brake pads, tire and asphalt wear deposits, and drips of oil, grease,
antifreeze, hydraulic fluids, and cleaning agents. An estimated 46 percent of vehicles on U.S. roads
leak hazardous fluids (AAMA, 1990). Indirectly, vehicles also contribute by carrying solids from
parking lots, urban roadways, construction sites, farms, and dirt roads. More than 95 percent of the
solids on roadways originate from sources other than the vehicles themselves (Barrett et al., 1993).
Secondary runoff pollutant sources associated with vehicular traffic include gas stations and other
auto-related facilities, oil production and transportation operations, petroleum refineries, and
improper disposal of used motor oil. Nitrogen and phosphorus-based nutrients generally originate
from atmospheric and roadside fertilizer applications. Atmospheric deposition is the main source of
PCBs.
40 Note that this impact is discussed here alone rather than in both this section and the road vehicle travel section.
54
-------
The Indicators: Highway
These pollutants can harm the environment in various ways. Oxygen consumption (from high BOD)
harms aquatic life, while nutrients cause eutrophication, where excess aquatic plant growth can block
sunlight, also harming aquatic life. Toxic substances can affect human health or various plant of
animal species.
CAUSAL FACTORS
* Level of traffic activity: .the number of vehicles during a storm event (VPS) is a better
determinant of pollutant loading than the average daily traffic (ADT) or antecedent dry
period (Barrett et al., 1993). DQT considers impacts negligible on roads with less than
30,000 ADT. Levels over 30,000 ADT are not very common outside urban areas, though
some roads surpass 200,000 ADT.
* Rate of deposition of contaminants on road surface per vehicle
* Paved surface area (see graphic on growth in paved surface above)
* Precipitation activity: antecedent dry period, storm intensity and duration, total amount of
ramfall/snowmelt
* Drainage characteristics
> *• Ecology and other aspects of receiving water bodies: type, size, diversity, potential for
dispersion
* Toxicity and chemical/physical characteristics of pollutants
55
-------
-------
The Indicators: Highway
2. MOTOR VEHICLE AND PARTS MANUFACTURE
The manufacture of motor vehicles and parts results in environmental impacts through the release of
toxics and other pollutants to the air, soil, and water.
Toxic Releases and
Other Emissions
TOXIC RELEASES AND OTHER EMISSIONS
PRESENTATION OF INDICATORS
QUANTIFIED OUTCOME/RESULTS INDICATORS
No quantified data on human health impacts, such as increased incidence of cancer from
toxics, or habitat and species impacts are available.
QUANTIFIED OUTPUT INDICATORS
4 114.5 million pounds (or about 57,000 tons) of toxic chemicals were reported released on-
site from vehicle manufacturing facilities in 1993 (see table).41
41 Note that these figures do not include impacts of equipment and parts manufactured outside the U.S. but do
count impacts of exported U.S. products.
57
-------
Indicators of the Environmental Impacts of Transportation
Toxic Chemicals Released from Vehicle Manufacturing Facilities and Related Sources
(Pounds per Year)
SIC
Code
3711
3713
3714
3715
3716
3537
3751
4213
5013
Industry Type
Motor Vehicles &
Passenger Car Bodies
Truck & Bus Bodies
Motor Vehicle Parts
& Accessories
Truck Trailers
Motor Homes
Industrial Trucks,
Tractors, Trailers &
Stackers
Motorcycles, Bicycles
& Parts
Trucking (No Local)
Wholesale-Motor
Vehicle Supplies &
New Parts
TOTAL HIGHWAY
VEHICLES
Air
52,878,028
12,977,951
34,540,544
2,522,371
2,680,082
561,110
6,740,758
56,763
12,259
112,969,866
On-Site Releases
Water Land
3,038
3,916
147,394
27
,
10
8,209 .
60
162,654
255
3,983
1,348,978
1,500
-
5
.
10
-
1,354,731
Total
52,881,321
12,985,850
36,036,916
2,523,898
2,680,082
561,125
6,748,967
56,773
.12,319
114,487,251
POTW
Transfer
2,519,072
260,887
890,432
1,894
250
10,000
3,029
_
-
.. 3,685,564
Off-Site
Locations
Transfer
51,603,667
15,907,099
112,999,744
6,223,948
395,759
672,320
6,033,915
27,705
7,075,069
200,959,226
Source: Toxic Releases Inventory, 1993
POTW = Publicly owned treatment works
SIC = Standard Industrial Classification
* About 33 percent of the industry's TRI wastes were managed through on-site recycling,
energy recover}', or treatment rather than being released or transferred in 1993 (U.S. EPA,
1995b).
* In 1993, 609 facilities reported TRI releases in the motor vehicle manufacturing industry
(only large facilities are required to report), and the average facility reported 130,000 pounds
(65 tons) of toxic releases.
58
-------
The Indicators: Highway
Vehicle Manufacturing Industry's Contribution to:
GNP
, 4.0%
Toxic Release
Inventory
4.3%
Toxic Releases
to Air Only
6.8%
Priority
Pollutants
0.3%
The motor vehicles, bodies, parts, and accessories industries also emit the following
quantities of other pollutants per year:
Other Emissions from Vehicle Manufacturing Facilities
Pollutant
•
CO
N02
PM-10
TP
S02-
VOC
Short tons per
year emitted in
these
industries
• 35,303
23,725
2,406
12,853
25,462
101,275 '
U.S. total for all
industries
97,208,000
23,402,000
45,489,000
7,836,000
21,888,000
23,312,000
Percentage^ total
for all industries
0.04%
0.10%
0.01%
0.16%
0.12%
0.43%
Source: U.S. EPA, Office of Air and Radiation, AIRS Database, May 1995.
* It is noteworthy that emissions from vehicle travel are much higher than emissions from
vehicle manufacture, at least for several key pollutants.
OTHER QUANTIFIED DATA AND LOCAL EXAMPLES .
4 ' One General Motors assembly plant has reduced packaging.waste going to landfills per
vehicle to less than one pound per vehicle (U.S. EPA, 1995b).
DESCRIPTION OF IMPACT
The motor vehicle and equipment industry is the largest manufacturing industry in North America,
accounting for about 4 percent of gross national product (GNP). There are approximately 4,467 motor
vehicle and equipment facilities in the U.S., 3-9 percent of which are in the Great Lakes Region (U.S.
EPA,1995b).
The manufacture of automobiles, trucks, and other road vehicles involves the use of a variety of
materials and chemicals. During the manufacturing process, toxic chemicals are released from vehicle
manufacturing facilities into the environment. Releases occur as on-site discharges of toxic chemicals,
59
-------
Indicators of the Environmental Impacts of Transportation
including emissions to the air, discharges to water, releases to land, and contained disposal or
injection underground. Chemicals are transferred off-site when they are shipped to other locations, as
the following diagram shows.
On-Site Emissions
Air
Land
Off-Site
Transfers
Water
Underground
Injection
On-site releases to air occur as either stack emissions, through confined air streams such as stacks or
vents, or fugitive emissions, which include equipment leaks, evaporative losses from surface
impoundments and spills, and releases from building ventilation systems. Surface water releases
occur through process and treatment discharge pipes, as well as diffuse runoff from the plant site.
Releases to land may result from landfills, surface impoundments, and other types of land disposal
within the boundaries of the reporting facility. Underground injection is a contained release of a fluid
into a subsurface well for the purpose of waste disposal.
Off-site transfers represent a movement of the material or chemical away from the reporting facility.
However, except for off-site transfers for disposal, these quantities do not necessarily represent entry
of the chemical into the environment. Chemicals are often shipped to other locations for recycling,
energy recovery, or treatment. In many cases, transfers are to publicly owned treatment works
(POTWs). Wastewaters are transferred through pipes or sewers to a POTW, where treatment or
removal of a material or chemical from the water depends upon the nature of the chemical and
treatment methods used. Some chemicals are destroyed in treatment. Others evaporate into the
atmosphere. Some are removed but are not destroyed by treatment and may be disposed of in landfills
(U.S. EPA, 1992).
The top five toxic pollutants (by volume) reported released include xylene, glycol ethers, toluene,
methyl isobutyl ketone, and N-butyl alcohol These are solvents used to clean equipment and metal
parts and used in many coatings and finishes (U.S. EPA, 1995b). It should also be noted that the
industry has reduced toxic releases considerably in the recent years.
Other non-toxic air pollutant are emitted by the motor vehicle manufacturing industry, such as carbon
monoxide (CO), particulate matter (PM), and volatile organic compounds (VOCs). These pollutants
can cause human health effects, as well as materials damage and visibility degradation.
60
-------
The Indicators: Highway
CAUSAL FACTORS
* Number of vehicles built '
* Amount of, chemicals used per vehicle
4 Efficiency of controls and'efforts to reuse or recycle chemicals, including pollution
prevention *
* Amount of chemicals transferred to other locations for recycling, energy recovery, or
treatment
* Types of chemicals released and toxicity
* Population density and extent of exposure
4 Environmental conditions such as climate, topography, or hydrogeology affecting fate and
transport of chemicals in the environment
61
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The Indicators: Highway
3. ROAD VEHICLE TRAVEL
Road vehicle travel is the dominant form of transportation in the United States. About 2.3 trillion
vehicle miles were traveled on U.S. roads in 1994 by passenger cars, motorcycles, buses, light-duty
trucks, and heavy-duty trucks (FHWA, 1995d). Vehicle travel has a number of environmental effects.
Vehicles emit air pollutants from their exhaust, evaporation, use of air conditioners, as well a's
fugitive dust which is stirred up from the road surface by automobiles. In addition, vehicles create
noise, and strike and kill animals that attempt to cross roadways. Hazardous materials incidents may
release harmful chemicals to the environment.
These impacts are discussed below. For all of these impacts, data on travel is an activity indicator
that provides a crude indication of environmental damage. Information on vehicle travel activity is
presented in Appendix A.
Tailpipe and
Evaporative
Emissions
Emissions of
Refrigerant
Agents from Air
Conditioners
HAZMAT Spills
Roadkill
TAILPIPE AND EVAPORATIVE EMISSIONS
PRESENTATION OF INDICATORS
QUANTIFIED OUTCOME/RESULTS INDICATORS . •
* Air pollution from highways caused a significant number of health effects in 1991 (these
estimates include health impacts from travel, road dust, and upstream activities) (McCubbin
and Delucchi, 1995):
•f Approximately 20,000-46,000 cases of chronic respiratory illness (chronic cough,
phlegm, wheezing, chest illness, and bronchitis)
* Roughly 50-70 million respiratory-related restricted activity days (RRADs), of which
about 43-60 million of these can be attributed to particulate matter alone
* An estimated 530 cases of cancer from air toxics associated with highway use. Estimates
of cancer risk, however, are highly uncertain. Various estimates have attributed 50 to
63
-------
Indicators of the Environmental Impacts of Transportation
19,000 cancer deaths per year to carcinogens from motor vehicle emissions (U.S. EPA,
1993c). Much of this uncertainty is over the carcinogenicity of diesel particulate matter.
Heavy duty diesel trucks account for perhaps 25 percent to almost 100 percent of the
cancer risk from motor vehicles (U.S. EPA, 1989a).
* About 852 million headaches from CO associated with motor vehicle use.
* An estimated 40,000 premature deaths in the U.S.—of which 33,300 can be attributed to
particulate matter—a number comparable to the number of deaths from motor vehicle
accidents.
Comparison of Estimated Mortality, 1991
CO
JC
OS
CD
Q
*5
CO
"i
CO
CO
o
H
Motor Vehicle Motor Vehicle
Accidents Air Pollution
Source: Motor vehicle estimate from McCubbin and Delucchi, 1995.
Impacts on plants and animals, including forests and crops, have generally not been
quantified.
OUTPUT INDICATORS
* In 1994, highway vehicle operations were responsible for the following emissions
nationwide (U.S. EPA, 1995e):
40-
30-
20-
10-
n -
f, s
Ozone
Particulates
(includes road dust)
Pollutant
Quantity Emitted
(1994, thousand
short tons )
Percentage of total
Emissions of that
Pollutant42
Carbon Monoxide (CO)
Nitrogen Oxides (NO*)
Volatile Organic Compounds
(VOCs)
Sulfur Dioxide (SO2)
Particulate Matter (PM-10)
Lead (Pb)
61,070
7,530
6,295
295
311
1.4
' 62.3%
31.9%
27.2%
1.4%
0.7% •
28.3%
42
Note: percentages are based on anthropogenic emissions, except for PM-10, which includes natural emissions.
64
-------
The Indicators: Highway
Highway Share of Air Pollutants Emitted, 1994
CO emissions
38%
Other
62%
From
vehicles
VOC emissions
73%
Other
27%
From
vehicles
NOX emissions
68%
Other 1
32%
From
vehicles
Pb emissions
62%
Other
28%
From
vehicles
In 1993, CO2 emissions from highway vehicle operations accounted for approximately 320
million metric tons of carbon equivalent (mmtCe), or 23percent of total national
anthropomorphic CO2 emissions (Apogee estimate).43
Highway vehicle travel contributed to emissions of other greenhouse gases, as reported
below (U.S. EPA, 1994a):
Pollutant
Quantity Emitted
(1990, thousand
metric tons)
Methane
Nitrous Oxide (N2O)
201
87
In 1990, highway vehicle operations were responsible for the following emissions of toxics
(U.S. EPA, 1995e): .
Pollutant
Benzene
Butadiene
Formaldehyde
Quantity Emitted
(1990, short tons)
217,765
41,883
101,722
Percent of total
Emissions of that
Pollutant
45% -
41%
37%
'.•>•• ' .
43 Estimate is based on the following methodology: transportation sector energy use by fuel type within a mode
(DOE/EIA, 1995b) was multiplied by carbon coefficients (mmtCe/quadriliion Btu) for each.fuel (DOE/EIA,
1995a), then adjusted by fraction of carbon that does not oxidize during combustion (DOE/EIA, 1995a). Note
.that this estimate does not account for upstream emissions, such as emissions from car assembly and fuel
production; refer to DeLuchi, 1991, for carbon coefficients needed to compute total fuel-cycle CO2 emissions.
65
-------
Indicators of the Environmental Impacts of Transportation
Highway Share of Toxics Emitted, 1990
BENZENE
45%
From
Vehicles
BUTADIENE
41%
From
Vehicles
FORMALDAHYDE
37%
From
Vehicles
The share of total emissions attributable to on-road mobile sources varies greatly by location:
the share of NOX can range from 20 to 60 percent of total (not only 'anthropogenic) emissions
in most ozone nonattainment areas, and on-road VOC emissions can range from 10 to 40
percent of the total (Apogee, 1996).
CO Emissions from Highway Vehicles
Year Thousand Percentage of
Short Tons Total CO
Emissions
CO Emissions
1940
1950
1960
1970
1980
1985
1986
1987
1988
1989
1990
1991
1992
1993
1994
30,121
45,196
64,266
88,034
78,049
77,387
73,347
71,250
71,081
66,050
62,858
62,074
59,859
59,989
61,070
32.2
44.0
58.6
68.7
67.5
67.5
67.2
66.0
61.4
64.0
62.5
63.7
63.7
63.T
62.3
CO
c
°
•c
o
.c
W
T3
C
CB
in
=]
O
jr
90,000
80,000
/'O.OOO
60,000
50,000
40,000
30,000
20,000
10,000
1940
2000
Source: U.S. EPA, 1995e.
-------
The Indicators: Highway
NOX Emissions from Highway Vehicles
Year
1940
1950
1960
1970
1980
1985
1986
1987
1988
1989
1990
1991
1992
1993
1994
Thousand Percentage of
Short Tons Total NOX NOX Emissions
.'Emissions
1 lin ion 9000
JL,JJU lo.U j,uwu j ,
2,143 21.2 8,000 . . / "\
3,982 28.2 • „ 7,000 •" ./ ^~
7,390 35.8 |. 6.000 . '•/"•' " "
8,621 37.0 5 Klm /.
8,089 35.4 » ' /
7,773 34.8 § """" /
7,651 34.2 1 ^.
7,682 33.1 1'000
7 'IBS ^° 5 - •
7,373 32.5 ' 194° 196° 1980 2000
7,440 32.6 . , Year
7,510 32.3
7,530 31.9 .
Source: U.S. EPA, 1995e. .
VOC Emissions from Highway Vehicles
Year
1940
1950
1960
1970
1980
1985
1986
1987
1988
1989
1990
1991
1992
1993
1994
Thousand Percentage.of
Short Tons total VOC VOC Emissions
, Emissions
/I C17 10 1 i/] goo
7,251 34.6 10QOO /\
10,506 43.0 ^ X \
12,972 42.3 ' o 1o,ooo / , V
8,979 34.7 r cnnn / ^ \
9,376 36.3 « ' / \
8,874 35.5 1 6.°°° X x'
. ' 8,477 34.2 § A nnn '
.8,290 32.2 £••'••.
7,192 30.0 2'°°°
6,854 29.0
6,499 28.4 1940 1960 1980 2000
6,072 27.1
6,103 27.0
6,295 27.2 •- •- •• -. -- - '
Source: U.S. EPA, 1995e
67
-------
Indicators of the Environmental Impacts of Transportation
Emissions from Highway Vehicles
Year Thousand Percentage of
Short Tons Total SO2
.'' ] ' ' '-''"-'.'. - Emissions
SO2 Emissions
1940
1950
1960
1970
1980
1985
1986
1987
1988
1989
1990
1991
1992
1993
1994
3
103
114
411
521
522
527
538
553
570
571
570
578
517
295
0.0
0.5
0.5
1.3
2.0
2.2
2.3
2.4
2.4
2.5
2.5
2.6
2.6
2.4
1.4
600
1960
1980
2000
Year
Source: U.S. EPA, 1995e
Direct Particulate Matter (PM-10) Emissions from Highway Vehicles44
Year Thousand Percentage of
Short Tons Total PM-10
Emissions
Particulate (PM) Emissions
1940
1950
1960
1970
1980
1985
1986
1987
1988
1989
1990
1991
1992
1993
1994
210
314
554
443
397
363
356
360
369
367
357
349
343
321
311
-
-
-
-
-
0.81%
0.71%
0.86%
0.61%
0.70%
0.82%
0.71%
0.78%
0.75%
0.68%
•c
o
CO
CO
Cfl
I
600
500
400 -
300
200
100
1940
1960
1980
2000
Year
Source: U.S. EPA, 1995e
44 Percentage of total emissions are not reported for paniculate matter prior to 1985 because of changes in total
emissions inventories; fugitive dust and wind erosion are reported only for the period 1985 to 1994.
68
-------
The Indicators: Highway
Lead Emissions from Highway Vehicles
Year Short Tons Percentage of
TotalPb
Emissions
1970
1975
1980
1985
1986
1987
1988
1989
. 1990
1991
1992
1993
1994
171,961
130,206
: 62,189,
15,978
3,589
3,121
2,700
2,161 •
1,690
1,519
1,444 .
1,401
1,403
78.4
82.1
83.0
79.4
49.2
45.5
41.5
35.8
29.8
28.8
, 29.5
28.4
28.3
01
I
I
W
Lead Emissions
1970 1975 1980 1985 1990 1995
Year
Source: U.S. EPA, 1995e
It is important to note that there is considerable uncertainty regarding the values of the emissions
statistics used for these output indicators. Since actual measurement of all vehicle emissions is
impractical, the emissions estimates come from models which are based on travel data, speeds,
vehicle fleet characteristics, and other variables, and emissions factors. These models are updated
over time, and thus, historical data from different years are not comparable if based on different
methodologies. For example, EPA reports 1990 CO emissions from highway vehicles as 59,801
thousand short tons in their National Air Pollutant Emission Trends, 1990-1992 report, and as 62,858
thousand short tons in their more recent National Air Pollutant Emission Trends, 1993 report.
There is some evidence that air pollution can have a significant impact on water quality. Not all
atmospheric deposition results from motor vehicle emissions, but some statistics on such pollution at
least provide a sense of how air pollution impacts surface waters45:
4 Estimates of atmospheric nitrogen input to water bodies such as the Chesapeake Bay and
other major east coast estuaries range from 5 percent to 50 percent of the controllable load of
nitrogen (most estimates are in the range of 30 percent). The error in such estimates, . '
however, is cited as at least plus or minus 20 percent and up to a factor of two or three,
depending on location and pollutant considered. • . '
4 Atmospheric loadings of metals to water bodies such as the Chesapeake Bay may range from
- over 95 percent of total loadings in the case of lead to about 10 percent in the case of
cadmium.
- 4 Annual fluxes from wet deposition reported at various coastal locations range from under 5
. mg per square meter for copper, nickel, and lead to 15-30 mg per square meter for iron and
zinc. •
45
Air deposition data from AQCG/STAG 1994/95, and Valigura et al., 1994/95
69
-------
Indicators of the Environmental Impacts of Transportation
Wet deposition of various polycyclic aromatic hydrocarbons such as benzo[ghi]perylene
(including some carcinogenic products of incomplete combustion) are in the range of 1-10
micrograms per square meter per year.
ACTIVITY INDICATORS
* Refer to Appendix A for data on vehicle travel.
DESCRIPTION OF IMPACT
Air pollution is generally considered the main environmental impact of motor vehicle transportation.
During the combustion process, automotive engines emit several types of pollutants, including:
carbon monoxide (CO), sulfur oxides (SOx), nitrogen oxides (NOX), volatile organic compounds and
other hydrocarbons (VOCs/HCs), particulate matter (PM), and carbon dioxide (CO2). These pollutants
affect the environment, health, and welfare by causing respiratory and other illnesses, reduced
visibility, and soiling and corrosion of materials. They also affect the environment by causing adverse
effects on ecosystems including damage to crops, forests, and other terrestrial and aquatic plants and
animals. Although CC^is not harmful to human health or habitat directly, it is important as a
greenhouse gas that contributes to global warming.
Certain chemicals interact in the air to form secondary pollutants. Ozone is one key secondary
pollutant, formed by the combination of NOX and VOCs. In addition, the combination of sunlight,
water, and chemicals like SO2, NOX, and HCs can form secondary particulate matter, as the diagram
below shows.
Highway vehicles emit pollutants into the atmosphere during start-up (especially during a cold start),
travel, and cooling down (hot-soak emissions). Pollution from highway vehicles comes from
byproducts of fossil fuel combustion process (exhaust) and from evaporation of the fuel itself. In the
first few minutes of a trip, emissions are higher because the emissions control equipment has not yet
reached its optimal operating temperature.
In addition, pollutants escape into the air through fuel evaporation. With efficient exhaust emission
controls and gasoline formulations, evaporative losses can account for a majority of the pollution
from current model cars on hot days. Evaporative emissions include diurnal emissions (as
temperature rises during the day, the fuel tank heats and vents gasoline vapors), running losses
(vaporization of gasoline during car operations), hot-soak emissions (gasoline evaporation that
continues after a vehicle is parked since the engine remains hot for a period of time), or refueling
losses (vapors escape when the tank is filled).46
46 Losses from refueling are counted as stationary^ource emissions by EPA's Office of A:r Quality and Planning
Standards, but can be modeled separately in the MOBILE model.
70
-------
The Indicators: Highway
Primary
Pollutants
Secondary
' Particulates
Pafficulates,
CAUSAL FACTORS
* Number of vehicle trips: number of cold-starts, hot-starts, hot-soaks
* Vehicle miles of travel (VMT)
Vehicle type, age, weight, and emissions control technology
Type of fuel consumed (gasoline, diesel fuel, etc.)
Travel characteristics: speed, acceleration, etc. affects emissions per mile
•
•
•
The above factors work in combination to influence the total amount of pollution emitted, as the
following diagram shows:
Emissions per cow-start, •
hot-soak by chemical
Emissions
by chemical
Vehicle type, age, and
emissions control
technology
Travel Conditions
(Speed, etc.)
Emissions per gallon
fuel consumed
For example, travel conditions and vehicle type together influence fuel efficiency (gallons of fuel
consumed per mile) and pollutant emissions rates. Typically, faster speeds tend to reduce emissions
per mile, although for some pollutants, emission rates begin to increase once again when travel speeds
exceed a certain level. Meanwhile, different types of vehicles (e.g., gasoline powered automobiles
and diesel trucks) emit different amounts of pollution at any given speed. Some factors, like
population demographics, influence the level of travel, and thus, indirectly affect emissions levels.
71
-------
Indicators of the Environmental Impacts of Transportation
Factors that influence the amount of environmental damage that occurs from air pollutant emissions
include:
4 Topographical conditions (hills, valleys, etc.) affects dispersion/dilution of pollutants
* Climatic conditions (temperature, wind, rain, etc.) affects dispersion/dilution of pollutants
and formation of secondary pollutants
4 Population density affects number of people exposed to pollution
* Sensitivity of local ecosystems
Topographical
Climate/ \
Meteorological >
Conditions v.
VrxHint, <
Emffl
Transj
jfPoMulante
aortation
/
Amount, of F
Emitted f
Other Soi
\
Population
Density
. Level of Outdoor
\ Activity
v\
V
^ Ambient Air
/Pollutant Levels
it i 1 Ecosvstem and
OllUtant L-woyoiciu cwju.
rom Cr°PTyPe
rces and Density
Locally
h
N,
^-A.
Human
Exposure to
Pollutant
Materials
Exposure to •
Pollutant
Ecosystem and
Crop Exposure
to Pollutant
^
^
^~
^-~
Health Impacts
(Mortality/Morbidity)
Materials
Damage
Ecosystem and
Agriculture
Damage
Global Warming
.' Potential
FUGITIVE DUST EMISSIONS FROM ROADS
PRESENTATION OF INDICATORS
QtMOTJREO OUTCOUe/RSSULTS INDICATORS
* Paniculate matter associated with motor vehicle use was responsible for approximately
33,300 deaths (see graphic on particulate-related mortality in emissions section above);
between 17,700 and 41,600 cases of chronic respiratory illness; 1.12 million asthma attacks;
and between 42.9 and 59.9 million respiratory restricted activity days (RRADs) in 1991
(McCubbin and Delucchi, 1995). Of these impacts, road dust is responsible for the great
majority, since road dust constitutes about 98 percent of particulate matter associated with
motor vehicles (calculated from U.S. EPA, 1995e).
* Quantified national data on materials damage (soiling of buildings) and visibility degradation
from road dust are not readily available.
QuwnflED OUTPUT INDICATORS
* Fugitive dust from highways constituted 32.0 million short tons of particulate matter (PM-
10) released into the air in 1994 (see table).
4 Fugitive dust from highways accounts for about 40percent of particulate matter emissions.
72
-------
The Indicators: Highway
Fugitive Dust Contribution to National PM-10 Emissions, 1994
Source Quantity Percentage of Percentage of
Emitted total fugitive total PM-10
(thousand short dust
tons)
Unpaved Roads
Paved Roads
Other
Total Fugitive-Dust
Total All Particulates
(PM-10) , '
12,883
6,358
12,771
32,012
45,431
40%
20%
40%
100%
-
25%
14%
28%
70%
100%
Source: U.S. EPA, 1995e
Fugitive Dust Emissions (PM-10), Historical
Year Thousand Short Tons
Unpaved Roads Paved Roads
1985
11,644
5,080
1986
11,673
5,262
1987
•11,110
5,530
1988
12,379
5,900
1989
11,798
5,769
1990
11,338
5,992
1991
11,873
5,969
1992
11,540
5,942
1993
12,482
6,095"
1994
12,883
6,358
Source: U.S. EPA, 1995e
Fugitive Dust Emissions from Roads
in
c
o
I--
o
w
^
c
co
01
3
0
14 000
12,000
10,000
8,000
6,000
4,000
2,000
— ^— '
„- — — «-— ~*'"*~" '
"-: "r
Roads
—
ads i
0 •*-
1984 1986
1988 1990
Year
1992 1994
QUANTIFIED ACTIVITY INDICATORS
* Refer to Appendix A for data on vehicle travel.
DESCRIPTION OF IMPACT
Fugitive dust from travel on roads constitutes a significant portion of national PM-10 emissions,
which in turn contribute to total suspended paniculate matter in air. Dust generated from road travel is
called "fugitive" because it does not enter the atmosphere in a confined flow stream. Two sources of
dust are important to consider when evaluating the environmental impacts of road travel: paved and
uhpavedroads. ' ' •
The quantity of dust emissions from a given section o.f unpaved road varies roughly linearly with the
volume of traffic. When a vehicle traverses a segment of unpaved road, the force of the wheels on the
road surface causes pulverization of surface material. Particles are lifted and dropped from the rolling
wheels, and the road surface is exposed to strong air currents in turbulent shear with the surface. The
turbulent wake behind the vehicle continues to act on the surface after the vehicle has passed.
73
-------
Indicators of the Environmental Impacts of Transportation
Fugitive dust from paved roads consists primarily of mineral matter, similar to common sand and soil,
mostly tracked or deposited onto the roadway by vehicle traffic itself. Vehicle carryout from unpaved
areas is probably the largest single source of street deposit. Other particulate matter is emitted directly
by the vehicles from engine exhaust, wear of bearings and brake linings, and abrasion of tires against
the road surface. f
Although unpaved roads recently comprised about 42 percent of total road mileage in the U.S., they
accounted for 64 percent of the fugitive dust from travel on roads in 1993. It is notable that paved
road mileage has been growing rapidly, as existing roads are paved at a much higher rate than new
roads are built. As recently as around 1980, unpaved mileage exceeded paved mileage.
CAUSAL FACTORS
4 Lane mileage, paved and unpaved
4 VMT, by pavement type
4 Topographical conditions (hills, valleys, etc.) affecting pollutant dispersion
4 Climatic conditions (temperature, wind, rain, etc.) affecting pollutant dispersion and
secondary pollutant formation
4 Population density affecting potential exposure
EMISSIONS OF REFRIGERANT AGENTS FROM VEHICLE AIR CONDITIONERS
PRESENTATION OF INDICATORS
Qwmw OUTCOME/RESULTS ImicATORS
4 Quantified data on the contribution of vehicle refrigerant agents to depletion of the ozone
layer and global warming are not available.
t
QUANTIFIED OUTPUT INDICATORS
4 Nationwide, leaky vehicle air conditioners are responsible for 25 percent of all CFC
emissions (Washington, 1991).
4 71,000 metric tons of CFC-12 were released in 1994 from all sources (not only vehicles)
(DOE, 1995a) ( see table).
Estimated U.S. Emissions of CFC-12 and HFC-134a (all sources), 1987-1994
(thousand metric tons of gas)
Gas
CFC-12
HFC-134a
1987
110
NA
1988
110-
NA
1989
114
NA
1990
112
1
1991
108
1
1992
102
3
1993
99
6
1994
71
10
Source: DOE, 1995a.
74
-------
The Indicators: Highway
QUANTIFIED ACTIVITY INDICATORS
4 U.S. autos were responsible for approximately 175 million pounds of CFCs consumed in
1989 of 700 million total (NRDC, 1993). As of 1996, CFCs are no longer being produced.
DESCRIPTION OF IMPACT
Automobile air conditioners are subject to significant leakage, with nearly all of the refrigerant
leaking out over a 5-year time period. Until recently, the chlorofluorocarbon CFC-12 has been the
principal refrigerant agent used in automobile air conditioners. Other major end uses of CFC-12
include commercial air conditioning, refrigeration (refrigerators and freezers), and as a blowing agent
for foams, insulation, and packaging. CFCs are potent greenhouse gases. (U.S. DOE 1995a)
CFCs are currently being phased out because they damage the stratospheric ozone layer. By signing
the Montreal Protocol on Substances that Deplete the Ozone Layer and Copenhagen Amendments, the
U.S. committed to eliminating the production of all CFCs by January 1, 1996. Stratospheric ozone,
beneficial for its ability to absorb ultraviolet radiation, is, however, also a greenhouse gas. Gases that
destroy stratospheric ozone thus have indirect cooling effects. Chlorine-containing chemicals such as
CFCs tend to react with ozone, and the net effect on global climate is ambiguous (U.S. DOE, 1994b).
Hydrofluorocarbon HFC-134a became the standard automobile air conditioner refrigerant in 1994,
and HFC emissions will grow rapidly as CFCs gradually disappear from the automobile fleet. HFCs,
which contain no chlorine, have no effect on ozone and simply are unambiguously greenhouse gases.
Automobile air conditioners are the principal end-use for HFC-134a. In 1993, Ford sold nearly 40,000
vehicles that each used about 2 pounds of HFC-134a in their air conditioners. Previous models used
about 2.5 pounds of CFC-12. As of 1994, practically all new automobiles were using HFC-134a as
the refrigerant in their air conditioners, and many manufacturers now offer conversion packages
through their dealerships (DOE, 1994b). .
CFC-12 has a atmospheric lifetime of 102 years, and one molecule of CFC-12 has a 100 year global •
warming potential 8,500 times that of one molecule of CO2. HFC-134a has a lifetime of 14 years. One
molecule of HFC-134a has a 100-year global warming potential 1,300 times that of one molecule of
CO2. But the lack of chlorine in HFCs and their shorter atmospheric lifetimes reduce the indirect
cooling effects of CFCs. Thus, HFC replacement compounds may be worse from a global climate
perspective than their predecessors.
The outcome is affected directly by output of CFCs. It does not depend on climate, geography,
exposure by humans or habitat, or other factors. Location will influence air-conditioner use since
areas with high temperatures will tend to emit more CFCs. However, in this case location is a causal
•factor for the emissions, not a factor that influences the outcome of the emissions.
CAUSAL FACTORS
* Quantity of refrigerant agent used
4 Net global warming potential of refrigerant agent used
* Net ozone depleting potential of refrigerant agent used
75
-------
Indicators of the Environmental Impacts of Transportation
NOISE
PRESENTATION OF INDICATORS
QwwjFfeo OUTCOME/RESULTS INDICATORS
• 4 37.0 percent of the U.S. population was exposed to noise levels from road transport great
enough to cause annoyance—defined as Leq greater than 55dB(A)—in 1980 (OECD, 1993).
A more recent estimate is not available.
4 Significant portions of the U.S. population were exposed to daily noise levels from road
transport great enough to cause other effects, such as communication interference,
muscle/gland reaction, and changed motor coordination, as the following chart shows:
Percent of U.S. Population Exposed to Road Transportation Noise, 1980
Outdoor Sound Level in Leq [dB(A)]
>55 dB(A)
Annoyance
>60 dB(A)
Normal
Speech Level
>65dB(A)
Communication
Interference
>70dB(A)
Muscle/Gland
Reaction
>75 dB(A)
Changed Motor
Coordination
37.0% 18.0% 7.0% 2.0% 0.4%
Source: OECD, 1993.
* Noise levels are site specific and dissipate with increasing distance from the source; as a
result, an aggregate national noise emissions figure is not meaningful.
* Typical noise levels at 100 feet are 50 dB(A) for light auto traffic; 70 dB(A) for freeway
traffic, and 90 dB(A) for city traffic (BTS, 1994).
* Typical noise emissions per vehicle are 85 dB(A) for an auto, 95 dB(A) for a heavy truck,
100 dB(A) for a bus, and 110 dB(A) for a motorcycle (BTS, 1994).
QwmFisQ ACTIVITY INDICATORS
4 Refer to Appendix A for data on vehicle travel.
OfHS? QtWOTJREo DATA AND LOCAL EXAMPLES
* An FHWA survey estimated that more than 929 miles of noise barriers had been constructed
as of 199247 (FHWA, 1994b).
4 Between 1980 and 1992 there were an average of 57 miles of new noise barriers built per
year (FHWA, 1994b). Note that there are almost 13,000 miles of urban interstate and almost
150,000 miles of other urban arterials (FHWA, 1993).
* Effective noise barriers can lower noise levels by 10-15 decibels (dB), which reduces traffic
noise by as much as one half in many cases. (FHWA, 1992b)
DESCRIPTION OF IMPACT
Noise associated with road transport comes from engine operations, pavement-wheel contact,
aerodynamic effects, and vibrating structures during operations. Heavy trucks and buses cause more
California did not provide data for the years 1990,1991, and 1992.
76
-------
The Indicators: Highway
noise per vehicle than cars. The issue of noise is generally discussed in terms of the number or
proportion of people affected. The findings of numerous research projects in OECD countries on the
effects of noise and its wider repercussions indicate that an outdoor sound level of 65 dB(A) is
"unacceptable," and an outdoor level of less than 55 dB(A) is desirable (OECD, 1993). Noise is
thought to cause stress and other health problems and lower property values. It can also affects local
habitats of species near roads.
CAUSAL FACTORS
4 Level of road activity; traffic volumes
4 'Speed of traffic
4 Proportion of heavy vehicles (one truck emits the equivalent noise of 28 to 60 cars)
' 4 Population density near road.
4 Existence and effectiveness of noise barriers
4 Effectiveness of devices such as mufflers and quiet vehicles «
HAZARDOUS MATERIALS INCIDENTS DURING TRANSPORT
PRESENTATION OF INDICATORS
QUANTIFIED OUTCOME/RESULTS INDICATORS .
4 No statistics were found regarding the number of species or acres nationwide affected by
commodity spills or other hazardous materials incidents.
QUANTIFIED OUTPUT INDICATORS '•-.'- • i
4 An average of 646,000 gallons of hazardous materials were reported spilled annually on
highways from 1990 to 1994, more than three fourths of which was flammable and/or
combustible liquid (U.S. DOT, RSPA, HMIS database) (see tables and graphics).
4 - Almost 10,000 hazardous materials releases were reported annually from 1990 to 1994 (U.S.
DOT, RSPA, HMIS database) (see tables and graphics).
Distribution of Gallons of Hazardous Materials
Spilled in Highway Transport, 1990-1994
All Other
14%
. Flammable -
Corrosive Material • /\ ? 1A Combustible
11% / \ |K~ \ Liquid
55%
Combustible
Liquid
20%
, Source: U.S. DOT, RSPA, HMIS
77
-------
Indicators of the Environmental Impacts of Transportation
Hazardous Material Highway Incidents, Annual Average, 1990-1994'
48
Class
Flammable - Combustible Liquid
Corrosive Material
Poisonous Materials
Combustible Liquid
Miscellaneous HAZMAT
Oxkfizar
Nonflammable Compressed Gas
Flammable Gas
Organic Peroxide
Flammable Solid
Other Regulated Material, Class A
Other Regulated Material, Class E
Poisonous Gas
Very Insensitive Explosive
Flammable Solid (per-1991)
Radioactive Material
Dangerous when Wet Material
Spontaneously Combustible
Other Regulated Material, Class B
Other Regulated Material, Class C
Explosive No Blast Hazard
Explosive Mass Explosion Hazard
Explosive Fire Hazard
Explosives, Class A
Other Regulated Material, Class D
Explosives, Class C
Irritating Material
Infectious Substance (Etiologic)
Explosive Protection Hazard
Total
Number of
Incidents
3,984.0
3,477.2
594.6
552.0
289.2
226.8
138.0
74.4
72.8
42.4
37.8
25.8
21.8
10.8
9.2
9.0
8.2
7.0
3.8
3.6
1.2
1.0
0.8,
0.8
0.6
0.6
0.6
0.4
0.2
9,594.6
Gallons
Released
358,341.2
71,726.4
5,622.0
132,395.2
26,781.0
5,453.1
28,064.7
10,573.9
135.9
1,048.9
655.5
586.3
265.0
653.1
7.0
2,000.9
2.2
3.6
164.6
1,883.0
0.0
40.3
0.2
2.4
0.1
646,406.3
Pounds Cubic Feet mCi Clean-up Cost
Released Released Released and Loss of
Material
1123.3
11,010.2
9,764.6 15.4
121,406.7
69,305.2
111.7 342,646.0
32,370.3
502.7
1,054.2
. 15.9
42,812.3
400.2 219.0
17,867.4
4,042.7
. 308.0
705.4
145.5
220.5
5,017.7
163.4
5.3
0.2
2,584.4
0.4
0.4
0.2
288,568.6 375,250.6
13,571,050
3,266,310
1,237,813
3,029,450
626,084
293,549
424,636
594,446
61,467
101,809
43,397
110,859
43,093
56,423
13,251
18.9 31,982
1 1 ,297
10,377
9,858
36,949
104,263
24,764
3
27,486
55
64
1,39
185
24
18.9 23,731,081
Source: U.S. DOT. RSPA, HMIS.
* Materials release rates associated with transporting hazardous materials by truck appear to be
as large as potential releases at .treatment and disposal sites (U.S. EPA, 1984).
* The quantity of hazardous materials remaining in the environment after cleanup efforts is
unknown.
QtMffflFiB) ACTIVITY INDICATORS
* Trucks carry over 60 percent of the hazardous materials transported in the U.S. (Atkinson,
1992).
1 U.S. DOT, RSPA, HMIS Database.
78
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The Indicators: Highway
OTHER QUANTIFIED DATA AND LOCAL EXAMPLES
4 Of the 7,585 hazardous materials highway incidents reportecl to HMIS in 1991, 79 percent
were a result of human error, 15 percent from packaging failure, 3 percent from vehicle
accidents, and 3 percent from other causes (U.S. DOT, RSPA, 1991).
4 Approximately 99 percent of the fatalities and injuries in accidents involving hazardous
materials trucks resulting from physical collision were not related to the hazardous materials
release (Harwood et al., 1990).
DESCRIPTION OF IMPACT . -
'
The potential for commodity releases during highway transportation is important to consider because
of the large and growing role truck transport plays in domestic freight movement. In 1993, track
transport accounted for 35 percent of the ton-miles and 53 percent of the tonnage moved during
d9mestic intercity transport, excluding pipelines (Eno, 1994). In particular, commodity spills of
hazardous materials may impose substantial costs for product loss, carrier damage, property damage,
evacuations, and response personnel and equipment. The Hazardous Materials Information System
(HMIS) database, maintained by U.S. DOT/RSPA, contains a record of all reported hazardous
materials incidents occurring during truck transport (except for intrastate only operators), including
type of material spilled, number of injuries/fatalities, and estimated clean up costs.
The number of hazardous material incidents is not necessarily indicative of the environmental impact
of such incidents, since it may be possible to clean up most of the materials released. If not properly
contained, however, hazardous materials incidents may cause environmental damage such as air and
water pollutions damage to fish and wildlife, and habitat destruction. The environmental impact of any
given hazardous materials spill is highly site-specific. It depends on the type and quantity of material
spilled, amount recovered in cleanup,, chemical properties (such as toxicity and combustibility), and
im'pact area characteristics (such as climatic conditions, flora and fauna density, and local
topography). It should be noted that while the overall impact of incidents may be small for the nation
as a whole, any hazardous material spill may have severe impacts on flora and fauna in the location of
occurrence. . ,
CAUSAL FACTORS '
4 Quantity of hazardous materials transported and distance transported
* Accident or spill rate
4 -Type (toxicity/hazard) and quantity of materials spilled
4 Effectiveness of cleanup efforts ,
4 Population density
4 Sensitivity of local habitats/species
ROADKILL ,
PRESENTATION OF INDICATORS _'•.-.
QUANTIFIED OUTCOME/RESULTS INDICATORS
4 In the United States, roadkill losses are estimated to be at least 1 million animals per day due
to conflict with traffic while crossing roads (Tolley, 1995).
79
-------
Indicators of the Environmental Impacts of Transportation
4 When a new road is built, roadkill is estimated to increase by at least 200 percent (Aaberg et
al., 1978; Green and Reilly, 1974).
C^mm) OUTPUT INDICATORS
4 An output indicator for roadkill is not meaningful since the immediate impact—killed
animals—is an outcome. There are no emissions or indirect means to measure environmental
harm.
QUAttmsoAcmtY INDICATORS . "
4 Refer to Appendix A for data on vehicle travel.
OTHSiQUANmSDDATAANOLOCALEXAMPLES
4 In 1981, deer-related accidents constituted 7 percent of police-reported accidents in
Michigan and resulted in direct costs exceeding $17 million (Hansen and Wolfe, 1983).
DESCRIPTION OF IMPACT
Roads passing through wildlife habitat are a threat to various kinds of wildlife, especially in the first
several years after a new road is constructed. It may take several years for wildlife to adapt to
changes such as a new roadway in their habitat. Roadkill incidents in the initial few years of a road
are at least double the rate of incidents observed over the long term.
Most studies and statistics on roadkill focus on deer, elk, antelope, moose and similar large wilderness
animals. However, several studies of specific roadway corridors have documented incidents relating
to a broader range of creatures (Foster and Humphrey, 1992). Although few national composite
figures are available, many states track the number of animal-related incidents on their major
roadways.
VMT likely has some relationship to wildlife strikes, but the exact nature of that relationship is
unclear. In the case of a new road, the introduction of "new" VMT into a region generally results in
increased strikes. Once the habitat adapts to the presence of the road, however, the impact of
increased VMT is less clear. Road mileage may have a significant impact on wildlife, strikes, and may
be a more important factor than VMT. The size of the animal population in a given area is also a
primary determinant of roadkills.
There is little consensus regarding the most effective means of preventing roadkill incidents. Wildlife
often manages to circumvent protective fencing by jumping over, going around, or going through
open gates and holes. Reflectors, lighting, underpasses dedicated to wildlife, mirrors and signage
have been shown by some studies to be relatively ineffective at changing the behavior of both drivers
and wildlife (Fomwalt et al., 1980; Colorado Division of Wildlife, 1980; California Department of
Transportation, 1980; Lehtimaki, 1981).
CAUSAL FACTORS
4 Habitat fragmentation, barriers to crossing formed by roads
4 Lack of driver education on wildlife hazards and alertness
4 Gaps in barriers and fences due to human activities
4 Distance between edge of road and forest/vegetation
SO
-------
The Indicators: Highway
Visibility (alignment, lighting, etc.)
Location of road relative to wildlife habitat (urban/rural)
81
-------
-------
The Indicators: Highway
4. MOTOR VEHICLE MAINTENANCE AND SUPPORT
Besides vehicles and streets, road transport requires support facilities such as motor freight terminals,
bus yards, fuel storage tanks, and auto fueling and service stations. These are discussed below.
Releases during
, Terminal Operations:
'Tank Truck Cleaning,
Releases durin
Passenger Vehicl
Cleaning,
Maintenance,
Repair, and
Refueling
Leaking Underground
Storage Tanks
RELEASES DURING TERMINAL OPERATIONS: TANK TRUCK CLEANING, MAINTENANCE, REPAIR, AND
REFUELING
PRESENTATION OF INDICATORS .
QUANTIFIED OUTCOME/RESULTS INDICATORS •
4 Data on water quality impacts to streams, rivers, and lakes, and related habitat due to tank
truck terminal .operations are not available. Data on health effects from air pollution coming
from terminals are also not available.
QUANTIFIED OUTPUT INDICATORS
4 Tank car and rail car cleaning operations emit 1.25 million pounds of VOCs per year (U.S.
s EPA Source Assessment Study of 1978 as cited in U.S. EPA, 1995a).
* Data on other wastes generated from motor freight terminal operations have not been
estimated at the national level (see table for list of wastes generated).
83
-------
Indicators of the Environmental Impacts of Transportation
Typical Motor Freight Terminal Operations:
Materials Used and Types of Waste Possibly Generated
Process/Operation
Materials Used
Types of Waste Generated
Unloading or
Cleaning of Tank
Cars
Rust Removal
Painting
Paint Removal
Exterior Washing
Equipment degreasing
Refueling
Changing of batteries
Solvents, alkaline
cleaners
Naval jelly, strong acids,
strong alkalis
Enamels, lacquers,
epoxies, alkyds, acrylics,
primers, solvents
Solvents, paint thinners,
enamel, white .spirits
Solvents, cleaning
solutions
Degreasers, engine
cleaners, acids, alkalis,
cleaning fluids
Gasoline, diesel fuel
Lead-acid batteries
Acid/alkaline wastes
Toxic wastes
Solvent wastes
Residual tank contents
Acid/alkaline wastes
Ignitable wastes
Toxic wastes
Paint wastes
Solvent wastes
Paint'wastes
Toxic wastes
Solvent wastes
Solvent wastes
Oil and grease
Ignitable waste
Combustible solids
Acid/alkaline wastes
Evaporative losses - VOCs
Fuel drips and spills
Acid/alkaline wastes
Batteries (lead acid) '
Source: U.S. EPA/RCRA Fact Sheet: Motor Freight/Railroad Terminal Operations, 1993; U.S. EPA, 1995a.
* There are 1,841 truck/land tank cleaning facilities in the U.S. (EPA Office of Water as cited
in U.S. EPA, 1995a).so
* Approximately 90 percent of transportation equipment cleaning facilities discharge
wastewater to publicly owned treatment works or combined treatment works (privately .
owned by multiple facilities) after some amount of treatment. Some facilities discharge
directly to surface waters under the National Pollution Discharge Elimination System
(NPDES) permits or to underground injection wells under Safe Drinking Water Act permits
(U.S. EPA, 1995a). Allowable emissions could be tracked based on these permits, although
actual emissions may vary.
DESCRIPTION OF IMPACT
Terminal operations include short- and long-haul truck activities (such as tank car unloading and
cleaning), furnishing of terminal facilities for passenger or freight traffic, and cleaning and
50 Land facilities are those that clean any combination of the following equipment: tank trucks, rail tank cars,
intermediate bulk carriers, intermodal tank containers.
S1 National Pollutant Discharge Elimination System
84
-------
The Indicators: Highway
maintenance functions including equipment degreasing, exterior washing, and painting. Many of these
processes use materials that are hazardous or may in turn generate hazardous waste or wastewater. In
addition, refueling operations impact the environment through spills and drips of fuel, and through
fuel tank vapors that are displaced when the tank is filled with liquid fuel. The actual impact of
terminal activities on the environment depends in a large part on the type and volume of operations,
, level of cleanliness required, type of waste generated, and efficacy of wastewater treatment systems in
place.
A significant source of pollution is the cleaning of tank truck interiors. The typical tank truck car has
a volume of 3,500-8,000 gallons and generates about 500-1,000 gallons of wastewater during
cleaning, resulting in the output of spent cleaning fluids, fugitive VOC emissions, water treatment
system sludges, and tank residues. The disposal and treatment of tank heels can also be source of
pollution for tank cleaning facilities. The typical heel volume of a tank truck car is 5-10 gallons per
tank, and a facility's wastewater treatment system may be adversely affected by, or may not
adequately treat, a slug of concentrated tank residue. Incompatible heels are usually segregated and
resold to a reclaimer or shipped off-site for disposal. Heels that are composed of detergents, solvents,
acids, or alkalis can be stored on-site and used as a tank cleaning fluid or to neutralize other tank heels
(U.S. EPA, 1995a).
Relatively small amounts waste and wastewater are generated from the washing, maintenance., and
painting of motor vehicle exteriors. Typical hazardous wastes generated include spent solvents, spent .
caustics, strippers, paint chips, and paint sludges. Wastewater is generally treated on-site and then
discharged to a public treatment works.
The primary source of toxic chemicals released during terminal operations are substances dissolved or
suspended in wastewater, primarily during cleaning of tank interiors. Other potential environmental
impacts of terminal operations include air emissions and residual wastes. Fugitive emissions of VOCs
arise from tank heels and residues, cleaning solutions, painting and paint stripping, and refueling
vapors. Residual wastes are generated as sludges from wastewater treatment systems, residues
removed from the inside of tanks, and hazardous wastes" from painting, paint removal, and cleanin<* of
parts (U.S. EPA, 1995a).
CAUSAL FACTORS ; ' '
•f Number of terminals
* Type and level of terminal operations
* Materials used during terminal operations
* Wastewater treatment capabilities
RELEASES DURING PASSENGER VEHICLE CLEANING, MAINTENANCE, REPAIR, AND REFUELING
PRESENTATION OF INDICATORS
QUANTIFIED OUTCOME/RESULTS INDICATORS
* Data on water quality impacts on streams, rivers, and lakes, and related habitat due to gas
and service station operations are not available. Data on health and habitat effects from air
pollution related to gas and service stations are also not available.
85
-------
Indicators of the Environmental Impacts of Transportation
QtMNDRG) OUTPUT INDICATORS
* National statistics are not readily available, although EPA's MOBILE model produces
emissions factors for hydrocarbons due to refueling on a per mile basis.
QUWTJBEO ACTIVITY INDICATORS
* 75 percent of transit agencies surveyed collect and treat wastewater from bus washing
operations.52 (TCRP, 1995a)
* 65 percent of transit agencies wash their active bus fleets daily during summer months; 81
percent wash daily during the whiter.53 (TCRP, 1995a)
DESCRIPTION OF IMPACT
Facilities such as gas stations, maintenance shops, and service stations impact the environment
through runoff of gas, oil, and dirt; waste releases to sewer systems; air emissions; and waste disposal.
Research has found that areas where motor vehicles are serviced, fueled, or parked may have higher
loadings of pollutants in road runoff.
Fueling activities generate air emissions due to VOC losses during transfer. There are two types of
refueling losses: Stage 1 losses associated with the refilling of underground storage tanks, and Stage 2
losses occurring during the transfer of fuel from pump to automobile gas tank. Both Stage 1 and Stage
2 losses are counted as stationary source emissions by EPA's Office of Air Quality Planning and
Standards. These are not included in this report because they are not reported separately.
CAUSAL FACTORS
* Number of maintenance facilities
* Type and level of maintenance operations
* Materials used during maintenance operations
* Wastewater treatment capabilities
LEAKING UNDERGROUND STORAGE TANKS (USTs) CONTAINING FUEL
PRESENTATION OF INDICATORS
OUTCOME/RESULTS INDICATORS
In 1992, 50 states and U.S. territories reported leaking USTs to be a significant source of
ground water contamination. Above ground storage tanks were reported as a problem by 12
states (U.S. EPA, 1994b).
52 Based on survey of TCRP survey (1995) of 120 geographically diverse transit agencies in the U.S. and
Canada; 52 respondents.
53 Based on survey of TCRP survey (1995) of 120 geographically diverse transit agencies in the U.S. and
Canada; 52 respondents.
86
-------
The Indicators: Highway
QUANTIFIED OUTPUT INDICATORS . .
4 34,000 confirmed annual releases from underground storage tanks (USTs) occurred in 1994,
a 50 percent reduction from the 68,000 releases in 1990 (U.S. EPA as cited in Industrial
Economics, 1995). A majority of these tanks likely are associated with transportation.
4 Quantities emitted are unknown.
Total Releases from Underground Storage Tanks
CO
60 -
CO
£ I40
o o
0
68,000
34,000
1990
1994
QUANTIFIED ACTIVITY, INDICATORS
4 There were 1.6 million active petroleum USTs in 1995, an 11 percent decrease from the
estimated 1.8 million tanks in 1991 (U.S. EPA, as cited in Industrial Economics, 1995).
4 More than 20 percent of existing USTs are installed partially or completely below the water
table (U.S. EPA, as cited in Industrial Economics, 1995). .
* Over 170,000 USTs are closed annually, resulting in the elimination of many older, bare-
• steel tanks (U.S. EPA, as cited in Industrial Economics, 1995).
* Some 232,835 leaking UST cleanups have been initiated since 1988; 126,608 of these
cleanups have been completed (U.S. EPA, as cited in Industrial Economics, 1995).
4- Over 1,000 emergency responses to.tank situations relating to potential environmental
releases are conducted by federal and state UST officials each year (U.S. EPA, as cited in •
Industrial Economics, 1995).
4 Highway/road transport accounts for 76 percent of all transportation-related petroleum
consumption (U.S. DOE, 1994a),
DESCRIPTION OF IMPACT . ' , ' • .- '
Although USTs may contain various hazardous substances or other regulated materials, the vast
majority store petroleum and are commonly discussed in the context of transportation, particularly
highway transportation. EPA estimates that there are approximately T.6 million petroleum USTs and
an additional 37,000 tanks containing hazardous substances (U.S. EPA, as cited in Industrial
Economics, 1995). At the same time, 96.6 percent of all transportation sector operations in the U.S.
use petroleum for fuel. Highway/road transport accounts for-76 percent of all transportation-related
petroleum consumption (U.S. DOE, 1994a).
Leaking USTs can be a major source of groundwater contamination. Releases from tanks and piping
occur from corrosion of older, unprotected steel tanks and piping, or from cracks in tanks made from
87
-------
Indicators of the Environmental Impacts of Transportation
other materials. Overfilling and spillage during refueling are also responsible for significant numbers
of accidental releases. More stringent regulation of USTs (design, citing, installation, monitoring) is
resulting in a decrease in the total number of active USTs and the volume of contaminants released.
The 1986 amendments to the Resource Conservation and Recovery Act (RCRA) established a $500
million Leaking Underground Storage Tank Trust Fund, financed through a tax on gasoline, to
cleanup leaking UST sites. In 1998, all existing USTs will require spill protection through catchment
basins, automatic shutoff devices, overfill alarms, and mandatory corrosion protection for steel tanks
and piping.
CAUSAL FACTORS
* Number of leaking underground storage tanks (USTs)
* Type and quantity of materials released from leaking USTs
* Spill protection mechanisms
* Cleanup efforts initiated and completed
* Location of groundwater table
4 Sensitivity of local ecosystems
4 Treatment of drinking water
SS
-------
The Indicators: Highway
5. DISPOSAL OF VEHICLES AND PARTS
Tire Disposal
Vehicle Scrapage
Lead-acid Battery
Disposal
Motor Oil Disposal
Potential Water, Soil, or
Air Contamination
SCRAPPAGE OF VEHICLES
PRESENTATION OF INDICATORS
QuAffriFiED OUTCOME/RESULTS INDICATORS
* Estimates are not available on the health and environmental impacts of landfilling or
other disposal of"scrapped vehicles.
QUANTIFIED OUTPUT INDICATORS
^
4 National data on emissions from the disposal of vehicles are not^ available.
QUANTIFIED ACTIVITY INDICATORS
4 Approximately 9 million automobiles (about 94 percent of all scrapped vehicles) are
collected and recycled annually at one of the 12,000 scrappage/disassembly locations in
the U.S. (U.S. EPA, 1995b).
* At least 75 percent of the material collected from scrapped vehicles is recycled for raw-
material use, and 25 percent landfilled. This comprises about 1.5 percent of total
municipal landfill waste (U.S. EPA, 1995b).
89
-------
Indicators of the Environmental Impacts of Transportation
Composition of
Vehicle Material Waste Municipal Landfill Material
-«•„ -, Autos
Landfilled
Other
Recycled Landfill Waste
OTHER QUANTIFIED DATA AND LOCAL EXAMPLES
* Data on tonnages of these items were not readily available, but about 21 percent of a
vehicle's weight (total is approx. 3000 pounds) is non-metals (of which, 38 percent is
plastic, 12 percent fluids, 21 percent rubber, 14 percent glass, and 16 percent other)
(U.S. EPA, 1995b).
DESCRIPTION OF IMPACT
When a vehicle is dismantled, fluids can be recovered, including oil, antifreeze, and refrigerant.
Solid parts such as the radiator and catalytic converter are removed for recycling or reuse. The
battery, fuel tank, and tires are also separated. The remaining vehicle is shredded (at one of the
200 shredding operations in North America) and sorted into ferrous, nonferrous (8.7 percent of
the whole vehicle), and residual components. The residue contains plastics, glass, textiles, metal
fines, and dirt, which are generally all landfilled.
CAUSAL FACTORS
* Number of vehicles scrapped
* Fraction disposed of properly (through recycling, recovery, etc.)
4 Use of hazardous materials in vehicles
* Recovery rate of materials in scrapped vehicles
MOTOR OIL DISPOSAL
PRESENTATION OF INDICATORS
Qt*WnF!ED OUTCOME/RESULTS INDICATORS
•* Statistics are not available on amount of groundwater contamination or'other
environmental outcomes specifically attributable to motor oil disposal.
Qwaweo OUTPUT INDICATORS
* No data are available on the amount of motor oil that is released to land or water.
90
-------
The Indicators: Highway
QUANTIFIED ACTIVITY INDICATORS
+ 161 million gallons (23 percent) of the 714 million gallons of used motor oil collected
annually are improperly disposed (U.S. EPA, 1994c).
23% of used oil is
improperly disposed
DESCRIPTION OF IMPACT
Disposal of used motor oil can pollute sewers, wastewater treatment plants, and groundwater
supplies. Used motor oil contains toxicants such as lead and benzene and, if improperly disposed
of, can be a significant source of water pollution. The oil from just one oil change is enough to
significantly contaminate a million gallons of fresh water.
CAUSAL FACTORS
* Quantity of oil used in motor vehicle operations.
* Recovery rate
* Groundwater contamination and seepage-prevention measures at the disposal site
V Sensitivity of local ecosystems
* Water treatment technologies
TIRE DISPOSAL
PRESENTATION OF INDICATORS
QUANTIFIED OUTCOME/RESULTS INDICATORS '
* Statistics are not available, on amount of groundwater contamination, air pollution, or
other environmental outcomes specifically attributable to disposal of tires from motor
vehicles. .
QUANTIFIED OUTPUT INDICATORS . '
4 Waste tire incineration was responsible for approximately 2 pounds of polychlorinated
biphenyl (PCB) emissions out of total national emissions of 282 pounds in 1990. Since
1990, the rate of tire incineration has increased dramatically (U.S. EPA, 1995e).
QUANTIFIED ACTIVITY INDICATORS
+ In 1995, 252 million scrap tires were generated, with 69 percent recovered (174.5
million). 74.4 percent of those recovered were burned as tire-derived fuel (Scrap Tire
Management Council)
91
-------
Indicators of the Environmental Impacts of Transportation
In the early 1990s, by contrast, 242 million tires were scrapped annually, with only a 30
percent recovery rate, leaving 169 million tires to be landfilled or stockpiled each year
(U.S. EPA, 1993b).
In 1990,1.6 million tons of rubber tires were discarded into the municipal waste stream,
accounting for 1.0 percent of municipal waste stream (U.S. EPA, 1992).
Approximately 800 million tires remain in stockpiles in the U.S. (Hilts, 1996).
TIRE DISPOSAL
Landfilled
Recovered
Recycled
174.5M
69%
Burned for
„„ Fuel
74%
300
Scrap Tire Generation in the United States
Tires Consumed by Reuse Markets
250 -
200 -
150 -
100
I — I
—
—
IUU70
•o
1 80%
a:
jg 60%
15 40%
| 20%
o
°- no,
11%
1 -:.'•-'.(
1 "I
70%
1984 1985 1986 1987 1988 1989 1990 199° 1995
Source:US EPA, Markets tor Scrap Tires, 1 991 . Source:Hilts, 1 996.
DESCRIPTION OF IMPACT
Disposal of used tires from motor vehicles can pollute sewers, wastewater treatment plants, and
groundwater supplies, as well as take up landfill capacity. Many landfills do not allow tire
disposal because tires decompose extremely slowly; they collect gases released by decomposing
garbage, and then gradually float up to the surface of the landfill. In addition, used tires contain
oil, making them a fire hazard, and may retain stagnant water, an ideal breeding ground for
mosquitoes.
Tires pose a considerable fire hazard because once ignited, they can emit toxic gases, such as
polyaromatic hydrocarbons, CO, SO2, NO2, and HC1 (U.S. EPA, October 1991). The use of water
to extinguish tire fires can result in soil and water contamination from oils generated by the
burning tires. Furthermore, these fires can be extremely difficult to extinguish. Stockpiles of
tires have been known to bum continuously for more than a year (U.S. EPA, October 1991).
92
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The Indicators: Highway
CAUSAL FACTORS i
4 Quantity of tires disposed (based on number of vehicles and tire service life)
* Recovery rate
4 Method of disposal or recycling
* Proximity to human population or habitat
4 Toxic constituents in tires
LEAD-ACID BATTERIES DISPOSAL
PRESENTATION OF INDICATORS
QUANTIFIED OUTCOME/RESULTS INDICATORS
4 Statistics are not available on amount of groundwater contamination or other
environmental outcomes specifically attributable to disposal of batteries. • '
QUANTIFIED OUTPUT INDICATORS • . -
4 No data are readily available on discharge of toxics from the disposal of lead-acid
batteries.
QUANTIFIED ACTIVITY INDICATORS - '
4 In 1990, 1.7 million tons of spent lead-acid batteries were generated in the municipal
. • waste stream, but 96.6 percent of these were recovered and recycled nationwide, leaving
only 100,000 tons to be discarded (U.S. EPA, 1992).
4 In 1990, 100,000 tons of spent lead-acid batteries were discarded into the municipal
waste stream, which is less than 0.05 percent of the total municipal waste stream (U.S.
EPA, 1992).
4 According to the U.S. Bureau of Mines, about 79 percent of lead consumed in 1989 was
used in lead-acid batteries. Close to three fourths (by weight), or 0.75 million metric
tons, of the lead-acid batteries shipped domestically in 1989 were automotive batteries
(U.S. EPA, January 1992). • '
4 The 1985 battery recycling rate was estimated to be 69.5 percent in a report prepared for
EPA in 1987. The report also found that battery recycling rates fluctuated widely over
the period 1960 to 1985, with recycling rates having a strong correlation to the price of .
lead (U.S. EPA, January 1992).
4 A 1991 study by the Battery Council International (BCI), a battery manufacturers' trade
association, estimated that the lead-acid battery recycling rate (excluding "consumer"
batteries) is roughly 95 percent. A study by the Oregon Department of Environmental
Quality estimated that the state of Oregon's lead-acid battery recycling rate was between
90 and 99.9 percent for 1990 (U.S. EPA, January 1992).
. DESCRIPTION OF IMPACT . • . .
Disposal of used parts and fluids from vehicles and batteries can pollute sewers, waste water
treatment plants, and groundwater supplies, as well as take up landfill capacity. The typical car
battery weighs 30-36 pounds and contains 18-20 pounds of lead acid and electrolyte solution.
Lead-acid batteries, primarilyfrom automobiles, rank first, by a wide margin, of the products
containing lead that enter the waste stream.. The disposal (versus recycling) of such batteries
93
-------
Indicators of the Environmental Impacts of Transportation
means the introduction of lead, sulfuric acid, and polypropylene, all hazardous waste, into
landfills or the environment.
An accurate battery recycling rate is difficult to establish due to a number of factors, including
fluctuations in annual battery sales, time lags in data due to various batteries' life spans, and
imports and exports of batteries and scrap lead. Still, information from several sources suggests
that the recycling rate for lead-acid batteries is increasing (U.S. EPA, January 1992). Recycling
of batteries to recover lead has a significant influence on the amount of lead discarded. A
number of states have made a strong commitment to recycling.
CAUSAL FACTORS
4 Quantity of batteries used in motor vehicle operations
* Recovery rate
4 Groundwater contamination and seepage prevention measures at the disposal site
4 Proximity to human population or habitat
94
-------
The Indicators: Rail
EjJU.fc ENVIRONMENTAL* INDICATOR'S
This section presents the quantitative indicators available for tracking the nationwide environmental
impacts of rail transportation. Rail is defined broadly to encompass freight transportation, as well as
intercity (Amtrak) and intracity passenger rail. Intracity passenger rail includes heavy rail (subways
and elevated systems), light rail, and commuter rail. In some cases, data for all these forms of
transportation were not available, so rail indicators may provide partial data (for example, transit
impacts may be excluded in some categories). For each of the five basic categories of activities
affecting the environment, the various impacts are listed.
HOW EACH IMPACT IS PRESENTED IN THIS SECTION
Each environmental impact is covered in one or more pages of text and graphics, with the following
key subsections: '
4 Presentation of indicators
The key indicators that have been quantified are presented. Outcome
indicators are listed first since they provide information on end results and
are theoretically the most desirable type of indicator. Unfortunately, actual
quantified data are often unavailable or of poor quality. In many instances,
the only available data on outcomes are the number of states reporting a
problem. This information is often incomplete (not all states may examine the
problem), vague (states may define the problem differently), or only
somewhat relevant (the contribution of transportation to the problem may be
unknown). As a result, output indicators—such as emissions data—are
presented. These statistics may be an easier and more valid measure.for
policy makers to examine and track over time. Finally, activity indicators
(defined broadly to include infrastructure, travel, and other activities) are
listed when they are the best available indicators or when outcome and output
indicators are not adequate.
To avoid repetition within the report, basic infrastructure and travel
indicators are listed in Appendix A for each mode of transportation. .
Appendix B contains additional relevant statistics on monetized values of
health and other impacts; these outcome indicators are listed separately since
there is generally more uncertainty regarding these figures.
• Description of impact
The nature of the impact is briefly defined and explained here.. More
complete descriptions of these impacts are available in reference works listed
in the bibliography. ,
95
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Indicators of the Environmental Impacts of Transportation
• Causal factors: Variables that change over time and between locations
Policy makers find it very useful to understand the driving forces behind
environmental impacts. Understanding the key causal factors is critical to
explaining observed trends in indicators. They also help in estimating how
local impacts may differ from national averages. These causal variables, then,
explain how the impacts differ over time and geographic location. Most
importantly, they suggest potential policy levers. Policies can be designed to
focus on any of the key variables (e.g., grams emitted per mile) that
determine the magnitude of an environmental impact.
The following table provides an overview of the available indicators for each impact. It is important to
note two points about what is included in this table: First, indicators are listed only where they have
been quantified at the national level; if an impact has not been-quantified, no "potential" indicator is
listed here. For each specific activity and its impact, the table provides a summary of the availability
of quantitative data for indicators of outcomes, output, and activity. Second, the table shows only the
best indicator for each impact rather than listing various alternative types of indicators for a given ,
impact. The exceptions to this are when multiple indicators are needed to address all aspects of an
issue or where some indicators are otherwise insufficient. Although outcome indicators are
theoretically the most desirable type of indicator, actual quantified outcome data are often unavailable
or of poor quality. As a result, output indicators—such as emissions levels—tend to be the most
reliable and valid measures available hi most cases. Activity indicators are presented in this table
when they are the best available indicators or when outcome and output indicators are not adequate.
96
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-------
The Indicators: Rail
1. RAILWAY CONSTRUCTION, MAINTENANCE, AND ABANDONMENT
Although rail construction was once significant, new construction is extremely limited in comparison
to historical levels. Purposes for new construction include more efficient operations, competitive
service, better access to industrial facilities, and high-speed passenger service. The only recent
growth in rail transportation infrastructure of significance is transit rail. In practice, abandonment of
rail lines and facilities is more of an issue than new construction. Although the short line and
regional railroad industry continues to grow, accounting for nearly 25 percent of the nation's
174,000-mile railroad system, currently most new short line and regional railroads have been created
from marginal lines purchased from Class I railroads that would otherwise have abandoned them
(ICC, 1993). Until recently, in the U.S., the Interstate Commerce Commission (ICC) has authorized
and monitored interstate railway track construction and abandonment and played a role in
environmental impact assessment.
In addition to long-term land take in the right of way, railway construction or salvage activities may
have temporary, but'significant, environmental impacts due to drilling and excavation activities,
disposal of excess material, and discovery of hazardous material in the right-of-way.
Air Pollutant Emissions during
Construction/maintenance
Habitat Disruption
HABITAT DISRUPTION AND LAND TAKE
PRESENTATION OF INDICATORS
f - *' - .
QUANTIFIED OUTCOME/RESULTS INDICATORS , ••.'••
* The number of species or acres of sensitive habitat adversely affected by rail construction
and/or abandonment is not known. Since construction and abandonment cases have been
99
-------
Indicators of the Environmental Impacts of Transportation
subject to environmental review by the ICC, the impacts of such activities presumably have
been considered and minimized.
QUANTIFIED OUTPUT tecaTtws
* In 1993, 1 .3 square miles of land were taken for new construction of intercity track, and
land area used for intercity rail transport grew by about 0.05 percent (Apogee estimate based
on ICC, 1993; Carpenter, 1994).
4 Railway track and buffers occupy about 4 percent of the surface area in large cities (Tolley,
1995).
* Existing intercity (freight) rail covers an estimated 2,784 square miles of land in the U.S.,
occupying less than 0.1 percent of total land area (ICC, 1993; Carpenter, 1994).
4 In 1993, 82 new miles of intercity track were constructed (ICC, 1993).
4 In 1993, 441, 381 tons of new rail were laid (AAR, 1993).
4 As of January 1995, 170 miles of commuter rail, 71 miles of heavy rail, and 83 miles of
light rail were under construction in the U.S. (APTA, 1995).
4 Existing rail mileage is 177,000 miles of track, of which 168,964 miles are owned and
operated by freight railroads; Amtrak operates a majority of its system on track owned by
freight companies (AAR, 1993). Miles of track owned by Class I railroads has been
decreasing due to sale of track to non-Class I railroads and some abandonment.
Miles of Track Owned
Class I Railroads
400,000
350,000
300,000
| 250,000
O 200,000 •
:i 150,000
E
100,000
50,000
1920
1940
1960
1980
2000
Source: AAR, 1994.
Passenger rail stations include 540 stations served by Amtrak (Amtrak, 1994), 911 heavy
rail transit stations (U.S. DOT, 1994), and 958 commuter rail stations (U.S. DOT, 1994).54
The ICC authorized over 1,897 miles of track abandonment in Fiscal Year 1993, and 1,824
miles the previous year. Environmental review was conducted for over 130 abandonment
cases in Fiscal Year 1993, and in 60 cases the ICC imposed limitations on salvage activities
to prevent wildlife disturbance or other environmental impacts (ICC, 1993).
54 Figures for Amtrak stations are from 1994, heavy rail and commuter rail stations from 1990.
100
-------
The Indicators: Rail
DESCRIPTION OF IMPACT ' •
Since the addition of new railway infrastructure involves land take in the right-of-way and
fragmentation of habitat, both flora and fauna in wetlands and terrestrial habitats are affected. The
average width of land occupied by a railway track and buffer zone is about 0.016 miles (25 meters)
(Carpenter, 1994). Rail transport thus requires about 0.016 square miles of land space per mile of
railway track and surrounding buffer; as a result, only about 2,784, square miles of land in the U.S.
are devoted to railway infrastructure.
The linear nature of railway lines leads to the splitting of natural habitats, possibly decreasing habitat
size and reducing interaction between communities of species. Railway structures may damage
existing vegetation, interfere with wildlife crossings, displace communities of animals and birds,
and/or alter the hydrology of the area, such as drainage and stream flow patterns. Over time, rail lines
can act as long-terms dams, causing the buildup of wetlands in the area. Certain species may also
become accustomed to nesting along the right-of-way. When rail lines are abandoned, salvage
activities (such as the removal of track, bridges, or culverts) may cause wetlands destruction or
habitat disruption.
Measures can be taken, however, to mitigate environmental damage, such as route selection to bypass
particularly sensitive areas, compensatory habitat creation and relocation, fine adjustments to vertical
or horizontal alignments, and limiting salvage and construction activities to certain times and
locations. In 1993, the ICC conducted over 130 environmental reviews for rail abandonment cases
and imposed salvage restrictions in approximately 60 of these cases to mitigate impacts on
environmental resources (ICC, 1993). Limitations on salvage activities include restricting salvage to
certain times of year when species of concern are not present or breeding in the area, and limiting
salvage to the right-of-way to prevent disturbing nearby wildlife habitat.
Many heavy-rail systems have been constructed underground as subways, either through cut-and-
cover methods or tunneling. While subways typically are built in highly urban areas, this
construction may still have environmental impacts related to,drainage, soils, and geology.
CAUSAL FACTORS
* Miles of track constructed ~ ' - '.
* Miles of track abandoned and salvaged
* Current land use '
* Type of construction (elevated, at-grade, underground)
* Ecological conditions/type of land (i.e., wetlands, forest, etc.)
EMISSIONS DURING CONSTRUCTION AND MAINTENANCE
PRESENTATION OF INDICATORS
QUANTIFIED OUTCOME/RESULTS INDICATORS
* No data are available on the health or habitat effects of emissions from rail station
construction or laying of rail track.
101
-------
Indicators of the Environmental Impacts of Transportation
QUWIBSJ OUTPUT INDICATORS
4 National statistics for emissions from construction are not collected because of their
temporary and project-specific nature. They are unlikely to be large in national terms given
the limited amount of construction.
* Class I railroads laid 13,233,000 crossties and 441,38 1 tons of new rail in 1993 (AAR,
1993). Creosote is a toxic preservant that is applied to crossties.
Class 1 Railroads
Tons of New Rail Laid
2,500
1920 1940 1960 1980 2000
Source: AAR, 1994.
DESCRIPTION OF IMPACT
Construction or salvage of plant and equipment can affect the environment through diesel fumes
from excavating machinery and haulage vehicles, spillage during refueling, dust from earthworks,
and noise. In addition, construction traffic may also emit air pollutants.
CAUSAL FACTORS
* Miles of track constructed, tons of new rail laid
* Miles ,of track salvaged
• Level of construction and/or salvage activities
• Fuel consumed by construction equipment
* Topographical conditions (hills, valleys, etc.)
* Climatic conditions (temperature, wind, rain, etc.)
+ Population density
102
-------
The Indicators: Rail
2. RAIL CAR AND PARTS MANUFACTURE
The manufacture of railcars, locomotives, and parts results in environmental impacts through the
release of toxics to the air, soil, and water.
Toxic Releases
TOXICRELEASES
PRESENTATION OF INDICATORS
QUANTIFIED OUTCOME/RESULTS INDICATORS
* No quantified data on human health impacts, such as increased incidence of cancer from
toxics, or habitat and species impacts are available.
QUANTIFIED OUTPUT INDICATORS . '.-'.•
* Nearly 2.2 million pounds of toxic chemicals were reported released on-site from railroad
equipment manufacturing facilities in 1993 (U.S. EPA, 1995d).55
55
Impacts of imported equipment and parts are not counted here. Only U.S. facilities are included here,
including the impacts of exported equipment
103
-------
Indicators of the Environmental Impacts of Transportation
Toxic Chemicals Released from Railroad Equipment Manufacturing Facilities
(pounds per year)
SIC Industry
Code Type
3743 Railroad
Equipment
On-Site Releases
Air Water Land .Underground Total
Injection
2,157,138 458 15
500 2,158,111
Off-Site
POTW locations
Transfer Transfer
176,632 8,165,741
Source: U.S. EPA, 1993 Toxic Releases Inventory (1995)
DESCRIPTION OF IMPACT
The manufacture of railroad vehicles and engines involves use of a variety of materials and
chemicals. During the various processes, toxic'chemicals are released from vehicle manufacturing
facilities into the environment. Releases occur as on-site discharges of toxic chemicals, including
emissions to the air, discharges to water, releases to land, and contained disposal or injection
underground. In addition, chemicals are transferred off-site, as the following diagram shows.
On-Site Emissions
Air
Land
Off-Site
Transfers
Water
Underground
Injection
On-site releases to air occur as either stack emissions, through confined air streams, fugitive
emissions, which include equipment leaks, evaporative losses from surface impoundments and spills;
and/or releases from building ventilation systems. Surface water releases may include releases from
discharge pipes and from diffuse runoff from the plant facility's parking lots, roofs, and other areas.
Releases to land may include disposal in landfills, surface impoundments, and other types of land
disposal within the boundaries of the reporting facility. Underground injection is a contained release
of a fluid into a subsurface well.
Off-site transfers involve shipments of chemicals away from the reporting facility. Except for off-
site transfers for disposal, these quantities do not necessarily represent entry of the chemical into the
environment. Chemicals are often shipped to other locations for recycling, energy recovery, or
treatment at publicly owned treatment works (POTWs). Wastewaters are transferred through pipes
or sewers to a POTW, where treatment or removal of a chemical from the water depends upon the
nature of the chemical and treatment methods used. Some chemicals are destroyed in treatment.
104
-------
The Indicators: Rail
Others evaporate into the atmosphere. Some are removed but are not destroyed by treatment and
may be disposed of in landfills (U.S. EPA, 1992b). ; ,
CAUSAL FACTORS .
* Number of vehicles or parts built
4 Amount of chemicals, used in manufacture per vehicle or part
* Efficiency of processes and pollution prevention efforts
4 Amount of chemicals transferred to other locations for recycling, energy recovery, or
treatment
* Types of chemicals released and toxicity
4- Population density and extent of exposure
4 Environmental conditions such as climate and topography
105
-------
-------
The Indicators: Rail
3. RAIL TRAVEL
Rail transport directly affects the environment through emissions from fuel combustion, noise, and
hazardous materials incidents. These impacts are discussed below. In most cases, the amount of
travel (freight and passenger) is an activity indicator that provides a crude indication of the level of
effect. Additional data on rail travel activity are presented in Appendix A.
Exhaust
Emissions
EXHAUST EMISSIONS
PRESENTATION OF INDICATORS •.'•..
QUANTIFIED OUTCOME/RESULTS INDICATORS
* No data are available on the health or habitat effects of emissions from rail travel.
QUANTIFIED OUTPUT INDICATORS • .
. * In 1994, railroad operations were responsible for the following emissions nationwide (U.S.
EPA, 1995e):
Pollutant
Quantity Emitted
(1994, thousand
short tons)
Percentage of total
Emissions of that
Pollutant
Carbon Monoxide (CO)
Nitrogen Oxides (NOX)
Volatile Organic Compounds
(VOCs) '
Sulfur Dioxide. (SO2)
Paniculate Matter (PM-10)
Ammonia
124
947
43
69
48
1.79
0.13 %
4.01 %
0.19 % •
0.33 %
0.11 %"*
0.03 %
107
-------
Indicators of the Environmental Impacts, of Transportation
In 1993, CO2 emissions from railroad operations accounted for approximately 12 million
metric tons of carbon equivalent (mmtCe), or 0.9 percent of total national anthropomorphic
COa emissions (Apogee estimate).56
Railroad travel contributed to emissions of other greenhouse gases, as reported below (U.S.
EPA, 1994a):
Pollutant
Methane
Nitrous Oxide (N2O)
Quantity Emitted
(1990, thousand
metric tons)
2
1
CO Emissions from Railroads
Year
1970
1980
1985
1986
1987
1988
1989
1990
1991
1992
1993
1994
Thousand
Short Tons
65
96
106
109
112
118
121
122
122
124
124
124
Percentage of
Total National
Emissions
0.05 %
0.08 %
0.09 %
0.10 %
0.10 %
0.10 %
0.12%
0.12%'
0.13 %
0.13 %
0.13 %
0.13 %
CO Emissions
Source: U.S. EPA, 1995e.
in
I
o
to
o
140
120
100
80
60 •
40
20
0
1970 1975 1980 1985 1990 1995
Year
56 Estimate is based on the following methodology: transportation sector energy use by fuel type
within a mode (DOE/EIA, 1995b) was multiplied by carbon coefficients (mmtCe/quadrillion Btu) for
each fuel (DOE/EIA, 1995a), then adjusted by fraction of carbon that does not oxidize during
combustion (DOE/EIA, 1995a). Note that this estimate does not account for upstream emissions,
such as emissions from car assembly and fuel production.
108
-------
The Indicators: Rail
NOX Emissions from Railroads
.Year
1970 ,
1980
1985
1986
1987
1988
1989
1990
1991
. 1992
1993
• 1994 •
Thousand
Short Tons
495
731
808
829
854
897
923
929
929 .
. 946
945
947
Percentage of NOX Emissions
Total National , 1000 r— — -• - - ,
Emissions " Qm I ^ — • — •
2.40 % ' son I ^/ ,
.3.13% I 7m ^ .
3.53% - t: snn / •-.
3"71% 1 500 K
3.81% ,1 '
3-80% \ :
3'97% 1 -
4.03% ' ^°°
4.10% '°°
4 14 % ' •
4.06% Yoar
4.01% .
Source: U.S. EPA, 1995e.
VOC Emissions from Railroads
Year
1970
1980
1985
1986
1987
1988
1989
1990
1991
1992
1993
1994 '
Thousand '
Short Tons
22
33
37
38
39
41
42
42
42'
43
43
43 . ',
Percentage of VOC Emissions
rTt'rt+0l iSIo^irLnol^ 4*5 i
loiai ixauonai H0
Emissions ' 40 / /~~
0.07% „ ^
0.13% £ /
0.14% ^ £ 3° ' / ,
0.15% | 25 X
0.16% ? 20
0.16% ' "15
0.18% . 1 10
0.18%
0.18% 5
.19 % . . u •
nino/ iy/0 1980 1990 2000
U.iy /o Year
0.19% ;
Source: U.S. EPA, 1995e.
109
-------
Indicators of the Environmental Impacts of Transportation
SO2 Emissions from Railroads
Year Thousand
n; , „!> !' ::',! inl, &IIIL u V ' „, .
Short Tons
1970 36
1980 53
1985 59
1986 60
1987 62
1988 65
1989 67
1990 68
1991 68
1992 69
1993 69
1994 69
Percentage of
Total National
Emissions
0.12%
0.20%
0.25%
0.27%
0.28%
0.29%
0.29%
0.30%
0.31%
0.32%
0.32%
0.33%
70
60
01
g 50
|j 40
en
"g 30
n
CO
o 20
jc
10
0
19
SO2 Emissions
70 1980 1990 2000
Year
Source: U.S. EPA, 1995e.
PM Emissions from Railroads57
Year Thousand
•'. .Short Tons
1970 25
1980 37
1985 41
1986 42
1987 43
1988 45
1989 47
1990 47
1991 47
1992 48
1993 48
1994 48
Percentage of
Total National
Emissions
-
-
0.09%
0.08%
0.10%
0.07%
0.09%
0.11%
0.10%
0.11%
0.1-1%
0.11%
50
45
40
CO
o 35
r so
to 25
1 20
CO
i 15
f 10
5 -
PM Emissions
_^f-
i !
'1970 1975 1980 1985 1990 1995
Year
Source: U.S. EPA, 1995e.
QuAtmFiSDAcnvrrY INDICATORS
* Refer to Appendix A for data on rail travel.
37 Percentage of total emissions are not reported for paniculate matter prior to 1985 because of changes in total
emissions inventories; fugitive dust arid wind erosion are reported only for the period 1985 to 1994.
110
-------
The Indicators: Rail
DESCRIPTION OF IMPACT ' . •
Exhaust emissions from fuel combustion are a function of type and quantity of energy consumed.
Quantity of energy consumed, in turn, depends on fuel efficiency and distance traveled. Trains in the
U.S. generally burn diesel fuel, but some, particularly in passenger transport, use electric power
sources. Note that while electric trains themselves are "clean" and do not emit air pollutants, electric
generating facilities, depending on power source, may emit CO, NOX, PM, SOX, VOC, and CO2.
CAUSAL FACTORS
4 Vehicle miles of travel (VMT), by type of engine
* Fuel efficiency i ' • -
* Fuel consumed, by type .
* Emissions rates
V Topographical conditions affecting pollutant dispersion (hills, valleys, etc.)
* Climatic conditions affecting pollutant dispersion and formation (temperature, wind, rain,
etc.) •
* Population density-exposure to pollution
NOISE
PRESENTATION OF INDICATORS '
QUANTIFIED OurcoME/RESULTSjNDicATORS '
* . Less than 3 percent of the U.S. population in 1980 was exposed to noise levels from rail
operations great enough to cause annoyance—expressed in Leq greater than 55 dB(A) -
(OECD, 1993). A more recent estimate is not available.
. * A small portion of the U.S. population was exposed to daily noise levels from rail transport
great enough to cause other effects, such as communication interference, muscle/gland -
reaction, and changed motor coordination, as the following chart shows:
Percentage of U.S. Population Exposed to Rail Transportation Noise, 1980
Outdoor Sound Level in Leq [djB(A)l
>55 dB(A)
Annoyance
>60 dB(A)
Normal
Speech Level
>65 dB(A)
Communication
Interference
• ' * '
>70dB(A)
Muscle/Gland
Reaction
:>75dB(A)
Changed
Motor
Coordination
2.4% 1.4% 1.0% 0.2% n/a
Source: OECD, 1993. ' : '"_ :
111
-------
Indicators of the Environmental Impacts of Transportation
U.S. population exposed to
annoying" noise levels
from railroads: 3%
Source: OECD, 1993.
QtwmKED OUTPUT toontws
4 Noise levels are site specific and dissipate with increasing distance from the source; as a
result, an aggregate national noise emissions figure is not meaningful.
4 Typical noise emissions are 100 dB(A) for a diesel train, and 120 dB(A) for a locomotive
whistle (BTS, 1994).
QuwnReo ACTIVITYINDICATORS
4 Refer to Appendix A for data on rail travel.
DESCRIPTION OF IMPACT
Noise associated with rail transport comes from engine operations, rail-wheel contact, aerodynamic
effects, and vibrating structures during operations. The issue of noise is generally discussed in terms
of the number or proportion of people affected. The findings of numerous research projects in OECD
countries on the effects of noise and its wider repercussions indicate that an outdoor sound level of
65 dB(A) is "unacceptable," and an outdoor level of less than 55 dB(A) is desirable (OECD, 1993).
Although at the national level, railroad noise does not appear to be a significant problem, at the local
level, noise impacts from rail may be severe depending on population density near rail lines and
frequency of operations.
CAUSAL FACTORS
• Level of rail activity (miles of travel, frequency of service) by rail type
4 Speed
4 Population density near rail
4 Distance between population/housing and rail operations
4 Background noise level
4 Natural noise barriers (topography, vegetation)
4 Designed noise barriers and control devices
HAZARDOUS MATERIALS INCIDENTS DURING TRANSPORT
PRESENTATION OF INDICATORS • •
QUANTIFIED OUTCOME/RESULTS INDICATORS
4 No statistics were found regarding the number of species or acres nationwide affected by
commodity spills.
112
-------
The Indicators: Rail
QUANTIFIED OUTPUT INDICATORS
* An average of 1,172 hazardous materials spills occurred annually during rail transport in the
U.S. between 1990 and 1994, some of which were recovered (HMIS, 1995) (see table and
graphic).
Distribution of'Gallons of Hazardous Materials
Spilled in Rail Transport, 1990-1994
Misc. Hazardous Material
20%
Combustible
Liquid
16%
Flammable -
Combustible
Liquid
41%
Corrosive Material
• ,23%
Source: HMIS, 1991
113
-------
Indicators of the Environmental Impacts of Transportation
Hazardous Materials Rail Incidents, Annual Average, 1990-94
Class
Corrosive Material
Flammable - Combustible Liquid
Nonflammable Compressed Gas
Flammable Gas
Combustible Liquid
Oxidizer
Miscellaneous Hazardous Material
Poisonous Materials
Poisonous Gas
Other Regulated Material, Class E
Flammable Solid
Flammable Solid (per-1991)
Spontaneously Combustible
Dangerous when Wet Material
Other Regulated Material, Class C
Other Regulated Material, Class A
Very Insensitive Explosive
Radioactive Material
Total
Number of
Incidents
523.6
288.6
102.2
76.0
64.4
36.0
28.0
23.0
12.2
5;8
3.6
2,2
2.0
1.6
. 1.2
1.0
0.2
0.2
1,171.8
Gallons
Released
91,002.8
165,626.3
40,942.2
10,965.3 ,
63,107.3
1,721.0
14,096.9
8,524.5
4.8
12.5
55.3
0.2
0.0
0.3
40.6
7,401.1
0.0
0.0
'403,701.0
Pounds
Released
714.1
1.6
416,904.7
65,599.8
34,107.6
0.6
100,041.2
248.8
1,009.8
20,586.2
544.4
220.5
20.0
639,999.2
Cubic Feet $ Clean-up Cost
Released and Loss of
Material
1,459,253
3,323,142
506.0 98,560
, 843.2 314,359
813,559
696,681
156,403
2,492,427
0.1 283,551
225,128
9,985
222,404
79,179
22,400
2,000
349,403
10
0
1,349.2 10,548,645.2
Source: HMIS Database
* The quantity of hazardous materials remaining in the environment after cleanup efforts is
unknown.
OTHER Quwnweo DATA AM LOCAL EXAMPLES
4 For Class I railroads in 1993, chemicals and allied products accounted for 135,063 tons (9.7
percent) of freight originated. Petroleum and coke accounted for 40,132 tons (2.9 percent)
originated (AAR, 1993).
4 Of the 1,130 hazardous materials rail incidents reported to HMIS in 1991, 41% resulted
from human error, 50 percent from packaging failure, 5 percent from vehicle
accidents/derailments, and 4 percent from other causes (HMIS, 1991).
* Class I claims for freight loss and damage, including non-hazardous commodities, accounted
for only 0.34 percent of Class I freight revenue in 1993 (AAR, 1993).
DESCRIPTION OF IMPACT
The potential for commodity spills during rail transportation is important to consider because of the
large, albeit decreasing, role rail plays in domestic freight movement. In 1993, rail transport
accounted for 46 percent of the ton-miles and 29 percent of the tonnage moved during domestic
intercity transport, excluding pipelines (Eno, 1994). In particular, commodity spills of hazardous
materials may impose substantial costs for product loss, carrier damage, property damage,
evacuations, and response personnel and equipment. The Hazardous Materials Information System
(HMIS) database, maintained by U.S. DOT/Research and Special Projects Administration (RSPA),
114
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The Indicators: Rail
contains a record of all reported hazardous materials incidents occurring during rail transport,
including type of material released, number of injuries/fatalities, and estimated cleanup costs.'
The number of hazardous material incidents is not necessarily indicative of the environmental impact
of such incidents, since it may be possible to clean up most of the materials released. If not properly
contained, however, hazardous materials incidents may cause long-term environmental damage such
as water pollution, damage to fish and wildlife, habitat destruction, and aesthetic or recreational
losses.. The environmental impact of any given hazardous materials spill is highly site-specific. It
depends on the type and quantity of material spilled, amount recovered in cleanup, chemical
properties (such as toxicity and combustibility), and impact area characteristics (such as climatic
conditions, flora and fauna density, and local topography). It should be noted that while the overall
impact of rail spills may be small for the nation as a whole, any hazardous material spill may have
severe impacts on flora and fauna in the location of occurrence.
CAUSAL FACTORS
* Quantity of hazardous materials transported and distance transported
4 Accident or spill rate •
* Type and quantity of materials spilled
4- Cleanup efforts , :
4 Population density
* Sensitivity of local habitats/species
115
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The Indicators: Rail
4. RAIL CAR MAINTENANCE AND SUPPORT
Besides trains and track, rail transport requires, support facilities such as terminal areas, fueling
stations, and electric generating facilities (to power electrified passenger rail systems).
Emissions from
Utilities powering Rail
Releases during Terminal Operations:
Cleaning and Maintenance
RELEASES DURING TERMINAL OPERATIONS: CAR CLEANING, MAINTENANCE, REPAIR, AND
REFUELING
PRESENTATION OF INDICATORS
^QUANTIFIED OUTCOME/RESULTS INDICATORS
4 Data on water quality impacts on streams, rivers, and lakes, and related habitat due to rail
terminal operations are not available. Data on health effects from air pollution coming from
terminals are also not available. . .
QUANTIFIED OUTPUT INDICATORS
* Tank car and rail car cleaning operations emit 1.25 million pounds of VOCs per year (EPA
„ Source Assessment Study of 1978 as cited in U.S. EPA, 1995).
4 Quantified estimates of other emissions are not known nationally. However, a variety of
wastes are known to be generated from typical railroad terminal operations.
117
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Indicators of the Environmental Impacts of Transportation
Typical Railroad Terminal Operations:
Materials Used and Types of Waste Possibly Generated
Process/Operation
Materials Used
Types of Waste Generated
Unloading or
Cleaning of Tank
Cars
Rust Removal
Painting
Paint Removal
Exterior Washing
Equipment degreasing
Refueling
Solvents, alkaline cleaners
Naval jelly, strong acids,
strong alkalies
Enamels, lacquers, epoxies,
alkyds, acrylics, primers,
solvents
Solvents, paint thinners,
enamel, white spirits
Solvents, cleaning solutions
Degreasers, engine cleaners,
acids, alkalies, cleaning
fluids
Diesel fuel
Acid/alkaline wastes
Toxic wastes
Solvent wastes
Residual tank contents
Acid/alkaline wastes
Ignitable wastes
Toxic wastes
Paint wastes
Solvent wastes
Paint wastes
Toxic wastes
Solvent wastes
Solvent wastes
Oil and grease
Ignitable waste
Combustible solids
Acid/alkaline wastes
Evaporative losses
Fuel drips and spills
Source: U.S. EPA/RCRA Fact Sheet: Motor Freight/Railroad Terminal Operations, 1993; U.S. EPA, 1995
QUAtmFtsoAcmnY INDICATORS
4 Approximately 90 percent of transportation equipment cleaning facilities discharge
wastewater to POTWs or combined treatment works (privately owned by multiple facilities)
after some amount of treatment. Some facilities discharge directly to surface waters under
NPDES permits or to underground injection wells under Safe Drinking Water Act permits
(U.S. EPA, 1995).
DESCRIPTION OF IMPACT
Terminal operations include line haul railroad activities (such as tank car unloading and cleaning,
equipment degreasing, exterior washing, and painting), furnishing of terminal facilities for passenger
or freight traffic, and the movement of railroad cars between terminal yards. Many of these processes
use materials that are hazardous or may in turn generate hazardous waste or wastewater. In addition,
refueling operations impact the environment through spills and drips of fuel, and through fuel tank
vapors that are displaced when the tank is filled with liquid fuel. The actual impact of terminal
activities on the environment depends in a large part on the type and volume of operations, level of
cleanliness required, type of waste generated, and efficacy of wastewater treatment.systems in place.
The cleaning of rail tank interiors is a major source of pollution during terminal operations. The
typical rail tank car has a volume of 20,000-30,000 gallons and generates about 3,000-5,000 gallons
of wastewater during cleaning, resulting in the output of spent cleaning fluids, fugitive VOC
118
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The Indicators: Rail
emissions, water treatment system sludges, and tank residues. The disposal and treatment of tank
heels can also be a source of pollution for tank cleaning facilities. The typical heel volume of a rail
tank car (i.e., amount left in tank after unloading) is 10-30 gallons per tank, and a facility's
wastewater treatment system may be adversely affected by, or may not adequately treat, a slug of
concentrated tank residue. Incompatible heels are usually segregated and resold to a reclaimer or
shipped off-site for disposal. Heels that are composed of detergents, solvents, acids, of alkalis can be
stored on-site and used as tank cleaning fluids or to neutralize other tank heels.
Relatively small amounts of waste and wastewater are generated from the washing and maintenance
of rail car exteriors. Typical hazardous wastes generated include spent solvents, spent caustics, paint
chips, and paint sludges. Wastewater is generally treated pn-site and then discharged to a public
treatment works (U.S. EPA, 1995).
The primary source of toxic chemicals released are substances dissolved or suspended in wastewater,
primarily during the cleaning of tank interiors. Other potential environmental impacts of terminal
operations include air emissions and residual wastes. Fugitive emissions of VOCs arise from tank
heels and residues, cleaning solutions, painting and paint stripping, and refueling vapors. Residual
wastes are generated as sludges from wastewater treatment systems, residues removed from the
inside of tanks, and hazardous wastes from painting, paint removal, and cleaning of parts (U.S. EPA,
1995). '
CAUSAL FACTORS
* Number of terminals
* Type and level of terminal operations
4 Materials used during terminal operations
4 Wastewater treatment capabilities
EMISSIONS FROM UTILITIES POWERING RAIL*
PRESENTATION OF INDICATORS '
QUANTIFIED OUTCOME/RESULTS INDICATOBS
4 No data are available on the health or habitat effects of emissions from utilities powering
rail..
QUANTIFIED OUTPUT INDICATORS
* Rail transport's share of emissions from electric utilities accounts for less than 0.01 percent
of total national emission's of CO, NOX, TP, SOX, VOC, and lead (U.S. EPA, 1995e; DOE,
1994a). !
58 Emissions from utilities powering rail could also be categorized as part of rail travel, but they are
listed here because utilities are legally stationary sources, and emissions do not occur near the point
of travel.
119
-------
Indicators of the Environmental Impacts of Transportation
Rail Share of Emissions from Electric Utilities, 1992
Type of Emission
National Emissions
from Utilities
(thousand short tons)
RailShare (0.2%)
of Utility Emissions
(thousand short
tons)
Percentage of Total
National Emissions
from Rail
CO
NOx
Total Particulates (TP)
SOX
VOC
Lead
313
7,473
255 «
15,417
34
0.059
0.63
14.95
0.51
30.8
0.07
<0.01
< 0.01 %
<0.01 %
< 0.01 %
< 0.01 %
< 0.01 %
<0.01 %
Source: U.S. EPA, 1993a; DOE, 1994a
QuANmso ACTIVITY INDICATORS
«• Passenger rail transport accounted for 0.2 percent of total national electric consumption in
1992. Electric rail did not consume any nuclear or hydro-electric power in 1992 (U.S. DOE,
1994a).
* Passenger rail transport consumed 59.8 trillion Btu of electricity in 1993, compared with
21.6 trillion Btu of diesel fuel (U.S. DOE, 1995c)
DESCRIPTION OF IMPACT
To the extent that passenger transport by rail is the only significant transportation-related consumer
(excluding pipelines) of electricity for fuel, and that electricity provides about 75 percent of the
energy used in such operations, emissions from utilities should be considered when evaluating the
environmental impacts of rail. The contribution of electric rail transport to atmospheric pollution
depends of the type of power source used to generate electricity.
While air pollution from nuclear and hydro-electric power stations is minimal, coal and other fossil
fuel power plants emit large quantities of NOX, SOX, and paniculate matter, as well as smaller <
amounts of CO, VOC, and lead. Such power plants may be significant contributors to acid rain, for
example. Water pollution from nuclear, coal, and other fossil fuel power plants consists primarily of
thermal discharges from cooling water, which can cause substantial adverse impacts to water
chemistry, habitat, and species. Thermal discharges are regulated under the Clean Water Act.
Hydro-electric power stations affect the flow and temperature of rivers by retaining water in
reservoirs.
CAUSAL FACTORS
* Electrified rail VMT
4 Quantity of electricity consumed (total or per VMT)
* Power source/technology used to generate electricity
4 Emissions controls at power plants
4 Topographical conditions (hills, valleys, etc.)
4 Climatic conditions (temperature, wind, rain, etc.) •
4 Population density
120
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The Indicators: Rail
5. DISPOSAL OF RAIL CARS AND PARTS
RAIL CAR AND PARTS DISPOSAL
PRESENTATION OF INDICATORS
QUANTIFIED OUTCOME/RESULTS INDICATORS
4 Estimates are not available on the health and environmental impacts of landfilling or other
disposal of scrapped rail cars and parts.
QUANTIFIED OUTPUT INDICATORS ,
* National data on emissions from the disposal of vehicles are not available.
QUANTIFIED ACTIVITY INDICATORS ' " • '
4 Each year, 35,000 new rail cars are installed, suggesting that a comparable number are
scrapped or exported annually since the .fleet size is not increasing significantly. (AAR,
1993). . ,
DESCRIPTION OF IMPACTS ' .
Rail cars and their parts—such as nickel-cadmium batteries, metals, spent oil—are scrapped,
refurbished or recycled'as they wear out. In addition, many rail cars and their components are
exported. However, disposal practices may allow the release of toxic substances into water, air, or
soil,
CAUSAL FACTORS
* . Quantity of metals and Oil used in rail operations.
* Recovery rate
* Groundwater contamination and seepage prevention measures at the disposal site
121
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-------
The Indicators: Aviation
AV1A"TIQN
This section presents the quantitative indicators available for tracking the nationwide environmental
impacts of aviation. There are three key environmental issues for which there is enough quantitative
data to produce national indicators. Other types of environmental impacts are identified and
intermittently tracked by airports, states, and EPA through individual environmental impact
statements (EISs), but data are not consolidated at the national level. For each of the five basic
categories of activities affecting the environment, the various impacts are listed.
HOW EACH IMPACT IS PRESENTED IN THIS SECTION
Each environmental impact is covered in one or more pages of text and graphics, with the following
key subsections:
* Presentation of indicators
The key indicators that have been quantified are presented. Outcome
indicators are listed first since they provide information on end results and
are theoretically the most desirable type of indicator. Unfortunately, actual
quantified data are often unavailable or of poor quality. In many instances,
the only available data on outcomes are the number of states reporting a
problem. This information is often incomplete (not all states may examine the
problem), vague (states may define the problem differently), or only
somewhat relevant (the contribution of transportation to the problem may be
unknown). As a result, output indicators—such as emissions data—are
presented. These statistics may be an easier and more valid measure for
policy makers to examine and track over time. Activity indicators (defined
broadly to include infrastructure, travel, and other activities) are listed when
they are the best available indicators or when outcome and output indicators
are not adequate. In some cases, local examples are also provided.
To avoid repetition within the report, basic infrastructure and travel
indicators are listed in Appendix A for each mode of transportation.
Appendix B contains additional relevant statistics on monetized values of
health and other impacts; these outcome indicators are listed separately since
there is generally more uncertainty regarding these figures.
* Description of impact
The nature of the impact is briefly defined and explained here. More
complete descriptions of these impacts are available in reference works listed
in the bibliography.
123
-------
Indicators of the Environmental Impacts of Transportation
+ Causal factors: Variables that change over time and between locations
Policy makers find it very useful to understand the driving forces behind
environmental impacts. Understanding the key causal factors, such as VMT or
emissions rates in grams per mile, is critical to explaining observed trends in
indicators. They also help in estimating how local impacts may differ from national ,
averages. These causal variables, then, explain how the impacts differ over time and
geographic location. Most importantly, they suggest potential policy levers. Policies
can be designed to focus on any of the key variables (e.g., grams emitted per mile)
that determine the magnitude of an environmental impact.
The following table provides an overview of the available indicators for each impact. It is important to
note two points about what is included hi this table: First, indicators are listed only where they have
been quantified at the national level; if an impact has not been quantified, no "potential" indicator is
listed here. For each specific activity and its impact, the table provides a summary of the availability
of quantitative data for indicators of outcomes, output, and activity. Second, the table shows only the
best indicator for each impact rather than listing various alternative types of indicators for a given
impact. The exceptions are when multiple indicators are needed to address all aspects of an issue or
where some indicators are otherwise insufficient. Although outcome indicators are theoretically the
most desirable type of indicator, actual quantified outcome data are often unavailable or of poor
quality. As a result, output indicators—such as emissions levels—tend to be the most reliable and
valid measures available in most cases. Activity indicators are presented in this table when they are
the best available indicators or when outcome and output indicators are not adequate.
124
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The Indicators: Aviation
1, AIRPORT CONSTRUCTION, MAINTENANCE, AND EXPANSION
Airport construction, maintenance, and expansion result in a number of environmental effects.
Common problems associated with infrastructure include habitat disruption, hydrologic alterations,
introduction of deicing compounds to the environment, and increased runoff. In addition, airport
construction activities may have temporary environmental impacts, such as air pollutant emissions
from construction equipment, These impacts are discussed below, and further material on
infrastructure is available in Appendix A.
Air Pollutant Emissions during
, Construction/maintenance
Habitat Disruption
Airport Runoff
affecting Water
'Quality1
Application of
De-icing
Compounds
/ /I
HABITAT DISRUPTION AND LAND TAKE
PRESENTATION OF INDICATORS.
QUANTIFIED OUTCOME/RESULTS INDICATORS - - • • •
* The number of species or acres of sensitive habitat adversely affected by airport construction
and expansion is not known.
QUANTIFIED OUTPUT INDICATORS
+ No quantified data are readily available on the amount of land taken annually or
cumulatively by airport runways and other infrastructure.
QUANTIFIED ACTIVITY INDICATORS -•
4 Only one major scheduled passenger service airport (Denver, International Airport) has been
constructed since 1974. However, the total number of airports (including private airports) in
127
-------
Indicators of the Environmental Impacts of Transportation
the U.S. has increased by about 3,182 from 1980 to 1994—a nearly 21 percent increase—
from 15,161 in 1980 to 18,343 in 1994 (BTS, 1994). .
* In 1994, there were planned construction activities at 60 major airports for approximately
1,022,350 feet (194 miles) of new runway/taxiway (FAA, ACE Plan, 1994). Generally, this
construction will be done over a period of five or more years.
* There were 18,343 airports in the U.S. in 1994, which is more airports than in eyery other
nation in the world combined (BTS, 1994).
* Airports vary significantly in size. The U.S. contains 26 large hub airports (handling 1
percent or more of total air passenger enplanements) and 570 commercial service airports
(2,500 or more enplanements "annually) (BTS, 1994).
Owe? QUANTIFIED DATA AW LOCAL EXAMPLES
* A typical major new airport requires approximately 25,000 acres of land (Wood and
Johnson, 1989). .
4 Runway construction at Dallas/Fort-Worth International Airport was expected to
significantly affect some natural features and resources. Wetlands that existed on the
property included drainage-ways, creeks, and small isolated systems that would be affected
by runway construction (U.S. DOT, DFW Air Development Plan, 1991).
DESCRIPTION OF IMPACT
Airport construction and expansion activities have the potential to affect endangered or threatened
species. Impacts on wildlife from construction activity depend on the extent and types of habitat that
are disturbed and the availability of comparable habitats near the site. Long term impacts from
increased airport surfaces include elimination of and damage to existing vegetation, interference with
wildlife, displacement of forests and communities of animals and birds, and alteration in the
hydrology of various areas.
CAUSAL FACTORS
4 Number of new airports constructed
* Number of runway and other airport capacity enhancements
4 Ecological conditions/type of land (i.e., wetlands, forest, etc.) "
• Successful airport implementation of various efforts to avoid or mitigate impacts (i.e.,
stormwater treatment)
EMISSIONS DURING CONSTRUCTION AND MAINTENANCE
PRESENTATION OF INDICATORS
Qttt/vneeo OUTCOME/RESULTS INDICATORS
* No data are available on the health or habitat effects of emissions from airport construction
or maintenance.
QUWOTJED OUTPUT INDICATORS
V National statistics for emissions from airport-related construction activities are generally not
available. At the local level, emissions from construction are discussed on a case-by-case,
basis in the project's EIS.
128
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The Indicators: Aviation
QUANTIFIED ACTIVITY INDICATORS . •
'4 Only one major scheduled passenger service airport (Denver International Airport) has been
constructed since 1974.
* In 1994, there were planned runway/taxiway construction activities at 60 major airports for
approximately 1,022,350 feet (194 .miles) of new runway/taxiway (FAA, ACE Plan, 1994).
Generally, this construction will be done over a period of five or more years.
4 Thenumber of airports in the U.S. has increased by about 3,182 from 1980 to 1994—a
nearly 21 percent increase—from 15,161 in 1980 to 18,343 in 1994 (BTS, 1994).
4 National data on the amount of fuel consumed during airport construction and maintenance
have not been identified.
DESCRIPTION OF IMPACT
Construction-related activities generally result in temporary visual, noise, air quality, erosion, water
quality, and solid waste impacts. Emissions during airport construction and expansion are associated
with land clearing, blasting, ground excavation, earth moving; cement, asphalt, and aggregate
handling; heavy equipment operation; use of haul roads; and wind erosion of exposed areas and
material storage piles. The quantity of emissions from construction operations is proportional to the
area of land being worked and the level of construction activity. Dust emissions, a large portion of
which result from equipment traffic over temporary roads at the construction site, may have
substantial temporary impacts on local air and water quality.
Construction can also affect the environment through exhaust emissions from machinery and haulage
vehicles, spillage during refueling, and noise. The environmental impact of any particular project
depends on the condition of the surrounding area, the size of airport, and the length of project
duration. Temporary storage facilities for equipment and supplies used during the construction phase
may also damage vegetation and displace communities of animals.
Hazardous waste on airport property (especially older army and air force bases) is another type of
problem associated with airport construction and expansion. Sometimes the problem is discovered
when a major 'construction project unexpectedly runs into hazardous material.
Often, airport construction, maintenance and operations are-themselves the source of hazardous waste
problems due to the use of hazardous materials, .such as lead paint, solvents, and pesticides.
CAUSAL FACTORS . •
* Number of new airports constructed
4 Number of runway and other airport capacity enhancements
4 Ecological conditions/type of land (i.e., wetlands, forest, etc.)
4 Successful airport implementation of various efforts to avoid or mitigate impacts (i.e.,
stormwater treatment)
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Indicators of the Environmental Impacts of Transportation
RELEASES OF DEICING COMPOUNDS
PRESENTATION OF INDICATORS
QtavBRS? OUTCOME/RESULTS INDICATORS >
• No data are available to quantify the extent to which deicing chemicals in airport runoff
cause groundwater contamination and habitat or health effects.
OUWTJRED
4 Deicing one aircraft typically results in the pollution load about equal to the daily wastewater
of 5,000 people (Backer, et al, 1994).
4 A recent survey shows that 46 percent of the airports discharge runway runoff directly into
public waterways without treatment or monitoring (Airport Magazine, March/April 1991).
4 As much as 64 to 100 percent of applied urea may discharge directly to surface waters
through overland flow (D'ltri, 1992).
4 Some 75 percent of glycol used at airports ends up in surface drainage during spring thaw
(Eady, 1990).
QUANTtFKDAcmTY INDICATORS
* Based on the 1989-90 season, the nationwide use of deicing products is estimated at 1 1.5
million gallons per year (D'ltri, 1992).
* The amount of deicer required per aircraft ranges from 10 gallons to several thousand gallons
(D'ltri, 1992).
* Mean annual glycol usage at airports surveyed is 44,589 gallons (AAAE).
* Large airports can use over 150,000 gallons of deicer in a single storm event (D'ltri, 1992).
OTHER QuwnBeo DATA AND LOCAL EXAMPLES
4 Of the deicing solution applied to aircraft, it is estimated that 49 to 80 percent falls to the
apron (D'ltri, 1992).
4 Organic, alcohol-based chemicals used to de-ice airplanes at the Des Moines International
Airport are winding up in Yeader Creek every winter, according to state and airport officials.
As they decompose, the compounds take oxygen out of the water, harming small fish and
algae and helping an unsightly fungus (Des Moines Register, November 19, 1993).
4 Glycol-based deicing fluid has recently (March 1996) been connected to onion-like odors at
Milwaukee's General Mitchell International Airport. Toll operators have complained of
similar odors, headaches, nausea, sore throats, and itchy eyes from Boston's Logan
International Airport (ENR, March, 1996).
4 At Logan International Airport, deicing runoff flows into storm drains and is discharged
untreated into nearby areas, including Boston Harbor (ENR, March,, 1996).
4 In Milwaukee, untreated deicing fluid flows across 400 acres of airport land and drains into
Lake Michigan (ENR, March, 1996).
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The Indicators: Aviation
DESCRIPTION OF IMPACT • •
Airports' wintertime use of deicing chemicals on aircraft and runways/taxi ways is beginning to
receive greater attention. Aircraft deicers used in North America have formulations based on ethylene
or propylene glycol. Runway deicers are typically formulated with urea and glycols. As mentioned
above, it is estimated that 11.5 million gallons of deicing products are used every year. Of the deicing
solution applied to aircraft, it is estimated that 49 to 80 percent falls to the apron. The amount of
deicer required per aircraft ranges from 10 gallons to several thousand gallons.
Urea and glycols may rapidly appear in stormwater runoff or.temporarily remain in snow piles. The
aquatic toxicity of ethylene and propylene glycols is relatively low and oral toxicity to humans and
• terrestrial.life is also relatively low. Presence of ethylene glycol in the environment as puddles,
howeyer, may pose hazards to animals attracted to its sweet taste. Although none of the glycols used
in deicers have been shown experimentally to be harmful, the animal carcinogen 1,4-dioxane does
occur as a trace contaminant in technical grade ethylene glycol. Although glycols are biodegradable
under normal conditions, the biodegradation is so rapid and oxygen demanding that they can affect
oxygen-dependent aquatic life in receiving waters.
The urea that is used in runway deicers Degrades to ammonia and the ammonia is converted to nitrate.
Although both of these processes are slowed considerably at wintertime temperatures, the formation
of ammonia and nitrate from urea pose environmental concerns. The toxicity of ammonia to aquatic
life is high and excessive nitrate exposure through contaminated drinking water can be hazardous to
humans (D'ltri, 1992).
Unless captured in on-site collection basins or discharged to a municipal wastewater treatment plant,
glycol and urea may mix with runway and other local sources of stormwater resulting in pn-site
puddling and soil infiltration, overland flow, and release to surface waters.
CAUSAL FACTORS ' ,
* Amount of aircraft/runway deicing agents applied
* Type of deicing agent used
. * Climate/weather conditions (amount of snow, ice, rainfall) .
* Amount of high salinity rainfall/snowmelt that reaches bodies of water (based on runoff
controls and local geography) .
4 Depth of ground water table •
* Sensitivity of nearby habitats
AIRPORTRUNOFF
PRESENTATION OF INDICATORS' .
QUANTIFIED OUTCOME/RESULTS INDICATORS
* No data are available to quantify the extent to which airport runoff causes groundwater
contamination, impairment of water quality in rivers and lakes, and habitat or health effects.
QUANTIFIED OUTPUT INDICATORS
, 4 No data are readily available to quantify the pollutant loading of runoff from airports.
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Indicators of the Environmental Impacts of Transportation
QfMmnsD ACTIVITY INDICATORS
* There were 18,343 airports in the U.S. in 1994, which is more airports than in every other
nation in the world combined (BTS, 1994).
* Most airports are small private-use airports, many of which have unpaved runways, as the
following table shows:
U.S. Airports, 1992
Public-Use Airports
Private-Use Airports
Total All Airports
Number
5,545
12,301
17,846
Percentage
with Paved
Runways
71.7
36.6
47.5
Percentage
with Lighted
Runways
72.3
7.6
27.7
Source: BTS, 1994
4 High flows from a nearby airport during major storm events are believed to be responsible
for displacing juvenile fish from the Des Moines Creek.
DESCRIPTION OF IMPACT
Water quality in wetlands and streams may be affected by construction and post-construction
activities. Stormwater run-off from runways/taxiways, aprons, roads and parking lots, for example,
will result in an increase in pollutant loading to wetlands and streams unless stormwater treatment
facilities are included as part of airport construction. An increase in the amount of such impervious
surface area and the elimination of recharge areas such as wetlands affects the low flow
characteristics of steams by reducing groundwater recharge capabilities. This may result in the
reduction of carrying capacity of streams and elevated water temperatures, which, in turn, may
increase stress levels in fish, as well as reduction in feeding and growth levels.
CAUSAL FACTORS
* Number of airports and paved surface area
* Number of runway and other airport capacity enhancements
* Precipitation activity
4 Drainage characteristics
* Ecology and other aspects of receiving water bodies: type, size, diversity, potential for
dispersion
* Successful implementation of mitigation efforts (i.e., stormwater treatment)
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The Indicators: Aviation
2. AIRCRAFT AND PARTS MANUFACTURE
The manufacture of aircraft and parts results in environmental impacts through- the release of toxics to
the air, soil, and water., . ,
toxic Releases
TOXIC RELEASES
PRESENTATION OF INDICATORS
QUANTIFIED OUTCOME/RESULTS INDICATORS
* No quantified data on human health impacts, such as increased incidence of cancer from
toxics, or habitat and species impacts are available.
QUANTIFIED OUTPUT INDICATORS •
4- 28.7 million pounds of toxic chemicals were reported released on-site from aircraft
manufacturing facilities in 1993 (see table).59
59
Impacts of imported equipment and parts are not counted here. Only U.S. facilities are included here,
including the impacts of exported equipment. •
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Indicators of the Environmental Impacts of Transportation
Toxic Chemicals Released from Aircraft Manufacturing Facilities and Related Sources
(Pounds per Year)
SIC Industry Type
Code
3720 Aircraft & Parts
3721 Aircraft
3724 Aircraft Engines &
Engine Parts
3728 Aircraft Part & Auxiliary
Equipment, NEC
4581 Airports, Flying Reids &
Airport Terminal Services
TOTAL AIRCRAFT
On-Site Releases
Air Water Land
75,790
12,239,470 4,917 81
5,848,914 ' 50,519 122
10,331,033 2,465 81,210
60,000
28,495,207 57,901 141,413
Total
75,790
12,244,468
5,899,555
10,414,708
60,000
28,694,521
POTW Transfer Off-Site
Locations
Transfer
14,339
125,166 4,632,947
31,527 18,165,359
87,773 6,594,777
244,466 29,947,422
Source: Toxic Releases Inventory, 1993
POTW = Publicly owned treatment works
SIC = Standard Industrial Classification
* The top five pollutants (by volume) reported (SIC code 3721) released include methyl ethyl
ketone, trichloroethane, dichloromethane, tetrachloroethylene, and toluene. These are
solvents used to clean equipment and metal parts, and are used in many coatings and finishes
(U.S. EPA, 1995f).
* At one plant where the aircraft painting hangar was used as a test site, approximately 51 tons
of VOCs were emitted per year (based on 1988 emission estimates), representing
approximately 7 percent of the total VOC emissions (on a mass basis) into the air from the
plant, and making the hangar the second largest source of airborne VOC emissions at the
plant (Larsen and Pilat, September 1991).
QtwmfJED ACTIVITY INDICATORS
* Between 1990 and 1993, 947 new jet aircraft were delivered to U.S. customers (Boeing,
1993).
Omen QUWTIPHD DA TA AND LOCAL EXAMPLES
* In July 1991, Lockheed joined EPA's 33/50 Program, agreeing to voluntarily reduce releases
and transfers of targeted chemicals by 33 percent in 1992 and by 50 percent in 1995, using
1988 as a baseline year. Based upon 1988 figures, these reductions would total 1,820,094
and 2,757,718 pounds, respectively. In the 1988 baseline year, Lockheed companies reported
releases and transfers of 6,842,485 pounds of all TRI chemicals (U.S. EPA's, 1995f).
* By eliminating chlorinated solvent usage in metal cleaning, printed circuit board coating
operations, and hazardous chemical use during paint stripping by using plastic media
blasting, Lockheed surpassed its 33/50 Program commitment far in advance of set deadlines,
reporting 1,298 pounds of releases and transfers of 33/50 Program chemicals in 1993,
compared with 5,515,435 pounds in 1988'. This reduction included a complete elimination of
releases and transfers of cadmium compounds, lead compounds, and tetrachloroethylene.
The other major contributors to Lockheed's success include the following reductions:
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The Indicators: Aviation
Chemical
Amount Reduced
Dichloromethane
Methyl Ethyl Ketone
Methyl Isobutyl Ketone
Toluene
1,1,1 - Tricholorethane
Trichloroethylene
Xylene •
88,085 pounds (51 percent)
115,371 pounds (80 percent)
23,128 pounds (80 percent)
, 74,884 pounds (86 percent)
293,493 pounds (73 percent)
482,103 pounds (76 percent)
73,198 pounds (85 percent)
• Source: U.S. EPA, 1995f.
DESCRIPTION OF IMPACT
The manufacture of aircraft involves use of a variety of materials and chemicals. During the
manufacturing process, toxic chemicals are released from vehicle manufacturing facilities into the
environment. Releases occur as on-site discharges of toxic chemicals, including emissions to the air,
discharges to water, releases to land, and contained disposal or injection underground. Chemicals are
transferred off-site when they are shipped to other locations, as the following diagram shows.
On-Site Emissions
Air
Land
Off-Site
Transfers
Water
Underground
Injection
On-site releases to air occur as either stack emissions, through confined air streams such as stacks or
vents, or fugitive emissions, which include equipment leaks, evaporative losses from surface
impoundments and spills, and releases from building ventilation systems. Surface water releases may
include releases to rivers, lakes, oceans, and other bodies of water. Releases to land may include
Jandfills, surface impoundments, and other types of land disposal within the boundaries of the
reporting facility. Underground injection is a contained release of a fluid into a subsurface well for
the purpose of waste disposal.
Off-site transfers represent a movement of the chemical away from the reporting facility. Except for
off-site transfers for disposal, these quantities do not necessarily represent entry of the chemical into
the environment. Chemicals are often shipped to other locations for recycling, energy recovery, or
treatment. Transfers often are to publicly owned treatment works (POTWs). Waste waters are
. transferred through pipes or sewers to a POTW, where treatment or removal of a chemical from the
water depends upon the nature of the chemical and treatment methods used. Some chemicals are
135
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Indicators of the Environmental Impacts of Transportation
destroyed in treatment. Others evaporate into the atmosphere. Some are removed but are not
destroyed by treatment and may be disposed of in landfills (U.S. EPA, 1992).
CAUSAL FACTORS
* Number of aircraft built
* Amount of chemicals used per aircraft
* Efficiency in mitigation efforts
4 Types of chemicals released and toxicity
4- Population density and extent of exposure
* Environmental conditions such as climate, topography, or hydrogeology affecting fate and
transport of chemicals into the environment
136
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The Indicators: Aviation
3. AVIATION TRAVEL
Air travel has increased at a rate of 5.0 percent per year over the past decade and is expected to
continue at this rapid pace over the next decade. In fact, Boeing projects that world air travel will
increase by 70 percent over the next 10 years. Boeing estimates that 15,900 aircraft will be added to
the world,fleet by 2015. This significant growth has important implications for aircraft noise and
atmospheric emissions.
High Altitude
Emissions
Low Altitude
Emissions
HIGH ALTITUDE EMISSIONS
PRESENTATION OF INDICATORS . , .
QUANTIFIED OUTCOME/RESULTS INDICATORS
* In terms of global warming, NOX emitted from aircraft above 10,000 feet have up to 5Q times
the effect of NOX emitted closer to the ground (WWF, 1991).
* Quantitative data on the amount of global warming and stratospheric ozone loss due to high
altitude aircraft emissions are not available.
137
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Indicators of the Environmental Impacts of Transportation
Owmw OUTPUT INDICATORS
4 In 1993, CO2 emissions from aviation accounted for approximately 45 million metric tons of
carbon equivalent (mmtCe), or 3 percent of total national CO2 emissions (Apogee
estimate).60
4 Air transport is responsible for at least 2 percent of anthropogenic CO2 emissions (EDF,
1994).
* Aviation contributed to emissions of other greenhouse gases, as reported below (U.S. EPA,
1994a):
Pollutant
Quantity Emitted
(1990, thousand
metric tons)
Methane (CEU)
Nitrous Oxide (N2O)
negligible
4 Although environmental significance varies by altitude, most pollutants are emitted by
aircraft at all levels. For data on total emissions of NOX, CO, VOC, SO2, and PM, by aircraft,
see the following section on "Ground Level Emissions." These data are not broken down by
altitude.
* The nation's commercial airlines consumed 16 billion gallons of jet fuel in 1992 (Business
Dateline; Minneapolis/ St. Paul City Business).
4 Aircraft consume about 2.5 percent of fossil fuel used (Green and Santini, 1993).
4 Energy use by air carriers has increased significantly since 1970, totaling over 2,144 trillion
Btu in 1992 (see table and graphic). However, energy use per passenger mile has decreased
by 58 percent since 1970 (U.S. DOE, 1994a).
Energy Use By Air Carriers8'
Year Energy Use
(trillion Btu)
Energy Use By Air Carriers
1970
1363.4
1975
1283.4
1980
1489.6
1985
1701.5
1990
2191.3
1991
2069.2
1970 1975
1992
2144.2
Source: U.S. DOE. 1994a.
1980 1985
Year
1990 1995
*° Estimate is based on the following methodology: transportation sector energy use by fuel type within a mode
(DOE/EIA, 1995b) was multiplied by carbon coefficients (mmtCe/quadrillion Btu) for each fuel (DOE/EIA,
1995a), then adjusted by fraction of carbon that does not oxidize during combustion (DOE/EIA, 1995a). Note
that this estimate docs not account for upstream emissions, such as emissions from aircraft assembly and fuel
production; refer to DeLuchi, 1991, for carbon coefficients needed to compute total fuel-cycle CO2 emissions.
Energy use includes fuel purchased abroad for international flights.
138
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The Indicators: Aviation
* Aviation is one of the few petroleum users projected to have a continuing growth in fuel
consumption of approximately 30 percent from 1990 to 2000 worldwide (Green and Santini,
1993). ,
* Fuel dumping is typically done above 10,000 feet so that the fuel will evaporate before
reaching the ground. But even small amounts of pollution at that altitude can amount to much
bigger problems, scientists believe (Business Dateline; Minneapolis St. Paul City Business).
.OTHER QUANTIFIED DATA AND LOCAL EXAMPLES ,
4 On at least 68 occasions in 1992, Northwest jets dumped fuel before they could get down to
a safe landing weight. The airline dumped about 471,500 gallons of jet fuel and lost about
$300,000 in the process (Business Dateline; Minneapolis St. Paul City Business).
DESCRIPTION OF IMPACT
Aircraft emissions can occur at three altitude zones: (1) the boundary layer, (2) the upper troposphere,
and (3) the lower stratosphere. CO2, NOX, CO, VOC, SO2, and PM are emitted by aircraft at all
altitudes. With the exception of CO2, their environmental significance varies on the altitude of
emission (EDF, 1994). There is, however, a great deal of uncertainty in the quantity of pollution
emitted by aircraft at different altitude levels.
Aircraft spend most of their time in the cruise mode, directly injecting most nitrogen oxides into the
higher levels of the atmosphere (WWF, 1994). According the World Meteorological Organization
(WMO), the addition of NOX to the atmosphere is expected to decrease ozone in the stratosphere.
Also, NOX emissions are expected to increase ozone in the troposphere, which may be a cause of
global warming. In terms of ozone formation, NOX emissions from aircraft may have 50 times the
effect per unit emitted compared with surface level anthropogenic emissions (WWF, 1991). The
resulting changes in ozone, water vapor, and aerosol loading in the altitudes around the tropopause
may have a climatic impact.
Anthropogenic NOX emissions also contribute to acid rain which may have a direct effect on wildlife,
ecosystems, and buildings, although aircraft account for less than 2 percent of total anthropogenic
NOX emissions, the tremendous growth in air travel may have future implications on acid rain.
Water vapor emissions may lead to increases in the formation of high altitude clouds, which act as a
potential global warming agent. Water vapor emissions may also increase the formation of polar
stratospheric clouds that are implicated in ozone loss and the formation of the ozone hole (WWF,
1994).
Although other gases are emitted by aircraft at all altitudes, carbon dioxide, methane, and nitrous
oxide are described here in order to describe the major greenhouse gases together. It is estimated that
CO2 emissions from aircraft account for about 2-3 percent of the total global emissions from fossil
fuels. According to the World Wildlife Fund (WWF), CO2,emissions are responsible, for at least 2
percent of global warming. In addition, according to WWF, NOX and water from aircraft may be as
large as their emissions of CO2.
It is also believed that the dumping of jet fuel can cause severe hydrocarbon pollution, which
contributes toward global warming (Business Dateline; Minneapolis/St. Paul City Business). Fuel
139
-------
Indicators of the Environmental Impacts-of Transportation
dumping is typically done above 10,000 feet so that the fuel will evaporate before reaching the
ground. However, scientists believe that even small amounts of pollution at that altitude can amount
to more significant problems than at lower levels (Business Dateline; Minneapolis/St. Paul City
Business).
CAUSAL FACTORS
* Altitude of aircraft in cruise mode
* Type of aircraft and engine
* Number of aircraft
4 Quantity of fuel dumped at 10,000 feet
LOW ALTITUDE/GROUND LEVEL EMISSIONS
PRESENTATION OF INDICATORS
Qwnmso OUTCOM&RESULTS /NOKMTORS
» No data are available on the health or habitat effects of low altitude emissions by aircraft.
In 1994, aircraft operations were responsible for the following emissions nationwide (U.S.
EPA, 1995e): >
Pollutant
Carbon Monoxide (CO)
Nitrogen Oxides (NO*)
Volatile Organic Comp. (VOCs)
Sulfur Dioxide (SO2)
Particulate Matter (PM-10)
Butadiene*
Quantity Emitted
(1994, thousand
short tons)
1,063
153
212
8
48.
107 short tons
Percentage of total
Emissions of that
Pollutant62
1.08 percent
0.65 percent
0.91 percent
0.04 percent
0.11 percent
0.10 percent
*Note: Butadiene estimate is for 1990; units are in short tons.
62 Note: percentages are based on anthropogenic emissions, except for PM-10, which includes natural emissions.
140
-------
The Indicators: Aviation
Year
1970
1980
1985
1986
1987
1988
1989
1990
1991
1992
1993
1994
CO Emissions from Aircraft
Thousand Percentage of
Short Tons Total CO
Emissions
506 0.40%
743 0.64%
831 0.72%
858 , 0.79%
887 0.82%
931 ' 0.80%
955 0.93%
966 0.96%
962 0.99%
980 1.04%
1,019 ' 1.08%
1,063 ' 1.08%
CO Emissions
-|OQO
«, 1000
* 800. •
o ^^^
w 600 ^^
r -^
| 400
o
jE 200
0
.
1970 1975 1980 1985 1990 1995
Year
Source: U.S. EPA, 1995e.
NOX Emissions from Aircraft
Year
. 1970
1980
'1985
1986
1987
1988
1989
1990
1991.
1992
1993
1994
Thousand Percentage of
Short Tons Total NOX
, • Emissions
• 72 . 0.35%
106 0.46% •
119 0.52%
123 0.55% .
128 0.57%
134 0.57%
138 0.59%
139 , 0.60%
139 0.61%
141 0.62%
147 0.63%
153 0.65%
NOX Emissions
160 —
I
140 !
: | »|. -
r 100 |. ^^
0 ^^^
• W. 80 -L-^^"^
i -r
o 40 ! .
H 20 j
0 • '
j
1970 1975 1980 1985 1990 1995
Year
Source: U.S. EPA, 1995e.
141
-------
Indicators of the Environmental Impacts of Transportation
VOC Emissions from Aircraft
;TYear
1970
1980
1985
1986
1987
1988
1989
1990
1991
1992
1993
1994
Thousand Percentage of
Short Tons Total VOC
1 " ; ' .";• "";• ; ' Emissions
97 0.32%
146 0.56%
165 0.64%
170 0.68%
176 0.71%
185 0.72%
190 0.79%
192 0.81%
192 0.84%
195 0.87%
203 0.90%
212 0.91%
Source: U.S. EPA, 1995e.
SO2 Emissions from Aircraft
Year
lii
1970
1980
1985
1986
1987
1988
1989
1990
1991
1992
1993
1994
Thousand Percentage of
Short Total SO2
Tons Emissions
4 0.01%
6 0.02%
6 0.03%
6 0.03%
7 0.03%
7 0.03%
7 0.03%
7 0.03%
7 0.03%
7 0.03%
8 0.04%
8 0.04%
VOC Emissions
^^n ,,,,,, „ , „ , L
\
£ 200 j ^/ 1
° ' ^^~^ l
5 150 ^-^"^ j
•^ ^^"^ \
in • ^^ — !
? 100 -"•""^
CO ' ' '
en
5 50 :
1- '• '
1970 1975 -1980 1985 1990 1995
Year
SO2 Emissions
18
« 16
£ 14
' 5 12
OT 10 •
| 8 T. . ' • • • ' /- •
^— —— — —
i 4— — -
"•«
1970 1975 1980 1985 1990 1995
Year
Source: U.S. EPA, 1995e.
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The Indicators: Aviation
Particulate Matter (PM-10) Emissions from Aircraft
63
Year Thousand Percentage
Short Tons of Total PM-
10 Emissions
1970
1980
1985
1986
1987
1988
1989
1990
1991
1992
1993
1994
21
33
37
38
40
42
43
44
44
44
46
48
-
-
0.08%
0.08%
Q.10%
0.07%
0.08%
0.10%
0.09%
0.10%
0.11%
0.11%
Particulate (PM) Emissions
1970 1975 1980 1985 1990 1995
Year
Source: U.S. EPA, 1995e.
QUANTIFIED ACTIVITY INDICATORS
4 Refer to Appendix A for data on vehicle travel.
DESCRIPTION OF IMPACT ' • . * •
Ground-level emissions result from five specific modes in the landing and takeoff cycle (LTO):
* Approach
4 Taxi/idle-in
4 Taxi-idle-out .
* Takeoff
4 Climb-out >
The factors that determine the quantity of pollutants emitted by aircraft depend on the duration of
each operating mode and the fuel consumption rate. HC and CO emissions are very high when the
aircraft is in taxi-idle mode. Emissions fall when the aircraft moves into higher power operating
modes (CEPA, 1994). NOX emissions, on the other hand, are low when engine power is low but
increase as power level is increased. In addition, particulate emissions are higher at low power rates
and improve at higher engine power. The table below presents the LTO cycle times for the three
commercial aircraft types:
63 Percentage of total emissions are not reported for particulate matter prior to 1985 because of changes in total
emissions inventories; fugitive dust and wind erosion are reported only for the period 1985 to 1994.
143
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Indicators of the Environmental Impacts of Transportation
Default Time-in-Mode for Commercial Aircraft (minutes)
Aircraft Taxi/ Takeoff Climb- Approach Taxi/ Total
idle-out out idle-in
Jumbo, long & medium
range jet
Turboprop
Transport-piston
19.0
19.0
6.5
.07
.05
0.6
2.2
2.5
5.0.
4.0
4.5
4.6
7.0
7.0
6.5
32.9
33.5
23.2
The nature of pollutants emitted by aircraft is the same as those emitted by on-road mobile sources.
Similar to on-road mobile sources, carbon monoxide (CO), sulfur oxides (SOX), nitrogen oxides
(NO,), volatile organic compounds (VOC), and particulate matter (PM) are all byproducts of the
combustion process. These pollutants affect the environment, health, and welfare by causing
respiratory and other illnesses, reduced visibility, and soiling and corrosion of materials. They also
affect the environment by causing adverse effects on ecosystems including damage to crops, forests,
and other terrestrial and aquatic plants and animals. Although CO2 is not harmful to human health or
habitat directly, it is an important greenhouse gas that contributes to global warming.
Certain chemicals interact ip the air to create secondary chemicals. Ozone is a key secondary
pollutant, caused by the interaction of NOX and VOCs. In addition, the combination of sunlight, water,
and chemicals like SO2, NOX, and HCs can form secondary particulate matter.
It is important to note, however, that these pollutants are also emitted by other sources, including
motor vehicles, dry cleaning establishments, and painting factories. In fact, aircraft only account for a
small percentage of the pollutants emitted. The quantity of pollutants emitted from aircraft operations
is a function of the type of aircraft and engine, mode of operation, and how long the engine is
operated in each mode.
CAUSAL FACTORS
* Number of aircraft
* Type of aircraft/engine type
* Landing and take-off cycle (LTO) cycle
t Airport congestion levels
4 Meteorological conditions
NOISE
PRESENTATION OF INDICATORS
QuwnRED Otrco«MsH£SW.7S INDICATORS
* In 1989, FAA estimated that 3.2 million people lived in noise-impacted areas, which the
agency defines as receiving noise levels of DNL 65 or above (DNL = day-night sound level,
a common measurement of community noise exposure (GAO-ns).64
M DNL represents an energy-averaged sound level for a 24-hour period measured from midnight to midnight
after adding 10 decibels to nighttime noise events between 10 p.m. and 7 a.m.). It is equivalent to Ldn.
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The Indicators: Aviation
4 Population exposed to day-night noise level (DNL) of 65 dB or greater from aircraft has
fallen from approximately 7.0 million to 1.7 million, largely due to the phasing out of Stage 2
aircraft and increased use of Stage 3 aircraft.
Population Exposed
to DNL 65 dB
Population Exposed DNL 65 dB
Year
Population in
Millions
1975
7.0
1980'
5.2
1985
3.4
1990
2.7
1995
1.7*
2000
0.4*
1994
Predicted 62.0% Stage 3
Actual
2000
*Prediction based on Stage 3
implementation
Source: FAA, 1995b.
* About 9 percent of the U.S. population in 1980 was exposed to noise levels from aircraft
great enough to cause annoyance—expressed in Leq greater than 55 dB(A)] (OECD, .1993).
* A small portion of the U.S. population was exposed to daily noise levels from aircraft great
enough to cause other effects, such as communication interference, muscle/gland reaction,
and changed motor coordination, as the following chart shows:
Percent of U.S. Population Exposed to Aircraft Noise, 1980
Outdoor Sound Level in Leq [dB(A)]
>55 dB(A)
Annoyance
>60 dB(A)
Normal Speech
Level
>65dB(A)
Communication
Interference
>70dB(A)
Muscle/Gland
Reaction
>75dB(A)
Changed Motor
Coordination
9.0 percent 4.0 percent
2.0 percent
0.4 percent
0.1 percent
Source: OECD, 1993.
QUANTIFIED OUTPUT INDICATORS
* Noise levels are site specific and dissipate with increasing distance from the source; as a
result, an aggregate national noise emissions figure is not meaningful.
* Typical noise emissions at takeoff and landing are:
Aircraft
Propeller
DC 10
727 -
707
.747
Takeoff, dBA
88
90
97
102
104
Landing, dBA
78
83
87 ,
95
93
Source: BTS, 1994.
145
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Indicators of the Environmental Impacts of Transportation
* Refer to Appendix A for data on aviation travel.
OTHER QUWTCRED DA TA AND LOCAL EXAMPLES
* According to an 1985 FAA report, a one decibel increase in DNL usually results in a 0.5 to
2.0 percent decrease in property values (GAO). '
* In September 1992 and in May 1994, the City of Grapevine conducted surveys within the
Sunshine Harbor subdivision immediately north of the Dallas/Fort Worth Airport. The
surveys had the following results:
- 94 percent of the respondents indicated that their normal activities (i.e., watching TV,
talking on the phone) were interrupted by noise (September 1992 survey); 92 percent in
the May 1994 survey.
— 64 percent of the respondents indicated that their sleep was regularly interrupted by
aircraft noise (September 1992 survey); 71 percent in the May 1994 survey.
- 61 percent of respondents indicated that their quality of life had been effected, in some
way by the operation of the Dallas/Fort Worth Airport. Of those responses, noise
pollution was ranked as the number one problem affecting quality of life.
— 19 percent of the respondents indicated that their children had been endangered outdoors
because of noise levels. Most felt that this is because the children cannot hear cars
coming down the street.
DESCRIPTION OF IMPACT
The widespread introduction of jet aircraft in the 1960s and the tremendous growth in airline traffic
after deregulation in 1978 resulted in a considerable increase in aircraft noise. Noise is the most cited
and recognized environmental impact from aircraft and significantly affects millions of people in the
U.S. every day. As a result, most of the nation's predominantly jet airports developed noise control
programs. The federal government also issued regulations defining three classes of aircraft in terms of
their noise levels:
Stage 1: aircraft certified before 1969 that do not meet the noise standards issued in that year
Stage 2: aircraft meeting the 1969 standards
Stage 3: aircraft complying with the latest standards issued in 1977
Because of the long operating life of commercial jets, the FAA issued a new rule in 1976 to phase out
all Stage 1 aircraft by 1985.
Although all aircraft designs certified after March 1977 had to meet Stage 3 noise standards, Stage 2
designs continued to be manufactured until 1988. As a result, Stage 2 aircraft are still widely in use
and consist of about 45 percent of the U.S. air carrier fleet as of December 31, 1994. In 1990, new
legislation was introduced to phase out Stage 2 aircraft. This legislation set the phase-out of Stage 2
aircraft by the end of 1999 (FAA, 1994 Progress Report).
There are three main documented environmental effects of aviation noise:
1. Hearing loss is a well-documented effect of noise in general, but is not generally a concern in
community airport noise problems. Even in a very noisy airport environment, the duration of
noise is not sufficiently long to cause hearing loss. The Occupational Safety and Health
Administration (OSHA) has defined a noise exposure limit of 90 dBA for 8 hours per day to
146
-------
The Indicators: Aviation
prevent hearing loss. The typical indoor maximum noise level in the 65 dBA noise contour will
range from 55 to'75 dBA.
2. Communication and sleep interference are also major environmental concerns associated with
aircraft noise. These interferences lead to a difficult to quantify "annoyance" factor, since people
respond differently to noise. In general, however, annoyance can be measured based on the types
of activities disrupted by the noise (i.e., speech or sleep interference).
3. Some research also points to physiological, psychological, and social behavior problems
stemming from noise effect on humans (FAA, 1985). These effects, however, are subject to
debate, but generally include changes in pulse rate and blood pressure. Some studies have pointed
to increased risk of hypertension as well as other stress related problems. There is some evidence
to show that noise may have the greatest impacts on children and those with a variety of mental
illnesses.
In addition, aircraft noise has also been shown to affect real estate values, land use, wildlife and farm
animals (FAA, 1985).
CAUSAL FACTORS •
4 Number of aircraft operations .
4 Population in area affected by aircraft noise
4 Number of Stage 2 aircraft
4 Aircraft flight path ,
4 Aircraft glide path
HAZARDOUS MATERIALS INCIDENTS DURING TRANSPORT
PRESENTATION OF INDICATORS
QUANTIFIED OUTCOME/RESULTS INDICATORS
4 No statistics were found regarding the number of species or acres nationwide affected by
commodity spills.
QUANTIFIED OUTPUT INDICATORS
4 An average of 256 gallons and 477 pounds of hazardous materials were reported released
during aviation transport between 1990 and 1994.
4 An average of 518 releases were reported annually, more than 60 percent of which consisted
of flammable-combustible liquid. . . .
147
-------
Indicators of the Environmental Impacts of Transportation
Aviation Hazardous Material Incidents, Annual Average, 1990-1994
Class
Flammable - Combustible Liquid
Corrosive Material
Poisonous Materials
Misc. Hazardous Material
Other Regulated Material, Class D
Nonflammable Compressed Gas
Flammable Gas
Other Regulated Material, Class A
Radioactive Material
Oxidizer
Combustible Liquid
Organic Peroxide
Infectious Substance (Etiologic)
Flammable Solid
Flammable Solid (pre 1991)
Other Regulated Material, Class B
Dangerous When Wet Material
Explosive Projection Hazard
Explosive No Blast Hazard
Poisonous Gas
Other Regulated Material, Class E
Explosives, Class A
Explosives. Class C
Total
Number of
Incidents
316.2
92.2
30.2
18.0
15.6
10.0
9.6
4.8
4.2
4.0
2.8
2.2
2.2
1.2
1.2
1.2
0.8
0.4
0.4
0.4
0.4
0.2
0.2
518.4
Gallons
Released
174.8
48.0
13.8
8.4
1.0
2.9
0.9
1.3
0.0
0.4
6.8
0.0
0.0
0.1
0.2
0.1
258.9
Pounds
Released
11.0
0.4
23.3
59.3
5.3
9.2
223.1
•11.0
0.0
4.4
4.8
0.4
15.3
8.8
100.0
476.4
Cubic feet • Clean-up Cost and
Released Loss of Material
29,431
51,177
17,070
4,433
1,075
582
417
147
80.9 991
514
3,205
50
100
7
0
7,393
110
0.
120
0
40
100
0
80.9 116,961
Source: HMIS
* Aviation accounted for only 3.2 percent of all transportation-related hazardous materials
incidents reported to HMIS in 1991 (HMIS, 1991).
* The quantity of hazardous materials remaining in the environment after cleanup is unknown.
OTHER QuwmzD DATA AND LOCAL EXAMPLES
* Of the 293 aviation-related incidents reported in 1991, 76 percent resulted from human error,
15 percent from packaging failure, and 28 percent from other causes, not including vehicle
accidents. No incidents occurred as a result of vehicle accidents (HMIS, 1991).
DESCRIPTION OF IMPACT
Hazardous materials releases during aviation may occur en route, as well as during the
loading/unloading process. Hazardous materials incidents may cause environmental damage such as
air and water pollution, damage to fish and wildlife, and habitat destruction. The environmental
impact of any given hazardous material release is highly site-specific. It depends on the type and
quantity of material released, amount recovered in cleanup, chemical properties (such as toxicity and
combustibility), and impact area characteristics (such as climatic conditions, flora and fauna density,
and local topography). While the nationwide impact of hazardous materials releases from aviation
may be small, any hazardous materials incident may have severe impacts on the flora and fauna in the
location of occurrence.
148
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The Indicators: Aviation
CAUSAL FACTORS • '
* Type and quantity of hazardous material transported
4 Number of incidents .
4 Quantity of material released
4 Toxicity/hazard of materials released
4 Effectiveness of cleanup efforts
4 Population density
4 Sensitivity and location of affected ecosystems
149
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-------
The Indicators: Aviation
4. AIRPORT OPERATION
The growth in air travel has increased at a rapid pace over the past decade. Although airports account
for only a small portion of total regional, environmental impacts, the growth in air travel has raised
concern that airport-generated environmental impacts will continue to increase. It is important to note
that only one new major airport has been built since 1974. This, in turn, raises concerns that
congestion levels at major airports will continue to increase. Airport operations include cleaning,
maintenance, repair, and fueling of aircraft, as well as baggage handling and other cargo support
services. Environmental impacts of these operations include air emissions from ground support
equipment, fuel spills, oil leakages, and emissions of toxic substances.
Emissions from
Ground Support
Equipment
EMISSIONS FROM GROUND SUPPORT EQUIPMENT INVOLVED IN AIRCRAFT LOADING, CLEANING,
MAINTENANCE, REPAIR, AND REFUELING
PRESENTATION OF INDICATORS
' QUANTIFIED OUTCOME/RESULTS INDICATORS
* No national data are available on the health or habitat effects of emissions from airport
ground support equipment. .
QUANTIFIED OUTPUT INDICATORS
4 Emissions from ground support equipment (GSEs) range from 2-6 percent of total
emissions at commercial airports (CEPA, 1994).
151
-------
Indicators of the Environmental Impacts of Transportation
CO Emissions from Airport Service
Year
1970
1980
1985
1990
1991
1992
1993
1994
Thousand
Short Tons
33
48
54
62
62
63
65
68
Percentage Total
Emissions from
Airport Service t:
0.03% | 60 _^___ _— -***-**
0.04% c g 40 __— — *~~
0.05% 3 "~ 20 "
0.06% £ 0
0-06% 1970 1975 1980 1985 lggo 1995
0-07%
0.07%
0.07%
Source: U.S. EPA, 1995e.
NOx Emissions from Airport Service
Year
1970
1980
1985
1990
1991
1992
1993
1994
Thousand
Short Tons
1! |J -•'•' ;;•! "
78
113
125
144
144
146
152
159
Percentage ^emissions
Total Emissions
«. .'. . ?flO ... »,.,,„,„ M „•,,.,.,„ • • • „,»„,„,,-
from Airport r
Service g 150 ^++++*
0.38% ? § 100 ^-— ^—- ^^
0.49% . % "- so * | ' .
0.55% . 5 i
Jr_ Q I .„ . I „„„„,. „„„„„„.,„„„„•
0-63% 1Q7n 1P7C; 1pftn 1PRE; 1qqn -(Qprq
0.64%
0.64% Y"
0.65% • - • --- • ", - •• -
0.67%
Source: U.S. EPA, 1995e.
VOC Emissions from Airport Service
Year
1970
1980
1985
1990
1991
1992
1993
IOQ4
Thousand
Short Tons
9
13
15
17
17
17
18
18
Percentage ..^.^. _ . .
Total Emissions VOC Em.ssions
from Airport „
••'_'.-• r on
Service - o rT".j*-»
0.03% t 15 ^___-*— " ***j
0.05% | 10.^-— ~"*
0.06% 1 _ •
0.07% S
0 07% £
.:,,'..':,,.... I- 1970 1975 1980 1985 1990 1995
0.08%
0.08% Yeai
0.08% .... . .. ._ ....
Source: U.S. EPA, 1995e.
152
-------
The Indicators: Aviation
Particulate Matter (PM-10) Emissions from Airport Service65
Year , Thousand Percentage
Short Tons Total Emissions
from Airport
Service
Particulate (PM) Emissions
1970, '
1980
1985
1990
1991
1992
1993
1994 '
8.
12
13
15
15
16
16
17
-
-
0.03%
0.03%
0.03%
0.04%
0.04%
0.04%
1970 1975
1980 1985 1990
Year
1995
Source: U.S. EPA, 1995e. . ' • •
DESCRIPTION OF IMPACT ,
A variety of ground support equipment (GSE) are used to move, service, load, fuel, and power aircraft
at airports:
4 Baggage tractors
* Aircraft tractors •
4 Ground power units .
4 Air-conditioning units
4 Air start units ,
4 Baggage conveyors
4 Auxiliary power units
4 Other secondary GSE (forklifts, deicing vehicles, lavatory vehicles, fuel vehicles, etc.)
The majority of GSE have engines that operate on gasoline, diesel, or LPG (most APUs burn jet fuel).
Like on-road mobile sources, GSE have tailpipe, evaporative, and crankcase HC emissions. NOX and
PM are also emitted from the tailpipe.,Their effects on the environment, therefore, are similar to on-
road mobile sources and aircraft (CEPA, 1994).
Other environmental impacts associated with airport operations include fuel, oil, and other substance
spills, as well as release of toxic chemicals. These releases occur during aircraft cleaning,
maintenance, repair, and refueling.
CAUSAL FACTORS
. 4 Number of aircraft support vehicles
4 Type of fuel used and size of engine
4 Distance traveled by aircraft support vehicles \
4 Number of trips (operations)/number of cold starts
4 Fuel efficiency
4 Type and level of maintenance operations
65 Percentage of total emissions are not reported for paniculate matter prior to 1985 because of changes in total
emissions inventories; fugitive dust and wind erosion are reported only for the period 1985 to 1994.
153
-------
Indicators of the Environmental Impacts of Transportation
Materials used during maintenance operations
Wastewater treatment capabilities
154
-------
The Indicators: Aviation
5. DISPOSAL OF AIRCRAFT AND PARTS
AIRPLANE AND PARTS DISPOSAL
PRESENTATION OF INDICATORS
QUANTIFIED OUTCOME/RESULTS INDICATORS
+ Estimates are not available on the healtbi and habitat impacts of landfilling or other disposal
of scrapped airplanes and parts.
QUANTIFIED OUTPUT INDICATORS . ,
* No data are readily available on the amount of aircraft and parts disposed annually.
QUANTIFIED ACTIVITY INDICATORS - • "
4 World air carriers placed orders for an estimated 490 large jet aircraft with U.S. and foreign
aircraft manufacturers during FY 1995, 54.0 percent more orders than in 1994. Aircraft
manufacturers delivered approximately 449 large jet aircraft worldwide in 1995 (Boeing,
1995). Although the air carrier fleet is increasing, the increase in aircraft suggests that as
they reach the end of their lifecycle, additional aircraft and parts will be either disposed or
recycled. "
DESCRIPTION OF IMPACT
Disposal of airplanes and parts consists of refuse from the use and maintenance of aircraft and ground
support equipment, as well as other sources. In general, this waste includes batteries, tires, brake pads,
and other used vehicle components. Data on the amount of waste are unavailable on the national level.
Airplanes often are shifted to other uses when retired from commercial service, or are exported. This
fact, coupled with the longevity of the current fleet of airplanes, results in relatively low rates of
scrappage.
155
-------
Indicators of the Environmental Impacts of Transportation
CAUSALFACTORS
* Number of aircraft scrapped
* Quantity of metals and oil used in operations
* Disposal method/recovery rate of materials
4 Groundwater contamination and seepage prevention measures at the disposal site
156
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The Indicators: Maritime
ASi IT i n i EH VI-B b« H ij»j A L-* I n oYc A TO R s
This section presents the quantitative indicators available for tracking the nationwide environmental
impacts of maritime transportation. In this report, maritime transportation is defined to include all
water-borne mobile sources, such as ocean-going vessels, inland barges, and recreational boats. For
each of the five basic categories of activities affecting the environment, the various impacts are listed.
HOW EACH IMPACT IS PRESENTED IN THIS SECTION
Each environmental impact is covered in one or more pages of text and graphics, with the following
key subsections:
* Presentation of indicators
The key indicators that have been quantified are presented. Outcome
indicators are listed first since they provide information on end results and
are theoretically the most desirable type of indicator. Unfortunately, actual
quantified data are often unavailable or of poor quality. In many instances,
the only available data on outcomes are the number of states reporting a
. problem. This information is often incomplete (not all states may examine the
problem), vague (states may define the problem differently), or only
somewhat relevant (the contribution of transportation to the problem may be
unknown). As a result, output indicators—such as emissions data—are
presented. These statistics may be an easier and more valid measure for.
policy makers to examine and track over time. Activity indicators (defined
broadly to include, infrastructure, travel, and other activities) are listed when
they are the best available indicators or when outcome and output indicators
are not adequate. In some cases, local examples are also provided.
To avoid repetition within the report, basic infrastructure and travel
indicators are listed in Appendix A for each mode of transportation.
Appendix B contains additional relevant statistics on monetized values of
health and other impacts; these outcome indicators are listed separately since
there is generally more uncertainty regarding these figures.
* Description of impact
The nature of the impact is briefly defined and explained here. More'
complete descriptions of these impacts are available in reference works listed
in the bibliography.
* Causal factors: Variables that change over time and between locations
Policy makers find it very useful to understand the driving forces behind
environmental impacts. Understanding the key causal factors is critical to explaining
157
-------
Indicators of the Environmental Impacts of Transportation
observed trends in indicators. They also help in estimating how local impacts may
differ from national averages. These causal variables, then, explain how the impacts
differ over time and geographic location. Most importantly, they suggest potential
policy levers. Policies can be designed to focus on any of the key variables (e.g.,
grams emitted per mile) that determine the magnitude of an environmental impact.
The following table provides an overview of the available indicators for each impact. It is important to
note two points about what is included in this table: First, indicators are listed only where they have
been quantified at the national level; if an impact has not been quantified, no "potential" indicator is
listed here. For each specific activity and its impact, the table provides a summary of the availability
of quantitative data for indicators of outcomes, output, and activity. Second, the table shows only the
best indicator for each impact rather than listing various alternative types of indicators for a given
impact. The exceptions are when multiple indicators are needed to address all aspects of an issue or
where some indicators are otherwise insufficient. Although outcome indicators are theoretically the
most desirable type of indicator, actual quantified outcome data are often unavailable or of poor
quality. As a result, output indicators—such as emissions levels—tend to be the most reliable and
valid measures available in most cases. Activity indicators are presented in this table when they are
the best available indicators or when outcome and output indicators are not adequate.
158
-------
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The Indicators: Maritime
1. CONSTRUCTION AND MAINTENANCE OF NAVIGATION IMPROVEMENTS
In order to allow passage for various types of marine vessels, some waterways require navigation
improvements. The most common navigation improvement is dredging. Development and
maintenan'ce of navigation improvements can cause serious environmental harm. Problems include
degradation of habitats, hydrologic alterations, contaminated sediments, and deterioration of water
quality. These impacts are discussed below.
Habitat Disruption
and Contamination
from Disposal of
Dredged Material
Direct Deterioration of
Habitat and Water Quality
from Dredging and other
Navigation Improvements
Land Take and
Habitat Disruption
for Ports and
Marinas
DIRECT DETERIORATION OF HABITATS AND WATER QUALITY FROM DREDGING OR OTHER
NAVIGATION IMPROVEMENTS
PRESENTATION OF INDICATORS
QUANTIFIED OUTCOME/RESULTS INDICATORS • . •
«• In 1992, nine states reported that dredging was a source of wetlands loss (Council on
Environmental Quality, 1993). ,
* Between 5 and 15 percent of surface waters (and aquatic life in them) are affected by
hydrorriodification projects (Griffin, 1991). Note that only a portion of hydromodification
projects have a primary purpose of allowing or improving maritime transportation. Many
hydromodification projects are implemented for other purposes, such as water supply,
recreation, hydroelectric power production, and flood control.
* Of 14 reporting states, 9 listed channelization as a source of wetlands degradation in 1992
.(U.S.EPA, 1994b).66 . • ' ' '
66
The portion of channelization projects constructed to improve maritime navigation is unknown.
161
-------
Indicators oftlie Environmental Impacts of Transportation
QUWWJHJ OUTPUT INOKATOFIS
Dredged material generated in the U.S. is estimated to total between 400 and 480 million
cubic yards annually, based on a number of studies (Cullinane et al., 1990).
Based on studies from the mid 1980s, 79 percent of dredged material is generated by
maintenance projects, and 21 percent is generated by new work. (Cullinane et al., 1990) 84 to
101 million cubic yards of dredged material, therefore, are generated annually by new work,
and 316 to 379 million cubic yards are from maintenance projects (Apogee estimate).
Sediments from maintenance dredging are more likely than sediments from new work to be
contaminated because they are composed of recent deposits. Sediments that originate from
new work, on the other hand, are cleaner because they were deposited before
industrialization of the U.S. (U.S. EPA, 1989b).
Lower-bound Estimates of Annual Quantities Dredged
from U.S. Waters by Various Sources, 1991 -199867
,;!:, ("jji "',,, ;!",,, , ')•(/;• Jiv'lEi; i liSif:',;"1:;,!
iiMJili ill iJ iliillhousai
Wear*'',,,
IP n '• iili', 'i ,'" i'
1991
1992
1993
1994
1995
1996
1997
1998
: ^^sj^
100,243
78.0%
76,580
88.3%
114,608
89.0%
98,532
85.0%
96,429
80.5%
91,803
82.4%
85,412
81.2%
92,959
88.8%
^^Authorities: '
24,401
19.0%
6,460
'7.4%
10,126
7.9%
13,085
11.3%
19,419
16.2%
18,262
13.7%
15,888
15.1%
7,970
7.6%
Other
... ,,,.,,,.•' i v*..,,. ,: '.;.,, . .^H
3,906
3.0%
3,734
4.3%
4,020
3.1%
4,247
3.7%
3,935
3.3%
4,345
3.9%
3,935
3.7%
3,795
3.6%
128,550
100.0%
86,774
100.0%
128,754
100.0%
115,864
100.0%
119,783
100.0%
111,410
100.0%
105,235
100.0%
104,724
100.0%
Source: American Association of Port Authorities, 1995.
7 Figures for the years 1991 to 1993 are actual amounts, while figures for years beyond 1993 are projections.
Figures are from a survey of sources. Not all sources responded to the survey, so the figures do not represent total
quantities for the nation. Responses from the Army Corps of Engineers represent national figures, but only 46 (61
percent) of U.S. member ports responded. Quantities obtained from the survey seem to be approximately one
third of actual quantities for each source, and USAGE numbers are low compared with other estimates.
162
-------
The Indicators: Maritime
0)
•o
Quantities Dredged from
U.S. Waters
W
O
la
•3
O
H—
0
V)
c
o
150 -j
100 -
50 -
0 -
•* f^Km,
- \y ^^^*B*
•^P"
i i
i i
Reported
Projected
1990 1995 2000
Source: American Association of Port Authorities, 1995.
QUANTIFIED ACTIVITY INDICATORS
* Th'e U.S. Army Corps of Engineers maintains approximately 25,000 miles of commercially
navigable channels, serving 400 ports, including 130 of the nation's 150 largest cities (U S
EPA, 1989b).
OTHER QUANTIFIED DATA AND LOCAL EXAMPLES
4 One study revealed that the immediate effects of dredging on a soft-bottom habitat were a 40
percent loss in number of species, 65 percent loss in density of macroinfauna, and a 90
percent loss in biomass of invertebrates (Canter, 1985).
* . In a study of the Wild Rice Creek Watershed in North and South Dakota, wetland drainage
rates were 5.3 times higher in channeled sections than those in unchanneled sections (Canter
1985). . . - '
DESCRIPTION OF IMPACT
Navigation improvements have the potential to cause a variety of harmful environmental impacts.
.Dredging is the primary infrastructure activity undertaken to improve navigation for water-borne
transportation. In addition, engineering projects,'such as stream channelization, have environmental
impacts. While channelization projects are typically not undertaken to improve transportation, they
may reduce flooding and prevent changes in a river's course, which affects inland transport. Other
infrastructure improvements may influence the amount of recreational boating.
Two aspects of dredging can cause environmental damage: (1) disturbance and removal of bottom
material and (2) disposal of dredged material. The second of these impacts is discussed in the next
section. Dredging, which involves the mechanical displacement Of sediments for the purpose of
creating, maintaining, or extending ports and navigational waterways, necessarily disrupts bottom
habitats (U.S. EPA, 1989b). One study revealed that the immediate effects of dredging on benthic and
.other animal communities can be substantial, although dredged areas recover if left undisturbed
(Canter, 1985). Maintenance dredging, however, which entails dredging a particular channel -
periodically to sustain a prescribed depth, can prohibit recovery. Dredging can also alter natural water
163
-------
Indicators of the Environmental Impacts of Transportation
circulation patterns, which can affect ecosystems in a variety of ways, such as through increased or
decreased salinity (Canter, 1985).
Engineering projects, such as stream channelization, result in changes in water flow patterns, often
with serious side effects, such as increases in sediment deposits (Griffin, 1991). It should be noted
that many channelization and dam projects are not undertaken for the purpose of navigation
improvement. Channelization projects can have negative impacts on water quality, aquatic
ecosystems, and terrestrial ecosystems. Some possible water quality problems associated with
channelization are altered turbidity and pH values, conductivity, dissolved oxygen levels, and
temperatures in streams. Fluvial ecosystems can experience decreased habitat variability, reduced
invertebrate populations, and decreased fish populations due to channelization. Within terrestrial
ecosystems, channelization projects can cause reduced or altered riparian habitat (any habitat located
on the bank of a natural body of water), drained wetlands, decreased bird and mammal populations,
loss of ground cover, and raised water tables (with associated detrimental effect on some tree species)
(Canter, 1985).
It should also be noted that navigation improvements may spur additional maritime travel, which
would have environmental impacts (see the section on travel impacts below). This indirect effect of
navigation improvements is not considered here.
CAUSAL FACTORS
4 Demand for new or expanded waterways
• Need for maintenance dredging
* Type of dredge and other construction equipment used
4 Successful implementation of various efforts to avoid or mitigate impacts
4 Size of vessels using ports
4 Species/habitats in channels
HABITAT DISRUPTION AND CONTAMINATION FROM DISPOSAL OF DREDGED MATERIAL
PRESENTATION OF INDICATORS
QUANTIFIED OtlTCOM&'RESULTS INDICATORS
4 Nine states reported that disposal of dredged material was a source of direct wetlands losses
in 1992 (U.S. EPA, 1994b).
4 In a test of the effects of contaminated dredged sediments on eleven species of benthic
macroinvertebrates by EPA and the Army Corps of Engineers, one amphipod species
experienced acute mortality. Other species experienced milder impairments, such as limited
burrowing activity and tube building. Such impairments can impact the abundance of a
species (U.S. EPA, 1989b). Nationwide impacts have not been estimated.
QUAWflflEO OUJPUT/WDfCATOflS
4 Dredged material is the largest source of waste disposal in U.S. coastal waters (U.S. EPA,
1989b).
164
-------
The Indicators: Maritime
Estimates of the annual amount of U.S. dredged material disposed in the ocean range from 75
million to 180 million wet metric tons (U.S. EPA, 1989b). The table below presents
additional information on quantities of dredged materials disposed in various places.
Disposal/Use of Dredged Material from U.S. Waters by Various Dredgers, 199368
*-"' /" '^JiV*,V* -A vw-v\ * Vj^onsaaid^Cubic Yards (Percentage of All
*"" ^-""- o-~ >^ -~> > - < Slaierial)
- * - v , /> ^£ -^i ^ * - ,
'Disposal/Use x «„,'"*"
Ocean Disposal
Coastal Waters Disposal
Great Lakes Disposal
Confined Upland Disposal
Other Disposal
~
Construct. Aggregate
Beach Nourishment
Land Creation
Wetland Creation
Wetland Restoration
Other Beneficial
All Use and Disposal
• U.S. Array s.
^'"C0i:ps
21,817
23.9%
1,207
1.3%
' 0
o.'o%
23,409
25.7%
500
0.5%
300
0.3%
3,689
4.0%
6,500
7.1%
31,528
34.6%
0
0.0%
2,154
' 2.4%
91,104
100.0%
~ . Port "
Autliorities
1,092 '
3.0%
534
1.5%
.0,
0.0%
6,794
18.8%
750
2.1%
200
0.6%
3,565
9.9%
16,418
45.4%
1,700
4.7% '
100
0.3%
5,000
13.8%
36,153 .
100.0%
Oflier
Dredgers
7,535
29.4%
93
0.4% .
0
0.0%
2,817
11.0%
7,000
27.3%
76
0.3%
100
0.4%
0 ,
0.0%
8,000
31.2%
. 0
0.0%
0
0.0%
25,621
100.0%
AH ,,
8 Dredgers
30,444
19.9%
1,834
1.2%
0
0.0%
• 33,020
21.6%
'8,250
5.4%
576
0.%
7,354
• 4.8%
. 22,918
15.0%
41,228
27.0%
100
0.1%
7,154
4.7%
152,878
100.0%
Source: American Association of Port Authorities, 1995.
68
Figures are from a survey of sources. Not all sources responded to the survey, so the figures do not represent'
total quantities for the nation. Responses from the Army Corps of Engineers represent national figures, but only
46 (61 percent) of U.S. member ports responded. Quantities obtained from the survey seem to be low compared
with aggregate estimates from other sources.
165
-------
Indicators of the Environmental Impacts of Transportation
Disposal Locations/ Uses of Dredged Material - 1993
Other
beneficial use
Ocean
disposal
Wetland
creation
Beach
nourishment
Land creation
Coastal waters
and Great Lakes
disposal
Confined upland
disposal
. Other
Construction disposal
aggregate
Source: American Association of Port Authorities, 1995.
The percentage of dredged material in the U.S. that is contaminated enough to require special
handling is less than 10 percent and possibly lower than 5 percent, although past estimates
have ranged as high as 30 percent (Cullinane et al., 1990). Certain ports, however, have
reported much higher percentages. For example, MASSPORT reported that a third of its
dredged material was contaminated, and the ports of both Jacksonville and San Diego
reported that half of their material was contaminated in 1993 (American Association of Port
Authorities, 1995).
The U.S. Army Corps of Engineers considers approximately 3 percent of its dredged material
to be highly contaminated and 30 percent to be moderately contaminated (U.S. EPA, 1989b).
Concentrations of lead, mercury, and other metals in dredged material have been found to be
much higher than naturally occurring levels in some cases (see table).
Chemical Characteristics of Dredged Material Compared with
Average Material from the Earth's Crust
Constituent
iiSsissJKpjfefe-i !_,__ „„
Iron
Manganese
Zinc
Copper
Nickel
Chromium
Lead
Cadmium
Mercury
S^SyiztSeSc Organics
Chlorinated pesticides
Polychlorinated biphenyls
Dredged Materials
Stoles per kg
6.02 - 0.90
(0.4 - 10) x 10'3
(0.5 - 8) x lO'3
(0.8 - 9,400) x 10"6
(0.2 - 2.6) x 10'3
(0.02 - 3.8) x 10'3
(5 - 1,900) x 10'6
(0.4-600)xlO-6
(1 - 10) x 10"6
mgperlcg . •• ••>•"•
0-10
0-10
Average Crustal
Materials
Motes per kg „
' 0.61 -- 1.03
(12 - 18) x 10'3
(0.92~1.26)xlO'3
(460 - 1,090) x 1Q-6
(0.62 - 1.69) x 10'3
(0.92 - 1.92) x 10'3
(48 - 77) x ID'6
(0.89--1.6)xlO-6
(0.149 - 0.398) x 10"6
Source: U.S. EPA, 1989b.
166
-------
The Indicators: Maritime
OTHER INDICATORS AND LOCAL EXAMPLES
' * Within the New York Bight, dredged material, sewage sludge, and acid and chemical wastes
(the total of ocean-dumped wastes) contribute 15,000 tons/day of suspended solids, 3,200
tons/day of chemical oxygen demand, 660 tons/day of total organic carbon, 50 tons/day of -
ammonia nitrogen, 2 tons/day of cadmium, 0.026 tons/day of mercury, 5.6 tons/day of lead,
and 9.3 tons/day of zinc. Dredged material is the largest contributor of these pollutants, with
a low of approximately 50 percent of the total mercury contribution and a high of nearly 100
percent of the cadmium contribution (U.S. EPA, 1989b).
* Repeated disposal of dredged material at a site in Central Long Island Sound has resulted in
the formation of several mounds 1 to 3 meters in height with radii of up to 400 meters (U.S.
EPA, 1989b). '.
DESCRIPTION OF IMPACT
Dredging (and other navigation improvements) results in accumulation of extensive amounts of
material from the bottoms of bodies of water. Some of this material is used for beneficial purposes,
such as construction, beach nourishment, land creation, wetland'creation, and wetland restoration.
The rest ,qf this material, especially contaminated sediments, must be disposed.
Disposal of dredged material has the potential to cause far-reaching environmental impacts. There are
two major methods of disposal: (1) disposal in open water, and (2) disp'osal on land. Disposal in open
water can alter bottom habitats, decrease water quality, and befoul marine organisms. Repeated
disposal at a site can form mounds in bottom habitats, because most material sits where it is dumped.
Disposal of dredged material in open waters can affect water quality by physical means, such as
increasing turbidity, or chemical means, such as raising pollutant concentrations. Open water disposal
can harm marine organisms in a number of ways. Benthic organisms can be killed simply by physical
burial under dredged material. A more widespread effect of disposal on marine fauna, however, is
uptake of toxics. Contaminants may impact the benthic community even if dredged material is capped,
and larger animals may ingest contaminants either directly or indirectly through feeding on smaller
animals (U.S. EPA, 1989b).
Disposal of dredged material on land can be beneficial or detrimental, depending for the most part on
the quality cf the material. Clean material can be used for beneficial projects. Disposal of
contaminated dredged material on land is highly controversial for many reasons, including its high
cost and the possibility of pollution. Contaminants can potentially escape from upland containment
facilities -juid enter groundwater aquifers or surface waters (U.S. EPA, 1989b).
* = '
CAUSAL FACTORS
* Level of construction activity ,
o Quantity and types of hazardous materials in dredged material
4 Type of disposal (e.g., capped, uncapped, contained)
* Location of disposal (land, coastal waters, open ocean)
* Quantity of past dredging activity
167
-------
• ' 4
Indicators of the Environmental Impacts of Transportation
HABITAT DISRUPTION AND LAND TAKE FOR PORTS AND MARINAS
PRESENTATION OF INDICATORS
* Habitat, species, recreational, and other impacts of ports and marinas have not been
estimated at the national level.
QUW?RED OUTPUT INDICATORS
* Amount of shoreline acreage developed specifically to support maritime transportation is
unknown.
QumnemD ACTIVITY INDICATORS
* There are approximately 10,000 marinas in the U.S. (International Marina Institute, 1991
database).
* The U.S. Army Corps of Engineers maintains channels that serve 400 U.S. ports, including
130 of the nation's 150 largest cities (U.S. EPA, 1989b).
DESCRFHON OF IMPACT
Maritime transportation impinges on coastal, riparian, and other marine habitats through the taking of
land to construct and operate ports and marinas (Button, 1993). In many cases, ports and marinas
sequester and develop extensive natural areas, resulting in degraded ecosystems and loss of habitats.
It is extremely difficult to attribute a share of this impact to maritime transportation. A great deal of
coastal development is not directly related to transportation. For example, some of the development in-
coastal cities, such as New York City, is directly attributable to maritime transportation (e.g., loading
docks). Other developments, such as office buildings for managers of loading dock facilities, may or
may not be attributable to marine transportation. Determining what shoreline development is
attributable to marine transportation is difficult; determining the portion of habitat loss caused by that
development is even more difficult.
CAUSAL FACTORS
4 Number of new port facilities constructed
* Level of expansion of existing ports and marinas
* Inappropriate siting of marinas or port facilities
' *>
168
-------
The Indicators: Maritime
2. MANUFACTURE OF MARITIME VESSELS AND PARTS
A large variety of maritime vessels are manufactured. The inventory of vessels includes non-self-
propelled barges, tankers, and floats; ferries; tankers; towboats; sailing vessels; recreational boats
(primarily small pleasure craft), and large ocean-liners. The manufacture of these vessels results in
environmental impacts through the release of toxics to the air, soil, and water.
Toxic Releases
TOXIC RELEASES
PRESENTATION QF INDICATORS
QUANTIFIED OUTCOME/RESULTS INDICATORS
* No quantified data on human health impacts, such as increased incidence of cancer from
toxics, or habitat and species impacts are available.
QUANTIFIED OUTPUT INDICATORS •
4 Some 203,722 pounds (or about 102 tons) of toxic chemicals were reported released on-site
from vessel manufacturing facilities in 1994 (see table).69
69 Impacts of imported equipment and parts are not counted here. Only U.S. facilities are included here,
including the impacts pf exported equipment.
169
-------
Indicators of the Environmental Impacts of Transportation
Toxic Chemicals Released from Vessel Manufacturing Facilities (Pounds in 1994)
SIC* Industry Type
Code •
3730 Ship and boat
building and repair
On-Site Releases (Pounds)
Air Water Land Total
203,702 20 0 203,722
POTW" Off-Site
Transfer Locations
Transfer
' 0 ' 36,454
*SIC = Standard Industrial Classification
kpOTW = Publicly owned treatment works
Source: Toxic Releases Inventory, 1994
QtMtimEDAcnvnY INDICATORS
4 The number of vessels in the U.S. has increased dramatically over the past 30 years, as the
following table shows. The increase in the vessel fleet provides an indication of the amount
of vessel manufacture, but does not signify that new vessels were produced in the U.S.
Vessel Inventory, 1960-1992
Year Non-self propelled Self-propelled Recreational boats
(barges/floats) • (thousands)
1960
1970
1980
1990
1992
16,777
19,377
31,662
31,017
30,899
6,543
6,455
7,130 ,
8,216
8,311
2,450
7,400
14,600
19,500
20,300
Source: BTS, 1995.
DESCRIPTION OF IMPACT
The manufacture of ships and boats involves use of a variety of materials and chemicals. During the
manufacturing process, toxic chemicals are released from vessel manufacturing facilities into the
environment. Releases occur as on-site discharges of toxic chemicals, including emissions to the air
and discharges to water. Chemicals are transferred off-site when they are shipped to other locations.
On-site releases to air occur as either stack emissions, through confined air streams such as stacks or
vents, or fugitive emissions, including equipment leaks, evaporative losses from surface
impoundments and spills, and releases from building ventilation systems. Surface water releases may
include releases from discharge pipes as well as diffuse runoff from land, roofs, parking lots, and
other facility infrastructure.
Off-site transfers represent a movement of the chemical away from the reporting facility. Except for
off-site transfers for disposal, these quantities do not necessarily represent entry of the chemical into
the environment. Chemicals are often shipped to other locations for recycling, energy recovery, or
treatment.
The toxic releases from manufacturing facilities cause many of the same problems as releases from
vessel terminal operations. These problems include ecosystem impacts (e.g., unhealthy wildlife) and
human health effects (e.g., respiratory problems). In general, the scale of pollution from the vessel
170
-------
The Indicators: Maritime
building industry is relatively minor compared with inany other industries, such as automobile
manufacturing. .
CAUSAL FACTORS . ,
* Number of vessels built
* Amount of chemicals used per vessel .
4 , Efficiency of controls and efforts to reuse or recycle chemicals and other materials, including
pollution prevention .efforts
4 Amount of chemicals and materials transferred to other locations for recycling, energy
recovery, or treatment
4 Types of chemicals released and toxicity . ,
* Population density and extent of exposure'
4 Environmental conditions such as climate, topography, or hydrogeology affecting fate and
transport of chemicals and materials in the environment ,
171
-------
-------
The Indicators: Maritime
3. MARITIME TRAVEL
Maritime travel is responsible for a number of environmental impacts, including air pollution from
fuel consumption; habitat disruption caused by wakes and anchors; wildlife collisions; introduction of
non-native species; and releases of solid waste, sewage, and hazardous materials. Based on data
availability, statistics for both recreational vessels (primarily small pleasure craft) and non-
recreational vessels are presented. There is some disagreement about whether recreational boating
serves a transportation purpose (the movement of goods or people from one place to another);
however, data on recreational boating are presented here since recreational boats are mobile sources
that have significant impacts on the environment, and it is difficult to separate the recreational
component of any mode of transportation.
Air Pollutant Emissions
Introduction of
Non-native
Species
Hazardous
Materials
Spills
Habitat Disruption
caused by
Wakes and Anchors
AIR POLLUTANT EMISSIONS
PRESENTATION OF INDICATORS
QUANTIFIED OUTCOME/RESULTS INDICATORS
* No data are available on the health or habitat effects of emissions from water-based travel.
QUANTIFIED OUTPUT INDICATORS
4 m 1994, maritime vessel operations were responsible for the following emissions
nationwide, including recreational vessels (U.S. EPA, 1995e):
173
-------
Indicators of the Environmental Impacts of Transportation
Pollutant Quantity Emitted Percentage of total
(1994, thousand Emissions of that
short tons ) Pollutant70
Carbon Monoxide (CO)
Nitrogen Oxides (NOX)
Volatile Organic Comp. (VOCs)
Sulfur Dioxide (SO2)
Paniculate Matter (PM-10)
1,319
208
489
206
29
1.35%
0.88%
2.11%
0.98%
0.06%
4 In 1993, CO2 emissions from maritime vessel operations (including recreational boats and
international shipping vessels) accounted for approximately 34 million metric tons of carbon
equivalent (mmtCe), or 2.5 percent of total national anthropomorphic CO2 emissions
(Apogee estimate).71
4 Maritime vessels contributed to emissions of other greenhouse gases, as reported below (U.S.
EPA, 1994a):
Pollutant Quantity Emitted
(1990, thousand
metric tons)
Methane (CKO 3
Nitrous Oxide (N2O) "l
*° Percentages are based on anthropogenic emissions, except for PM-10, which includes natural emissions.
71 Estimate is based on the following methodology: transportation sector energy use by fuel type within a mode
(DOE/ELA, 1995b) was multiplied by carbon coefficients-mmtCe/quadrillion Btu-for each fuel (DOE/EIA,
1995a), then adjusted by fraction of carbon that does not oxidize during combustion (DOE/EIA, 1995a). Note
that this estimate does not account for upstream emissions, such as emissions from vessel assembly and fuel
production.
174
-------
The Indicators: Maritime
CO Emissions from Maritime Vessels
Year
1970
1980
1985
1986
1987
1988
1989
1990
1991
, 1992
1993
1994 '
Recreational
Vessels
(Thousand
Short Tons)
976
1102
1157
1167
1175
1185
1195
1207
1221
1233
1245 ,
1256
Non ,
Recreational
Vessels (TST),
14
37
' 44
47
50
56
59
58
58
60
62
63
Percentage
Total
National
Emissions
0.77%
0.98%
1.04%
1.11%
1.13%
1.07% '
1.22%
1.26%
1.31%
1.37%
1.39%
1.35%
Source: U.S. EPA, 1995e.
CO Emissions
at
I
r
o
w
T3
1400
1200
1000
800
600
400
200
- Recreational
vessels
-Non
Recreational
1970
1980
Year
1990
NOX Emissions from Maritime Vessels
Year Recreational Non " Percentage
Vessels , Recreational Total
(Thousand Vessels National
Short Tons) (TST) Emissions
1970
1980
1985
1986
1987
1988
1989
1990
1991
1992
1993
1994
16
18
19
19
19
19
19
20
' 20 '
20
20
20
40
110
131
140
• 149
165
175-
173
174
179
183
188
0.27%
0.55%
0.66%
0.71%
0.75%
. 0.78%
0.84%
• 0.84%
0.86%
0.87%
. 0.87% :
0.88%
200
NOx Emissions
Non
Recreational
Vessels
Recreational
Vessels
1970
1980 1990
Year
Source: U.S. EPA, 1995e.
175
-------
Indicators of the Environmental Impacts of Transportation
VOC Emissions from Maritime Vessels
Year Recreational Non Percentage
Vessels Recreational Total National
""i I! ' i, J''ii ' '. . , ' : , ' ' ", . ' >!, 1|. ,:: ,' ,, ( ^
(Thousand Vessels Emissions
Short Tons) (TST)
1970
1980
1985
1986
1987
1988
1989
1990
I99J
1992
1993
1994
350
395
413
416
419
422
425
429
434
438
442
446
9
25
30
32
34
38
40
39
40
41
42
43
1.17%
1.62%
1.72%
1.79%
1.83%
1.79%
1.94%
1.98%
2.07%
2.14%
2.14%
2.11%
Source: U.S. EPA, 1995e.
SO3 Emissions from Maritime Vessels
Year
1970
1980
1985
1986
1987
1988
1989
1990
1991
1992
1993
1994
(Thousand
Short Tons)
43
117
143
154
164
181
193
190
191
197
201
206
Percentage Total
National Emissions
0.14%
0.45%
0.62%
0.68%
0.74%
0.80%
0.83%
0.85%
0.87%
0.90%
0.93%
0.98%
450
400
VOC Emissions
Recreational
Vessels
Non
Recreational
Vessels
1970
1980
Year
1990
SO, Emissions
U)
I
r
o
(0
CO
(0
o
250
200
150
100
1980 1990
Year
Source: U.S. EPA, 1995e.
176
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The Indicators: Maritime
PM-10 Emissions from Maritime Vessels72
Year
(Thousand
ShortTons)
Percentage Total
National Emissions
PM Emissions
1970 ^6
1980
1985
, 1986
1987
• 1988
1989
1990
1991 •
1992
1993
1994
17
20
21
• 23
25
27
26
26
27
28 ,
29
-
0.04%
0.04%
0.05%
0.04%
0.05%
0.06%
0.05%.
0. 06%
0.07%
0.06%
30
25
20
CO
' C
,2
o .'
W 15
10
0
1970
1980
Year
'1990
Source: U.S. EPA, 1995e.
It is important to note the uncertainty regarding the values used for these output indicators. Since
actual measurement of all vessel emissions is impractical, the emissions estimates come from models,
which can produce varying estimates based on alternative methodologies and assumptions.
There is some evidence that air pollution can have a significant impact on water quality. Some portion
of atmospheric deposition may result from maritime vessel emissions, although statistics on such
pollution cannot be disaggregated to separate modes. See the section on highway air pollutant
emissions for more information on atmospheric deposition.
QUANTIFIED ACTIVITY INDICATORS
4 Refer to Appendix A for data on maritime travel.
DESCRIPTION OF IMPACT - '
Although similar pollutants are emitted from maritime vessels and motor vehicles, there are several
key differences regarding emissions: (1) maritime vessels produce a much lower total quantity of
emissions; (2) emissions from maritime vessels tend to occur over different ecosystems than those
from motor vehicles; and (3) emissions from vessels have a chemical composition different from that
of motor vehicle emissions. Lower quantities of total emissions make the effects of vessel emissions
less pronounced than those of motor vehicles. Although emissions can travel widely and cause harm
in places that are removed from the point of release, emissions from vessels are less likely to affect
humans and land-based ecosystems and structures. Emissions from vessels, however, cause somewhat
different effects, since they produce more SO2, NOX, and PM-10 and less CO and VOC per volume
emitted than motor vehicle emissions (U.S. EPA 1993g).
72
Percentage of total emissions are not reported for particulate matter prior to 1985 because of changes in total
emissions inventories; fugitive dust and wind erosion are reported only for the period 1985 to 1994.
177
-------
Indicators of the Environmental Impacts of Transportation
Air emissions from vessels affect ecological and human health in a number of ways. Pollutants in
emissions can cause respiratory and other illnesses, reduced visibility, soiling and corrosion of
materials, damage to land-based and marine plants and animals, and contribution to global warming.
While the percentage of total national emissions from vessels is minor compared with some other
sources of air pollutants, vessel emissions have the potential to cause serious local and regional
impacts. In addition, unlike auto emissions, total air emissions of pollutants from vessels are on the
rise in the U.S.
CAUSAL FACTORS
4 Number of vessel trips :
4 Emissions per volume of fuel consumed, per trip, or per distance traveled, by chemical
* Distance traveled
* Engine type, age, and emissions control technology
4 Fuel consumed (by type) affects emissions per mile
* Travel characteristics: speed, acceleration, etc. affects emissions per mile
* Climatic conditions (temperature, wind, rain, etc.) affects dispersion/dilution of pollutants
and formation of secondary pollutants
4 Population density affects number of people exposed to pollution
4 Rate of wet deposition
4 Sensitivity of local ecosystems
HABITAT DISRUPTION CAUSED BY WAKES AND ANCHORS
PRESENTATION OF INDICATORS
QuwnBH) Oy7COM©ftes«.7s INDICATORS
4 The total area of shoreline erosion caused by wakes and the amount of vegetation and coral
damaged and species affected by wakes and anchors is not known.
QUWTJRED OUTPUT INDICATORS
4 No data are available regarding the number and size of wakes in sensitive locations.
QtMWTJRHJ ACTMTYINDICATORS
4 No data have been found regarding the number of anchors dropped, the amount of traffic, or
the average size and speed of boats in sensitive locations.
DESCRIPTION OF IMPACT
Several environmental impacts are the result of wakes from large or high-speed maritime vessels and
anchoring. Wakes from large (e.g., cruise ship) or fast-moving vessels can cause erosion and
vegetative and coral damage in confined or shallow waters. Wakes can cause strong wave propagation
that is capable of eroding shorelines or stirring up bottom sediments in shallow areas. Vegetation can
be disturbed both by erosion processes and by sedimentation resulting from wakes. Sedimentation
reduces the amount of sunlight available for photosynthetic processes. Corals also are susceptible to
damage from sediments that have been suspended by the action of wakes. The impacts of wakes are
very local in nature and likely to be more pronounced in confined areas of high traffic.
178
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The Indicators: Maritime
Dropping of anchors from vessels, like wakes, can cause local habitat damage. This damage occurs
through direct physical disruptions, as anchors are dropped on habitats and sometimes dragged
through them. Anchor damage can be especially serious in highly productive but sensitive ecosystems,
such as coral reefs.
CAUSAL FACTORS - '
4 Volume of vessel traffic ;
* Size of vessels
* Speed of vessels , •
* Number of anchors dropped • '
* Sensitivity of local ecosystems to physical abuse
INTRODUCTION OF NON-NATIVE SPECIES
PRESENTATION OF INDICATORS
QUANTIFIED OUTCOME/RESULTS INDICATORS
* No data are available on the damages to ecosystems or species loss due to introduction of
nonnative species to habitats via boat. No data are available on impacts to fisheries, water
treatment facilities, or other resources.
QUANTIFIED OUTPUT INDICATORS
* Over 130 non-native species have been introduced to the Great Lakes since 1800, and nearly
a third are believed to have been carried in by ships (Council on Environmental Quality,
1993).
DESCRIPTION OF IMPACT , . .
The introduction of non-native species tp certain habitats may result in severe environmental strain or
damage to a functioning ecosystem. Non-native species may compete with native species for food
and force out existing creatures. For example, the zebra mussel, a non-native nuisance species,
probably entered the Great Lakes through discharge of ballast water from an ocean-going vessel. The
mussels could potentially disrupt the food web in the lakes by devouring microscopic plants that form
the foundation of the web. Colonies of zebra mussels also clog water intake pipes at power plants and
water treatment facilities (Council on Environmental Quality, 1993). Other non-native species may
out-compete existing species, resulting in significant alterations to the aquatic ecosystem.
CAUSAL FACTORS
f Number of foreign ships entering U.S. waterways
* - Lack of proper disposal or exchange of ballast water or other contaminated cargo
4 Lack of enforcement of ballast water management ,
179.
-------
Indicators of the Environmental Impacts of Transportation
HAZARDOUS MATERIALS INCIDENTS DURING TRANSPORT
PRESENTATION OF INDICATORS
QwmFKo OUTCOME/RESULTS IwtcATORS
* No statistics were found regarding the number of species nationwide affected by hazardous
materials incidents.
QUANTIFIED OUTPUTIWKATORS
* In 1994,5,295 incidents were reported involving oil spills in U.S. navigable waters (U S
DOT, 1996).
Oil Spills from Vessels in U.S. Navigable Waters, 1982-1994
Kill IT
">, Year
1982
1983
1984
1985
1986
1987
1988
1989
1990
1991
1992
1993
1994
Numbier of
Incidents
2,209
2,225
2,267
1,662
1,612
1,779 '
2,008
2,268
2,486
2,428
5,310
5,430
5,295
, Gallons ,
Spilled
3,778,982
2,332,256
9,011,868
4,862,911
2,835,916
2,945,770
4,386,289
12,693,817
6,437,158
730,489
665,432
1,177,157
1,276,914
Source: U.S. DOT, 1996.
Corrosive materials constituted the class of hazardous materials with the largest number of
reported incidents—17—and the largest reported quantity released—8,446.9 gallons—over
1990-1994.
180
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The Indicators: Maritime
Incidents Involving Releases of Hazardous Materials from Non-Bulk, Interstate Vessels in U.S.
Waters (Total, 1990-1994)73
j,€3ass of Hazardous, t Nuinbeif of , Quantity
r ' *" Material," „ Incidents Released
Corrosive material
Flammable
combustible liquid
Poisonous material
Nonflammable
compressed gas
Oxidizer
Radioactive material
Combustible liquid
Organic peroxide
Other
17
8
6
,3
•. 2
2
1 '
1
1
8,446.9 gal.
578.2 gal.
64.7 gal.
1.5 gal.
0.4 gal.
4.3 Ibs.
3.0 gal.
1.0 gal.
2.0 gal '
Economic
Damages ($)
276,507
, 201,925
8,250
47,880
132,412
3,000
2,300
28
200
Source: U.S. DOT, RSPA, HMIS
* Jn 1992, vessels caused 60 percent of all oil spill incidents in navigable waters of the U.S.
(Council on Environmental Quality, 1993).
4 Tanker accidents cause 10 to 15 percent of the annual input of oil into the world's oceans
. (Miller, 1990).
OTHER QUANTIFIED DATA AND LOCAL EXAMPLES
V In 1989, the grounding of the Exxon Valdez oil tanker resulted in a spill of approximately 11
million gallons of crude oil into wildlife-rich Prince William Sound. The oil slick coated and
killed more than 34,000 birds, 10,000 sea otters, and an unknown quantity of fish. The total
count of wildlife deaths from the incident is Unknown because most of the dead animals sank
and decomposed (Miller, 1990).
4 Water transportation of hazardous materials is primarily the enforcement responsibility of
the U.S. Coast Guard. Nine states have adopted the federal regulations for such
transportation, but none are actively enforcing the regulations (RSPA; National Governors'
Association). ,
DESCRIPTION OF IMPACT :
Releases of hazardous materials, especially petroleum products, from vessels are one of the most
publicized impacts of maritime transportation: Many factors determine the extent of damages caused
by petroleum spills, including type of oil spilled (crude or refined), quantity spilled, distance of
release from shore, time of year, weather conditions, water temperatures, and currents.
The data in the HMIS database do not capture releases from bulk marine vessels, which are the most likely class of vessels
to be transporting hazardous materials. Bulk marine vessels and intrastate vessels are not required to report release
information for the data base. The numbers in the table, therefore, are only a tiny fraction of actual volumes released. For
example, petroleum crude oil is classified as a flammable liquid. Comparing the data in this table with the data on oil spills
contained in the previous table reveals the magnitude of underestimation. Data in this table, therefore, only reveal the types
of wastes being released, and provide some level of insight into the relative quantities of each class of materials released.
181
-------
Indicators of the Environmental Impacts of Transportation
When an oil spill occurs, toxic hydrocarbons, such as benzene and toluene, cause immediate wildlife
deaths. Shellfish and nonmigratory fish, especially those in the larval stage, are the mpst susceptible
to these chemicals. Other chemicals form sticky, tar-like globs on the surface that adhere to marine
wildlife such as birds, otters, and seals, as well as to sand, rocks, and almost all other substances.
Many animals that come into contact with such chemicals die from drowning or loss of body heat.
Heavy components of oil that sink to the bottom of bodies of water may have the most profound
impacts on ecosystems. Such pollution can kill or damage benthic organisms and adversely affect
food webs (Miller, 1990). Studies of some oil spills have shown that it takes most species of marine
life 3 years to recover from exposure to large quantities of crude oil. Recovery times may be much
longer (10 or more years) for exposure to refined oil, especially in areas with weak currents or cold
waters (Miller, 1990). Oil pollution in the vicinity of shorelines can cause ecological harm in coastal
ecosystems.
Humans also experience health effects from oil spills. Exposure depends on how much oil washes
ashore and how much seafood is contaminated and eaten. For the most part, oil chemicals are not
biologically magnified in food webs (Miller, 1990), so seafood impacts may not be that large. Some
of the chemicals resulting from spills, however, such as benzene, are highly toxic to humans (Miller,
1990).
Ecosystems and humans also experience impacts from maritime spills of non-petroleum hazardous
waste. Such spills can lead to wildlife kills, non-swimmable and non-fishable waters, shellfish bed
closures, and human exposure through contact and food. In addition, some hazardous substance may
undergo biological amplification in food chains, causing serious damage to organisms at high trophic
levels. Human contact with non-petroleum hazardous waste spills can be greater where a hazardous
substance spill goes undetected and warnings are not given to avoid body-contact through water
recreation.
CAUSAL FACTORS
* Quantity of hazardous materials transported
* Accident or spill rate
* Type and quantity of material released
* Toxicity/hazard of materials released
* Effectiveness of cleanup efforts
* Proximity to coastal areas
* Sensitivity and location of affected ecosystems
WILDLIFE COLLISIONS
PRESENTATION OF INDICATORS .
OUTCOME/RESULTS tacarofls
Approximately one-third of known right whale fatalities are caused by human activities,
principally ship strikes in their calving and wintering grounds in the coastal waters of Florida
and Georgia (Council on Environmental Quality).
182
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The Indicators: Maritime
!
QUANTIFIED OUTPUT INDICATORS , '
4 Data on the number of collisions between maritime vessels and wildlife are not known.
QUANTIFIED ACTIVITY INDICATORS
4 Refer to Appendix A for data on maritime travel.
DESCRIPTION OF IMPACT'
Many slow-moving marine species, especially large mammals and reptiles, are often victims of
encounters with motorized vessels. Fauna can be killed or severely injured through collisions with •
propellers or hulls. Some of the most publicized and damaging U.S. incidents involve endangered
species, such a.s the West Indian manatee, the right whale, and various species of sea turtles.
Propellers are a significant source of injuries and deaths for the West Indian manatee in coastal
Florida.
CAUSAL FACTORS •
* Number of high-speed motorized vessels
* Volume of vessel traffic
* Presence and quantity of wildlife
OVERBOARD DUMPING OF SOLID WASTE
PRESENTATION OF INDICATORS
QUANTIFIED OUTCOME/RESULTS INDICATORS
* As many as 50,000 northern fur seals die annually from entanglement in plastic marine
debris, primarily fishing nets and strapping bands (National Research Council, 1995). The
amount of this debris attributable to vessels as opposed to land-based sources and other
marine sources is unknown. . .
* Cases of entanglement have been recorded for 51 of the world's 312 seabird species and 10
of the world's 75 cetacean species (National Research Council, 1995).
* Ingestion of plastic debris has been recorded for at least 108 species of seabirds and 33
species of fish.
* Impacts on human health are unavailable.
QUANTIFIED OUTPUT INDICATORS ' . '
*' Quantity of garbage disposed of at sea by vessels is unknown.
QUANTIFIED ACTIVITY INDICATORS •
+ U.S. maritime sectors generate an estimated total of 825,168 metric tons of garbage annually
(see table) .>
183
-------
Indicators of the Environmental Impacts of Transportation
74
Estimated Annual Garbage Generation by U.S. Maritime Sectors
^^;;^
'':''
«. i' •». ' 1;**" T- is is i- '! i-i isi' -ini'tei'i-' -i
Recreational Boats
Fishing Vessels
Cargo Ships
Day Boats
U.S. Navy Vessels
U.S. Coast Guard Vessels
U.S. Army Vessels
School Boats
Offshore Industry Service Vessels
Navy Combatant Surface Vessels
Passenger Cruise Ships
Research Vessels
Misc. Private Industry Vessels
7,300,000
129,000
7,800
5,200
284
2,316
580
14
1,500
360
128
125
85
. 159,900
230,500
111,700
57,623
10,262
4,058
254
358
7,665
37,812
201,830
1,779
1,427
' Nearshore
Nearshore and Offshore
Offshore
Nearshore and Offshore
Nearshore and Offshore
Nearshore and Offshore
Nearshore and Offshore
Nearshore and Offshore
Nearshore and Offshore
Offshore
Nearshore
Nearshore and Offshore
Nearshore and Offshore
Total
7,447,392
825,168
Source: National Research Council, 1995.
DESCRIPTION OF IMPACT
The three major types of shipboard solid waste are domestic garbage (e.g., galley waste and food
packaging), operational garbage (e.g., used fishing gear, fish processing materials, and items used for
onboard maintenance), and cargo-related garbage (e.g., packaging materials and dunnage) (National
Research Council, 1995). While garbage generation is substantial for U.S. maritime sectors (see the
table above), quantifying the amount of garbage dumped overboard is difficult. Maritime travel is not
the source of all marine debris. Land-based sources and stationary maritime sources, such as oil
platforms, account for some portion of marine debris. Even data on garbage generation are highly
uncertain. Other factors, such as the fact that floatable debris can travel extremely long distances and
cross international borders, also complicate statistics about vessel garbage. While these uncertainties
affect the accuracy of indicators, the impacts of debris from vessels are genuine and can be described
to some extent.
The most readily observable ecological effects of solid waste dumping from marine vessels are
entanglement, ingestion, and ghost fishing. Entanglement occurs when wildlife come into contact with
marine debris and become trapped. Affected wildlife includes mammals, turtles, birds, fish, and land
animals that inhabit coastlines. Researchers believe that substantial numbers of animals die or are
injured because of entanglement. In fact, entanglement is thought to be the cause of serious
population declines among some species. Non-deadly injuries can be serious, causing inability to
breathe, swim, feed, or raise young properly (National Research Council, 1995).
*4 This table depicts garbage generation by U.S. fleets, not overboard dumping. Some of the generated wastes,
however, arc dumped overboard. Many of the vessels generate some portion of their wastes while operating in
non-U.S. waters. Data were collected from various sources dating from 1990 to 1994. Number of vessels was
tabulated as follows: recreational boats - boats registered in coastal states or in states bordering the Great Lakes;
cargo ships - different ships of all flags calling at U.S. ports.
184
-------
The Indicators: Maritime
Ingestion refers to instances in which animals swallow debris. The most publicized cases of ingestion
involve sea turtles and cetaceans swallowing plastic waste. Ingestion of plastic and other debris can
cause immediate death or result in a number of injuries or handicaps to wildlife. While very few data
describe the extent of damage caused by ingestion, many anecdotal cases have been documented
(National Research Council, 1995).
Ghost fishing involves lost or discarded fishing gear that continues to catch finfish and shellfish. The
extent of this problem is not well specified, but some evidence suggests that some lobster, crab, and
other fisheries experience depletion due to ghost fishing. Most of the problems from ghost fishing are
caused by lost or discarded trapping devices, such as gill nets (National Research Council, 1995).
Other possible ecological effects of overboard dumping have not been researched extensively. Effects
on coral reefs, water and sediment toxicity, invertebrates, plants, bottom habitats, and other areas may
be substantial but are not well documented (National Research Council, 1995). .
In addition to ecological problems, shipboard solid wastes that are dumped overboard can cause
human health problems. These problems are most notably associated with direct human contact with
debris. Examples of this type of problem include wounds on beaches from sharp debris that washes up
on or near shore and injuries caused by contact with hazardous chemicals. Other human health ,
hazards associated with debris include diver entanglement and boat collisions and malfunctions
caused by debris. While human health impacts from overboard dumping of solid waste are possible,
data on exposure are unavailable.
CAUSAL FACTORS
4 Quantity of food, packaging, fishing equipment, and other items used on vessels
4 Difficulty in transporting garbage on boats, and ease of overboard disposal
4 Difficulty in enforcement of laws and policies
4 Perceptions of the assimilative capacity of large bodies of water
SEWAGE DUMPING
PRESENTATION OF INDICATORS
QUANTIFIED OUTCOME/RESULTS INDICATORS •
4 In 1990, pollution from boating and marinas affected 25 percent of the harvest-limited
shellfishing waters in half of the shellfish-producing states (harvest-limited waters are those
in which shellfish beds may be contaminated) (Council on Environmental Quality, 1993).
4 In a survey of nine states, the states revealed that marinas were the third largest source of
. restrictions on shellfish harvesting (behind urban runoff/storm sewers and municipal
discharges). In these states, marinas accounted for 51 total harvesting restrictions in 1992
(U.S. EPA, I994b). It is not clear whether these reported impacts are due to sewage or other
toxic releases (e.g., oils, fuel).
4 No outbreaks of shellfish-borne disease have been traced epidemiologically to discharge of
sewage from recreational boats. Reported outbreaks, however account for a small fraction of
all shellfish-borne illness (Hackney and Pierson, eds., 1994).
185
-------
Indicators of the Environmental Impacts of Transportation
* Estimates of the total amount of sewage dumped by vessels in U.S. waters ,are not readily
available.'
QtmmED ACTIVITY INDICATORS
* Some 90 to 95 percent of commercial U.S. vessels have marine sanitation devices on board.
75 to 80 percent of recreational vessels have marine sanitation devices (U.S. Coast Guard).
OnER QUANTIFIED DATA AND LOCAL EXAMPLES
* Nationwide, shellfish harvesting in waters around marinas is typically restricted during the
boating season as a precautionary measure (Hackney and Pierson, eds., 1994).
* A 1988 survey of 379 boaters in Puget Sound revealed the following problems experienced
by boaters at shoreside pump-out stations: 17 percent found pump-outs inaccessible, 8
percent encountered crowded conditions, 5.3 percent experienced unsanitary conditions, 5.3
percent viewed fees as excessive or did not know how to use facilities, 37 percent
experienced a complete lack of available pump-outs, 27.4 percent found frequently
malfunctioning pump-outs (Washington State Parks and Recreation Commission).
DESCRIPTION OF IMPACT
The popularity of recreational boating in coastal areas has spurred rapid development of marinas,
many of which are not equipped to collect and process sewage. Boaters who use these marinas often
dump sewage in the water, rather than transporting it to proper pump-out facilities. Even in cases
where marinas or ports are equipped with sewage collection facilities, many vessels are still
responsible for sewage pollution. Some vessels do not contain a marine sanitation device (boat toilet),
and, as a result, boaters sometimes dump sewage overboard. Some vessels are equipped with marine
sanitation devices that are meant to treat sewage and dump it in the water. If these devices are
functioning improperly, untreated sewage can be dumped. Fees for pump-out of sewage holds on
vessels also give boaters the incentive to dump sewage illegally.
Sewage from vessels can cause serious local impacts on water quality and human health, especially in
areas of high recreational boat use. Studies in Puget Sound, Long Island Sound, Narragansett Bay, and
Chesapeake Bay have shown that boats can be a significant source of human wastes in coastal waters,
especially where the volume of boat traffic is high and hydrologic flushing is low. The two major
impacts of sewage discharges are introduction of microbial pathogens into the environment and
reduction in dissolved oxygen levels. Waterbome bacteria and/or viruses that enter waterways from
vessel sewage discharges can cause serious ailments and diseases, such as acute gastroenteritis,
hepatitis, typhoid, and cholera (U.S. EPA, June 1991). Many marinas are located in or near shellfish-
growing areas, and sewage dumped from the boats or at marinas has the potential to contaminate
shellfish (Council on Environmental Quality, 1993). Pathways of exposure for humans include both
direct water contact and ingestion of contaminated seafood.
Vessel sewage has a high capacity for reducing dissolved oxygen in bodies of water. Although the
volume of wastewater discharged from vessels is typically small, the organic substances in the
wastewater are highly concentrated. These organics can lead to low levels of dissolved oxygen where
vessel traffic is high. (U.S. EPA, June 1991)
186
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The Indicators: Maritime
Another effect of vessel sewage occurs when treated wastewaters are discharged from vessels. These
wastewaters are treated with chemical additives, such as chlorine and formaldehyde, which are
generally toxic to marine life (U.S. EPA, June 1991). Vessel sewage that is removed from vessels at
pump-out facilities is typically transported to POTWs for treatment. Impacts of wastewater discharges
from POTWs, therefore, are partially attributable to ves.se! sewage in some cases.
CAUSAL FACTORS
* Vessel traffic, especially recreational vessel traffic in an area
4 Poor siting of marinas near shellfish beds
4 Poor flushing of marina areas
4 Difficulties enforcing marine sanitation laws
4 Lack of functional marine sanitation devices on vessels
4 Lack of pump-out facilities at marinas
4 .Inaccessibility, crowding, or malfunction of pump-out facilities at'marinas
187
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The Indicators: Maritime
4. MARITIME VESSEL MAINTENANCE AND SUPPORT
Maritime transport requires support facilities such as ports for loading and unloading cargo and
people, repair and maintenance facilities, fueling stations, and marinas. The environmental impacts of
those facilities and indicators of those impacts are discussed below.
Releases of Pollutants
during Terminal
Operations
RELEASES OF POLLUTANTS DURING TERMINAL OPERATIONS
\ '
PRESENTATION OF INDICATORS •
QUANTIFIED OUTCOME/RESULTS INDICATORS •
4 Data on water quality, habitat, and health impacts associated with maritime vessel terminal
operations are not available.
QUANTIFIED OUTPUT INDICATORS
* Marine vessel loading and unloading operations are believed to emit as many as 60 of the
189 hazardous air pollutants (HAPs) defined in the Clean Air Act Amendments, including
benzene, toluene, ethyl benzene, and xylene. Approximately 350 facilities emitted 8,000
metric tons of HAPs in 1990 (U.S. EPA, 1994e).
' . 4 One investigation reported significant increases in tributyltin levels in marina waters.
Another study reported significant uptake of lead, copper, and zinc by hard clams at .
moderately and poorly flushed marina sites (Hackney and Pierson, eds., 1994).
* Data on other wastes generated from marine vessel terminal operations have not been
estimated at the national level (see table for list of wastes generated).
189
-------
Marine Vessel Terminal Operations:
Processes and Types of Waste Possibly Generated
' • i ' Processes/Operations""
Description -m' Wastes
Air emissions from storage tanks and
open processing equipment emissions
Grit blasting and chemical stripping
Spray painting, resin application
Engine Repair
Electroplating/metal finishing
Machine shops
Equipment cleaning, area washdown
Degreasing, equipment cleaning,
chemical paint stripping, reinforced
plastic fabrication
Vessel bilge cleaning
VOC emissions
Wastewater containing blasting media,
organic paint sludges, heavy metals,
stripping chemicals, VOC emissions
Waste paints, thinners, degreasers,
solvents, resins and gelcoat, VOC
emissions
Waste turbine oil, lubricants, degreasers,
mild acids, batteries, carburetor cleaners,
VOC emissions
Cyanide solutions, heavy metal sludges,
corrosive acid, alkali solutions
Spent cutting and lube oils, scrap metal,
degreasers, VOC emissions
Wastewater containing paints, solvents,
oils, and degreasers
Resin and paint contaminated solvents,
VOC emissions
Bilge wastes (oily water)
Source: U.S. EPA, October 1991.
4- There are approximately 700 establishments involved in marine repair in the U.S. (U.S. EPA,
October 1991).75
OTHER QUANTIFIED DA TA AND LOCAL EXAMPLES
* An estimated 0.02 percent of the total volume of fertilizer shipped to/from port facilities in
Tampa Bay are lost as fugitive air emissions. These fugitive emissions deposit an estimated
291 tons per year of nitrogen and 424 tons per year of phosphorus into the bay (Tampa Bay
National Estuary Program, 1994).
DESCRIPTION OF IMPACT
Terminal operations for maritime vessels involve boat yards and ship yards. Boat yards typically
handle recreational or small commercial boats, offering services such as painting and engine repair.
Ship yards service relatively larger vessels, and often contain extensive industrial machinery.
Operations may include structural repairs, painting, engine or power plant maintenance,
electroplating, air conditioning and refrigeration service, and electrical repair (U.S. EPA, October
1991). Other terminal operations include vessel unloading and cleaning, vessel storage, and refueling.
Many of these processes use materials that are hazardous or may in turn generate hazardous waste,
vapors, or wastewater (see the table above). The actual impact of terminal activities on the
environment depends on the type and volume of operations, level of cleanliness required, type of
waste generated, and efficiency of treatment systems in place. Wastes from such facilities, however,
can often seep into waterways and damage marine environments.
w These 700 establishments consist of facilities that fall under SIC codes 3731 and 3732, including ship and boat
building and repair yards.
-------
The Indicators: Maritime
Painting, which is a common operation in marine repair yards, involves three activities that generate
wastes. The first is surface preparation, which is usually accomplished by abrasive blasting and/or
chemical stripping. Surface preparation can cause air and water pollution, as well as generate waste
material in need of disposal. Application of paints is the second activity. Most top side and interior
paints are not significantly toxic, unlike some bottom paints. These bottom paints, referred to as
antifouling paints (to describe their function in preventing barnacle or other marine life growths),
typically contain toxic pigments such as chromium, titanium dioxide, lead, or tributyltin compounds.
Topside and interior paints may emit VOCs if oil-based. The third waste-generating activity related
to vessel painting is equipment cleaning. The equipment used for painting must be cleaned after use,
sometimes with strong cleaning solvents. Wastewaters generated from this process,may contain
hazardous substances, and air pollution can result as solvents volatalize (U.S. EPA, October 1991).
Engine repair work on small boats produces the same types of wastes as auto engine repair, including
lube oils, hydraulic fluids, waste fuels, hydrocarbon solvents, and batteries. Larger ship yards produce
higher quantities of engine-related waste and may generate supplementary wastes, such as machine-
shop cutting fluids and other degreasing and cleaning solvents (U.S. EPA, October 1991).
Vessel unloading can be a source of marine pollution. Emissions at marine terminal loading
operations result from the displacement of vapors as liquids are loaded into cargo holds either directly
through open hatches or from pipe header systems which collect the vapors and vent to the
atmosphere. In May 1994, EPA proposed a marine vessel rule, which is expected to reduce emissions
of air toxics by 95 percent (U.S. EPA, 1994e). Releases of hazardous' materials or other pollutants
• can occur during loading and unloading or through dust emissions. For example, portions of fertilizer
shipments are sometimes spilled in waterways or dust from movement of fertilizer shipments enters
waterways.
Vessel cleaning is a significant generator of wastes. The most common waste is bilge waste, which is
actually generated by the vessels themselves. Bilge waste contains wastewater mixed with oil and fuel
(U.S. EPA, October 1991). - ' .
Refueling causes problems similar to those of auto refueling stations. One major difference, however,
is that spills can enter waterways directly during marine refueling. Like auto refueling, VOCs can be
emitted in vapors. Underground storage tanks used to hold vessel fuels can also leak their contents .
into waterways.
The nature of wastes and emissions generated by terminal operations makes them harmful to many
forms of life, including humans. Humans can be exposed to toxicants directly (e.g., through
swimming in polluted waters or breathing polluted air) or indirectly (e.g., through eating seafood that
has ingested toxicants). Non-toxic pollution, such as excessive nutrient loading caused by fertilizer
releases from loading docks, damages ecosystems. Such releases can cause algal blooms, which lead
to lower water quality (often by reducing the quantity of dissolved oxygen).
CAUSAL FACTORS
• 4 Number of terminals
4 Type and level of terminal operations
4 Materials used during terminal operations
4 Fugitive material collection systems in place at port facilities
4 Wastewater treatment capabilities
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The Indicators: Maritime
5. DISPOSAL OF MARITIME VESSELS AND PARTS
SCRAPPAGE OF OLD VESSELS AND DILAPIDATED PARTS
PRESENTATION OF INDICATORS -
QUANTIFIED OUTCOME/RESULTS INDICATORS . •
4 Estimates are not available on the health and environmental impacts of landfilling or other
disposal of scrapped vehicles.
QUANTIFIED OUTPUT INDICATORS ' •
4 National data on emissions from the disposal of vehicles are not available.
QUANTIFIED ACTIVITY INDICATORS • . ,
* Data on the number of vessels scrapped/recycled annually in the U.S. have not been
identified. _ ,
* The large increase in the inventory of vessels signifies that more vessels will eventually be
scrapped or recycled than in the past.
DESCRIPTION OF IMPACT
The major impact of vessel scrappage is landfilling and other means of disposal of non-recycled parts,
some of which contain toxic components (e.g., batteries). The contribution of boat scrappage to
problems associated with landfilling and hazardous waste disposal is unknown.
CAUSAL FACTORS
4 Number of vessels scrapped
4 Size of vessels •
* Use of hazardous materials in vessels
4 Disposal method/fraction disposed of properly (recycling, recovery, etc.)
4 Recovery rate of materials in scrapped vessels
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Next Steps
NEXT STEPS
j
This section describes the logical next steps in the effort to develop and utilize indicators of the
environmental impacts of transportation. This study has taken some initial steps in presenting a
framework for indicators and a comprehensive list of environmental impacts. It has also provided
quantitative data on indicators for various impacts. There are still, however, considerable gaps in the
data and analyses needed to fully implement environmental indicators in this area. Next steps are .
listed below.
COLLECT RAW DATA OR LOCAL DATA WHERE NEEDED
This report has made clear that some impacts cannot be tracked at the national level until additional
data are collected. Sensitivity to existing reporting burdens at the state and local level is important,
and some additional data collection could be conducted by researchers rather than by requiring data
submissions. Some data are available in regional or state offices but have never been aggregated at the
national level. Impacts where new data collection or aggregation would be particularly useful include
the following:
* Wetlands impacts
* Habitat fragmentation and disruption from all modes
* Hazardous materials entering the environment from incidents
4 Emissions from vehicle maintenance and repair
* Maritime terminal operation releases
4 Emissions during construction and maintenance of infrastructure
4 Leaking underground storage tank (LUST) releases attributable to transportation
* Scrappage of aircraft, marine vessels, and rail cars/locomotives
DEVELOP NEW ESTIMATES OF CERTAIN IMPACTS
National estimates of certain impacts have not been developed to date. In some cases, such estimates
could be developed without the collection of additional raw data. Existing or new models could be
applied to develop new national estimates of certain environmental impacts. In particular, new
estimates of the following impacts are in need of development:
* Emissions from road construction and paving
4 Impacts of-and quantities of emissions from aircraft at high altitudes
> Deicing runoff impacts on water quality
, * Quantities released from spills and leaks at airports
* Other runoff impacts on water, quality
* Motor vehicle scrappage (tons disposed of, by material)
* Noise exposure (updated estimates)
* Roadkill (some data collection may be needed) •
At least two types of estimates should be developed:
4 Measures of emissions, loadings, or ambient levels, and
4 Actual health or welfare risks
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Indicators oftlie Environmental Impacts of Transportation
MODEL EMISSIONS/LOADINGS/AMBIENT LEVELS/HABITAT CHANGES
For'some activities or impacts, such as runoff, nati9nal estimates of typical transportation
contributions to loadings or .ambient levels are unavailable. Some additional analysis could apply
existing models to develop national estimates, which could serve as improved indicators of these
impacts.
CALCULATE HEALTH AND WELFARE RISKS OF AMBIENT LEVELS
In some cases, transportation emissions may be known but the results of those emissions have not
been analyzed. Standard health risk assessment approaches may be used to estimate health impacts,
using fate and transport or dispersion modeling, exposure modeling, and dose-response data. Welfare
impacts may be calculated in dollar terms in some cases, based on existing estimates of dollar impacts
per unit of damage or development of such estimates with standard approaches to valuation of
environmental assets, such as hedonic pricing, for example.
DESCRIBE EFFECTIVENESS OF MITIGATION OPTIONS
Various mitigation options (noise barriers, runoff detention ponds, and wetlands mitigation efforts,
for example) have been studied to some extent. It would be useful to track the increasing effectiveness
of such efforts and the extent of their utilization in cases where more direct, accurate estimates of
actual results are difficult to obtain. In many cases, estimates of environmental impacts implicitly
assume a certain mitigation or control effectiveness anyway. Although mitigation efforts are not an
ideal subject for results-oriented indicators, it can be quite useful to compile summaries of trends in
the effectiveness and usage of mitigation options over time. For example, one might track how many
airports are following certain management practices with regard to toxic substances, or what
percentage of wetland mitigation efforts are successful.
CONSIDER IMPACTS NOT LISTED HERE
In addition to the impacts listed in this report, transportation has other impacts on the environment
that are due to supporting land-use development patterns and industries. These effects are indirect,
and often it is difficult to apportion the damage that stems from transportation versus other sources.
Environmental damage may be caused by a variety of sources:
* Gas stations, including auto repair and maintenance
* Parking facilities (lots and garages)
* Related land-use development patterns
4 Petroleum industry (transportation's share of these upstream impacts)
* Steel industry (transportation's share of these upstream impacts)
* Chemical industry (transportation's share of these upstream impacts)
A broad analysis of transportation as a whole would include the development of indicators of
environmental harm caused by these related developments and industries.
SET UP ONGOING, CONSISTENT USE OF INDICATORS
This report identifies numerous potential indicators that have not been reported or tracked
consistently to date. It recommends the development of an organized, broad initiative to report a
consistent set of indicators. This effort should take into account the various state, federal, and private
efforts to track the environmental impacts of transportation and use those data in the policy process.
At a minimum, it would be useful to assess which indicators are being quantified annually and which
196
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^ . •, Next Steps
are available only for selected years, for example, and to coordinate efforts among various
organizations developing and reporting these indicators.
REGULARLY UPDATE OUTDATED, ONE-TIME ESTIMATES
'Several of the indicators in this report have been quantified only once, or only sporadically - in
surveys or one-time modeling exercises. These estimates should be updated regularly. Examples of
such outdated or one-time estimates that require updating include the following:
4 Noise exposure < •
4- Air toxic emissions during travel
4 Runoff (typical concentrations of pollutants in runoff)
4 Use of airport deicing agents
CONDUCT POLIQY ANALYSIS
Now that this study has compiled data on environmental impacts, and as improved indicators are
developed, they should be used to improve national policy. This could entail several types" of
relatively modest studies, which could provide policy-relevant results.
COMPARE ACROSS MODES, ACROSS MEDIA, ACROSS IMPACTS
One type of policy study will involve comparisons. One obvious comparison is between modes. Past
studies have already provided such comparisons, but not on the basis of the wide range of impacts
considered here. Based on the indicators in this report, it is possible to make comparisons of total
environmental .impacts among modes of transportation. However, it is important to keep in mind that
these indicators describe total national impacts of transportation, not impacts per vehicle-mile or
passenger-mile traveled, per ton-mile of freight, or per vehicle produced. As a result, these indicators
should not be used to make-comparisons of how changes in mode of travel would affect the
environment. Appendix A provides information on the total amount of infrastructure and travel
associated with each mode. .
The various environmental media can also be compared with determine whether water or habitat •
impacts deserve more attention than they have received relative to air quality. The many impacts
could also be compared with provide a sense of whether certain important environmental effects have
not been sufficiently addressed. Such comparisons can assist in setting legislative or budgetary
priorities. , • . ,
COMPARE TO OTHER ENVIRONMENTAL ISSUES
Several years ago, EPA's "Unfinished Business" report attracted a great deal of attention by
comparing a wide range environmental issues and attempting to identify topics that still required
significant regulatory and scientific work. With this new set of environmental statistics in hand, such
a comparison would be somewhat more complete and feasible.
CONSIDER COSTS OF POLICIES
As discussed earlier in this report, indicators provide only part of the picture. They describe the
potential benefits of environmental and transportation policies, but stop short of considering the costs
of such policies. Indicators should be coupled with cost studies to provide a more complete picture of
policy and technological options and their relative desirability.
197
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Indicators of the Environmental Impacts of Transportation
PROVIDE STATE AND LOCAL TOOLS
Often, planners would like to be able to describe quickly the environmental implications of projected
increases in VMT or of shifts in highway spending, such as an increase in construction of urban roads.
One might, at first glance, view the indicators in this report as a means to develop such estimates. For
example, one might assume that the average national impact per VMT or per lane-mile is also the
local and marginal impact of added VMT. This is often not the case, however.
Ideally, further work would determine which impacts vary directly with, VMT and which vary based
on other parameters. This work would essentially consist of development of models to predict the
magnitudes of various impacts, based on inputs such as VMT, temperature, or other causal factors
such as those listed in the report. Some such models exist, such as the highway runoff predictive
model, or noise models, but they do not exist for very many of these impacts. Also, the models
typically require numerous site-specific inputs that are costly to collect. New models could be
developed, perhaps for screening purposes.
198
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Bibliography
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United States Environmental Protection Agency. Accompanying Report of the National Performance
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United States Environmental Protection Agency. Profile of the Transportation Equipment Cleaning
Industry. 1995a. .'
United States Environmental Protection Agency. Profile of the Motor Vehicle Assembly Industry.
1995b.
205
-------
Indicators of (he Environmental Impacts of Transportation
United States Environmental Protection Agency. Profile of the Petroleum Refining Industry. 1995c.
United States Environmental Protection Agency. 7993 Toxics Release Inventory. 1995d.
United States Environmental Protection Agency. National Air Pollutant Emission Trends, 1900-1994.
1995e.
United States Environmental Protection Agency. EPA's 33/50 Program Company Profile: Lockheed
Martin, Office of Pollution Prevention and Toxics, 1995f.
United States Environmental Protection Agency. Prospective Indicators for State Use in Performance
Partnership Agreements. 1995g.
United States Environmental Protection Agency. Providing Information to Decision Makers to
Protect Human Health and the Environment, Information Resources Management Strategic
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United States Environmental Protection Agency. Inventory of U.S. Greenhouse Gas Emissions and
Sinks: 1990-1993. 1994a.
United States Environmental Protection Agency. National Water Quality Inventory: 1992 Report to
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United States Environmental Protection Agency. Environmental Regulations and Technology:
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United States Environmental Protection Agency. Accompanying Report of the National Performance
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United States Environmental Protection Agency. National Air Quality and Emission Trends Report,
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United States Environmental Protection Agency. National Air Quality and Emission Trends Report,
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United States Environmental Protection Agency. Motor Vehicle Related Air Toxics Study. 1993c.
United States Environmental Protection Agency. Handbook: Urban Runoff Pollution Prevention and
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United States Environmental Protection Agency. RCRA Fact Sheet: Motor Freight
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United States Environmental Protection Agency. RCRA Fact Sheet: Vehicle Maintenance. 1993f.
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207
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Infrastructure and Travel Measures
APPENDIX A. INFRASTRUCTURE AND TRAV'gt"
MEASURES
Infrastructure and travel are useful, but not ideal, indicators of environmental damage from
transportation. These measures may be classified as activity indicators, since the extent of
infrastructure and travel activity is often a causal factor that influences the level of environmental
damage. They provide important information when more direct output and outcome indicators are not
available. However, it is important to note that environmental damage does not correspond directly
with infrastructure or activities, and that many other factors complicate an analysis. For example,
while vehicle-miles of travel (VMT) is a relevant statistic to examine when discussing vehicle
emissions, otherfactors—-such as emissions control technologies on vehicles and the amount of
congestion on roadways—influence the amount of pollution emitted per mile traveled.
The statistics presented below may be used as activity indicators to supplement the indicators
presented in the body of this report. Typically, statistics will be most relevant in combination with the
following basic categories of activities as outlined in the report:
Category described in report
Appendix section most
relevant
Example of type of data
Infrastructure construction,
maintenance, and abandonment
Infrastructure
System mileage
Vehicle and parts manufacture Infrastructure
Vehicle fleet characteristics
Vehicle travel
Vehicle maintenance and
support
Travel
Travel
Miles' of travel
Fuel consumption '
Disposal of used vehicles and Infrastructure
parts
Vehicle fleet characteristics
Data in this appendix are divided by mode into highway, railroad, aviation, and maritime
transportation.
A-l
-------
Indicators of the Environmental Impacts of Transportation
lODE:
INFRASTRUCTURE
While parking lots, garages, and other facilities, such as gas stations, repair garages, auto sales
dealerships, parts shops, and manufacturing plants could all be discussed, the focus of this discussion
is roads. Highways and roads alone constitute a significant portion of the built environment.
ROAD MILEAGE
Road mileage is at least a crude indicator of some environmental impacts, such as habitat disruption
and runoff. It provides a sense of the possible magnitude of these effects, but is not a good indicator
of VMT-related effects (e.g., air pollution or HAZMAT incidents) since vehicle travel per mile varies
by type of road, location, and over time.
«• Total national road mileage in 1993 was 3,904,721 miles. This equals about 80 road-feet per
person.
All public roads and streets in the U.S. are classified by type and use into three major functional
systems: arterials, collectors, and local roads. These major systems are further subdivided into rural
and urban areas.1
Road Mileage by Functional System Type, 1993
System
Interstate
Other Arterials
Collectors
Locals
Total
Rural Percentage
Mileage
32,652 0.84
234,129 6.00
715,036 18.31
2,119,826 54.29
3,101,643 79.43
Urban Percentage
Mileage
12,878 0.33
147,514 3.78
85,378 2.19
557,308 14.27
803,078 20.57
Total Percentage
Mileage ;
45,530 1.17
381,643 • 9.78
800,414 20.50
2,677,134 68.56
3,904,721 100.00
Source: U.S. DOT, FHWA, 1994c.
1 Function types are defined as follows: Arterial (including the Interstate and other freeways) - The
highest classification of roads and streets, these provide the highest level of mobility, at the highest
speed, for long uninterrupted distances. Collector - These provide a lower level of mobility than
arterials at lower speeds and for a shorter distance. Collectors connect local roads with arterials and
provide some access to abutting land. Local - The lowest classification of roads, these provide a high
level of access to abutting land, but limited mobility.
A-2
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Infrastructure and Travel Measures
Mileage by Function System
Mileage by Urban/Rural Location
Interstate
45,530 Other Arterials
1.2% 381,643 .
9.8%
Locals
2,677,134
• 68.6%
Urban Mileage
803,078
21%
Collectors
800,414
20.5%
Rural Mileage
3,101,643
79%
For all 391 urbanized areas in the United States (defined as an area with 50,000 or more persons that
at a minimum, encompasses the land area delineated by the Bureau of the Census):
'4 Total roadway mileage is 639,045 miles (out of 803,078 miles on all urban roads).
Average miles of roadway per 1,000 persons is 3.8.
Total freeway mileage is 18,759 miles. . -
Average percentage of total mileage serving as freeways is 2.9 percent (compared with'U.S.
average of interstates as 1.2 percent of total mileage).
4 • Total estimated freeway lane mileage is ,96,657-miles.
However, the amount of roadway mileage per person varies significantly among urbanized areas.
Dallas and Atlanta each have over twice as many roadway miles per person as New York or Los
Angeles. ~ .
•
•
•
A-3
-------
Indicators of the Environmental Impacts of Transportation
Average Miles of Roadway per 1,000 persons in Selected Urbanized Areas
i Seattle
Mmeapoiis
St. Paul
4.7
SanFranci
Oakland
2.4
LosAngefes
2.1
Chicago
3-0 Washington
2.6
Atlanta
5.1
Boston
3.0
New York
2.2
Miami
3.2
Source: U.S. DOT, FHWA, 1994c.
LANEMILES
Lane miles provide a better indicator of environmental impact than road miles since the average
number of lanes varies by type of road. Interstate and other arterial roads tend to have more lanes
than local roads.
* In 1993, there were 8.1 million lane-miles of highways in the nation (U.S. DOT, 1995a). This
equals 166 lane-feet per person.
Lane-Miles by Functional System Type, 1993
Lane-Miles
Percent
Rural
Interstate
Other Arterial
Collector
Local
Subtotal Rural
129,600
518,400
1,425,600
4,228,200
6,309,900
1.6
6.4
17.6
52.2
77.9
• Urban
Interstate
Other Arterial
Collector
Local
Subtotal Urban
Total Highway
Source:
72,900
437,400
178,200
1,109,700
1,790,100
8,100,000
U.S. DOT, 1995a.
0.9
5.4
2.2
13.7
22.1
. ,.. 100
A-4
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Infrastructure and Travel Measures
AMOUNT OF PAVEMENT
The amount of pavement is a crude indicator related to runoff and particulate matter, especially road
dust. In addition, pavement affects travel speeds and, as a result, has some effect on. emissions.
Habitat disruption and runoff may be smaller problems on unpaved roads since less impervious
surfaces, culverts, and drainage systems are involved. However, unpaved roads may have significant
erosion or other drainage and runoff impacts. In addition, unpaved roads have a much higher rate of
emissions of fugitive dust per VMT than paved roads. '
* In 1993, about 58.2 percent of all roads in the U.S. were paved.
This is an increase from 51.9 percent in 1983,46.3 percent in 1973, 37.8 percent in 1963, and only
27.3 percent in 1953 (U.S. DOT, FHWA, 1995e). Essentially all of the unpaved mileage is on lightly
traveled rural roads
> In 1993, over 95 percent of roads in urban areas were paved. However, over half of all rural
road mileage was unpaved.
Road Type ,
Total Rural
Percent, Rural
Total Urban
Percent, Urban
TOTAL U.S.
' Percent, Total
Unpaved
1,594,579
51.4
38,917
4.8
1,633,496
41.8
Paved
1,507,064
48.6
: 764,161 •
95.2
2,271,225
58.2
TOTAL
3,101,643
100.0
803,078
. 100.0
3,904,721 '
100.0
Source: U.S. DOT, FHWA, 1994c.
3,500,000
3,000,000
g 2,500,000
o»
"g 2,000,000
"5 1 ,500,000
-------
Indicators of the Environmental Impacts of Transportation
HIGHWAY VEHICLES
The number of vehicles provides some insight into the environmental effects of vehicle manufacture
and disposal and partially explains the rise in VMT by type of vehicle.
4 There are 194.06 million registered motor vehicles in the U.S.
* There are 146,314,296 automobiles, 654,432 buses, and 47,094,754 trucks registered in the
U.S. (U.S. DOT, FHWA, 1994c). Almost three fourths of all registered vehicles are
automobiles.
Vehicles Registered, 1993
Type of Vehicle
Passenger cars
Motorcycles
Buses
1 2-axle 4-tire trucks
(light duty)
Other single-unit
trucks
Combination trucks
All motor vehicles
Number of
. . Registered Motor :....
Vehicles, 1993
146,314,296
3,977,856
654,432
40,902,865
4,465,692
1,726,197
198,041,338
Source: U.S. DOT, FHWA, 1994c.
*• In 1993, new sales of domestically produced vehicles totaled approximately 6.73 million
automobiles and 5.29 million trucks (U.S. DOE, 1994a).
New Sales of Vehicles in the U.S., 1993
Type of Vehicle
Automobiles
Motorcycles
Recreational vehicles
Trucks
Domestic Import
(thousands) •(thousands) ft
6,734
243
429
5,287
1,783
245
0
394
Total
8,518
488
429
5,681
Source: U.S. DOE,1994a.
TRAVEL
VEHICLE MILES TRAVELED (VMT)
VMT is a common measure of travel, chosen for inclusion here because it is a rough but easy to
measure and readily understood indicator of several environmental impacts. All else being equal, an
increase in VMT suggests a rise in certain impacts, such as air pollution and perhaps noise". Factors
such as technology, congestion, and population density also affect emissions per mile or total impacts
for a given level of VMT. These other factors vary over time and between locations, making VMT a
somewhat limited indicator. In addition, some impacts do not vary with VMT in a simple linear
manner. For example, a 10 percent increase in VMT may not cause a 10 percent increase in hazardous
materials incidents. Similarly, a 10 percent reduction in VMT might cause a negligible reduction in
ozone for some cities.
A-6
-------
Infrastructure and Travel Measures
VMT BY ROAD TYPE
The level of travel by functional system does not correspond proportionately to the number of miles
or lane-miles of roadway. Interstate highways contain a disproportionately high share of total vehicle
travel. For example, although rural interstates make up only 1.6 percent of lane-miles, and 0.8 percent
of road miles, they carry 9.1 percent of all vehicle miles. Urban interstates make up only 0.9 percent
of lane-miles and 0.3 percent of road miles but carry 13.8 percent of all vehicle miles, thus carrying
15 times as many vehicles per lane mile as the national average. Although urban roads only
constitute 22.1 percent of lane-miles and 20.6 percent of road miles, they carry 61.4 percent of all
vehicle traffic, as the following table shows:
Percent Highway Miles, Lane-Miles, and Vehicle-Maes Traveled, 1993
'
Mfles
Lane-Miles
VMT
Rural •'
Interstate
Other Arterial
Collector
Local
Subtotal
0.8
6.0
18.3
• 54.3
79.4
1.6
6.4 .
17.6 ,
, 52.2
77.9
9.1
15.2
9.9
4.5
38.6
Urban.
Interstate
Other Arterial
Collector
Local
Subtotal
Total Highway
0.3
3.8
2.2
14.3
20.6
100.0
0.9
5.4
2.2
13.7
•22.1
- 100.0
13.8
33.7
5.3
8.6
61.4
100.0;
Source: U.S. DOT, FHWA, 1994c.
The following diagram visually depicts the relative size of VMT on various road types in comparison
with lane-miles and road-miles:
A-7
-------
Indicators of the Environmental Impacts of Transportation
-
o
O
i1
1
I Urban Interstate
H Urban Other Arterial
Q Urban Collector
O Urban Local
• Rural Interstate
B Rural Other Arterial
H Rural Collector
Q Rural Local
Miles Lane-Miles VMT
INCREASE IN VMT
The amount of road travel in the nation has increased by roughly one third over the past 10 years, with
the most rapid growth in urban areas and on interstate highways. The amount of vehicle travel
increased by nearly 50 percent on urban interstates from 1983 to 1993.
Highway Vehicle Miles of Travel (millions of miles)
Highways Type: Increase in annual Percentage Increase Average annual
~ ! : ;'•. •!''•"," ;'":VMT, 19S3-93 annualyMT,l?i83- percentage%crease,
(millions of miles) 93 ; ^ 1983-93
Rural
Interstate
Other Arterial
Collector
Local
Subtotal Rural
60,278
61,466
45,015
16,329
183,088
41.6
. 22.5
22.4
20.0
26.1
3.5
2.1
2.0
1.8
2.3
Urban
Interstate
Other Arterial
Collector
Local
Subtotal Urban
All Roads
94,176
177,047
20,679
48,118
340,020
523,108
49.3
33.4
23.9
34.3
35.8
31.7
4.1
2.9
2.2
3.0
3.1
2.8
Source: U.S. DOT, FHWA, 1994c.
As the following table shows, the rate of VMT growth has slowed somewhat in recent years.
A-8
-------
Infrastructure and Travel Measures
VMT Growth Rates, 1980-95
Time Period
1980-85
Annualized Rate of
-Light-Daly VMT Growth
. . 3.1%
1985-90
3.9%
1990-95 (estimate)
2.4%
Apogee estimate, computed 'from U.S. DOT, FHWA, 1994c., and annual editions, 1980-1992
Measures of congestion are another relevant group of statistics for understanding environmental
impacts. Congestion can increase emissions of certain air pollutants per vehicle mile traveled, and is
also a key factor driving construction of additional highway capacity, which further affects the
environment.
Highway travel has increased at a faster rate than the capacity of the highway system.
• Travel per lane-mile increased by over 28 percent on urban interstate highways, and by nearly 27
percent on other urban principlal arterials over the 10 years from 1983 to 1993.
• On a per-lane-mile basis, the higher functional systems carried the most travel per lane-mile, with
urban interstate highways carrying the most travel per lane-mile in 1993, with 12,520 annual'
average daily traffic per lane-mile. ,
Highways Type:
1983
1993 Percentage
Increase
Rural
Interstate
Other Principal Arterial
Minor Arterial
Major Collector
Minor Collector
Local
3,000
1,900
1,180
500
210
50
4,310
2,310
1,410 '
560
240
70
44
22
19
12
14
40
Urban
Interstate
Other Freeway and Expressway
Other Principal Arterial
Minor Arterial
Collector
Local
9.810
7,720
4,640
3,000
1,550
420
12,520
9,770
5,540
3,490
1,830
490
28
27
19
16
18
17
I'-. '- •v,v,*3^M*i»dB^r^^i^u,:rv,;V--i:A-:?,i:-!»0 ~ ' ^?&M:^< 4g£
Source: U.S. DOT, 1995a.
VMT PER CAPITA •
VMT per capita is a useful statistic because it varies by location, suggesting that certain
characteristics of areas, such- as population density, or public policies, such as provision of transit
services, might reduce VMT, and thus reduce environmental impacts.
«• For all 391 urbanized areas in the United States, the average daily vehicle miles traveled
(DVMT) per capita was 20.7 in 1993 (U.S. DOT, FHWA, 1994c).
A-9
-------
Indicators of the Environmental Impacts of Transportation
However, travel per capita varies significantly between metro areas. New York has only 14.5 miles
traveled daily per person on roads, whereas Atlanta has an average 33.7 miles traveled daily per
person on roads. The average resident of the Atlanta metro area travels over twice as many miles
daily in a vehicle as the typical New Yorker.
Dafly Vehicle Miles Traveled (P VMT) per Capita, Various Cities
SanFi
Oakland
20.5
Boston
18.9
New York
14.5
Los Angeles
21.3
Miami
18.7
Source: U.S. DOT, FHWA, 1994c.
VMT BY VEHICLE TYPE:
Examining VMT by vehicle type provides some information that helps explain the underlying air
pollutant emissions. Passenger cars dominate travel; trucks tend to be less fuel efficient and emit
more emissions per mile. Buses constitute a very limited percentage of total vehicle travel, although
they carry more passengers per mile than autos.
Miles of Travel by Vehicle Type, 1993
Type of Vehicle Miles Traveled Percentage of Total
(millions of vehicle Miles Traveled
•i", -, „''.; <•-:••<::•• : ,.>.••.:-.•:•'• ...-.: .:tt •*{;.•!.;•.••.'-• ••
. , ,. ; ,. , :;,"., • :, miles) ; • . . ••. , .:•-;•.-.
Passenger cars
Motorcycles
Buses
2-axle 4-tire trucks
(light duty)
Other single-unit
trucks
Combination trucks
All motor vehicles
' 1,623,972
9,889
6,121 •
-497,201
56,693
102,709
2,296,585
70.7
0.4
0.3
21.6
2.5
4.5
100.0
Source: U.S. DOT, FHWA, 1994c.
Travel by light-duty trucks has been increasing significantly faster than travel by automobiles since
1980.
A-10
-------
Infrastructure and Travel Measures
From 1980 to 1993, auto travel increased by 45.6 percent while light-duty truck travel
increased by 70.9 percent.
Increase in Vehicle Miles Traveled, 1980-1993
&
CD
D_
Cars
Light-duty
Trucks
Source: U.S. DOT, FHWA, 1995d and annual editions
PERSON MILES TRAVELED (PMT) BY VEHICLE TYPE
Person miles traveled provides a sense of some of the benefits gained from travel, in terms of the
number of people served. Buses provide more service per VMT than cars, with about 21 people per
vehicle, in comparison with 1.7 people per average car.
Person Miles of Travel by Vehicle Type, 1993
Typeof Vehicle Person Miles Average Vehicle
' ' ' ' , , TraYeIetT(infllions of Occupancy -
- ' ' ' miles) -"
Passenger cars
' Motorcycles
Buses
2-axle 4-tire trucks
(light duty)
Other single-unit
trucks
Combination trucks
All motor vehicles
2,825,711
10,878
129,765
750,774
56,693
102,709
3,876,530
1.74
1.10
21.20
1.51
1.46
1.00
1.69
Source: U.S. DOT, FHWA, 1994c.
FUEL CONSUMED
Fuel consumption is a crude but easy to measure indicator of environmental damage. It is relevant to
air emissions, potential spills during storage and transport, and environmental impacts during
extraction and refining. Fossil fuels also constitute a non-renewable resource.
A-ll
-------
Indicatory of the Environmental Impacts of Transportation
* In 1993, motor vehicles consumed 137.194 billion gallons of fuel, up from 132.888 billion
gallons in 1992 ( U.S. DOT, FHWA, 1994c).
Fuel Consumption by Vehicle Type
Type of Vehicle
Passenger cars
Motorcycles
Buses
2-axle 4-tire trucks (light
duty)
Other single-unit trucks
Combination trucks
All motor vehicles
Fuel Consumed, 1993 Fuel Efficiency (Average miles per
(thousands of gallons) . - gallon), 1993
75,058,655
21.64
197,780
50.00
946,878
6.46
34,806,524
14.28
7,667,354
7.39
18,517,044
5.55
137,194,235
16.74
Source: U.S. DOT, FHWA, 1994c.
A-I2
-------
Infrastructure and Travel Measures
INFRASTRUCTURE
MILEAGE
Miles of railway track provide a crude indicator of the extent of habitat destruction from rail facilities.
* There were a total of 177,000 miles of railway track in 1993.2
Type of Railroad MBes of Track
Owned and Operated3
, Freight
Class I Railroads
Regional Operators
Local Operators
Passenger
Amtrak4
Heavy Rail
Light Rail
i Commuter Rail
Total
123,723
21,581
23,645
775
1,744
687
4,830
177,000
Source: AAR, 1993; Amtrak, 1994; U.S. DOT, 1994
CONSTRUCTION
4 Miles of new track constructed, 1993: 82 miles (ICC, 1993)
* Tons of track laid by Class I railroads, 1993: 441,381 tons (AAR, 1993)5
* Cross ties laid by Class I railroads, 1993: 13,223,000 (AAR, 1993)
FACILITIES
4 Rail-truck intermodal terminals (number active), 1994: 360 (300) (FRA, 1995)
4 Stations served by Amtrak, 1994: 540 (Amtrak, 1994)
4 Heavy rail transit stations, 1990: 911 (U.S. DOT, 1994)
4 Commuter rail stations, 1990: 958 (U.S. DOT, 1994)
4 Rail service facilities, 1990: 905 '
2 Freight: AAR, 1993; Amtrak: Amtrak, 1994; Transit: U.S. DOT, 1994
3 Transit rail (heavy, light, commuter) figures from 1990
4 The Amtrak system encompasses 25,000 miles of track, but only 775 miles are owned by Amtrak. Most of the
track in the Amtrak system is owned and operated by freight rail companies.
5 Although Class I railroad systems comprise only 2 percent of the number of railroads in the U.S., they account
for 73 percent of the mileage operated, 89 percent of the employees, and 91 percent of the freight revenue.
6 Transit rail: U.S. DOT, 1994; Freight Tank Cleaning: EPA/Office of Water as cited in EPA, 1995.
A-13
-------
Indicators of the Environmental Impacts of Transportation
Rail Service Facilities, 1990
Type of Service Number of
. Facilities
Rail Tank Car Cleaning 809
Heavy Rail Maintenance 43
Light Rail Maintenance 18
Commuter Rail Maintenance 35
Total 905
Source: EPA, 1995; U.S. DOT, 1994
TRANSIT RAIL SYSTEMS
The number and size of rail systems provides an indicator of the extent of environmental damage, and
the concentration of damage in various geographic areas.
Transit rail systems are concentrated in a small number of large metropolitan areas.
4 Total number of transit agencies operating passenger rail systems: 50
Type of Rail Service Number of transit authorities
: :,:, • i :-.- "; :•:!.••.••:..'., •y.v^--^-vV::i ^operating service
Heavy Rail , 14
Light Rail 20
Commuter Rail 16
Total 50
S9urce: APTA, 1994.
Among U.S. transit systems, the New York City metropolitan area dominates in terms of facilities,
with the world's largest subway fleet of 5,951 cars and 469 stations.
The New York City Transit Authority's subway system consists of the following (Metropolitan
Transportation Authority, 1994):
4 The world's largest subway fleet of 5,951 passenger cars, or 58 percent of all rapid transit
vehicles nationwide.
4 469 stations, or 51 percent of all subway stations nationwide.
4 842 miles of track, including 186 miles in transit yards, shops, and storage areas.
4 10,900 signals and 2,700 miles of cable.
VEHICLES IN OPERATION
The number of vehicles in operation provides some insight into the environmental effects of vehicle
maintenance and disposal.
A-14
-------
Infrastructure and Travel Measures
* 4 Freight cars in the active fleet, 1993: 1,173,132 (AAR, 1993)7
4 Locomotives (all diesel) in the active freight fleet, Class I, 1993: 18,161 (AAR, 1994)
* Locomotives in Amtrak fleet, 1994: 352 (287 diesel, 65 electric) (Amtrak, 1994)
4 Passenger cars in Amtrak fleet, 1994: 1,852 (Amtrak, 1994)
4 Heavy-rail vehicles in the transit fleet, 1993: 10,261(APTA, 1994)
4 Light-rail vehicles in the transit fleet, 1993: 1,025 (APTA, 1994)
4; Commuter rail cars in the transit fleet, 1993: 4,494 (APTA, 1994)
VEHICLE PURCHASES
The number of vehicles purchases each year provides some insight into the environmental effects of
vehicle manufacture, maintenance, and disposal. • •
4 New freight cars installed, 1993: 35,239 (plus 8,093 rebuilt cars) (AAR, 1994)8
4 New locomotives installed, 1993: 504 (plus 217 rebuilt units) (AAR, 1994)9
4 New passenger rail cars purchased by Amtrak and commuter railroads, 1992: 110 (Eno,
1994)
4 New urban transit rail cars purchased by transit authorities, 1992: 198 (Eno, 1994)
4 Including rebuilt cars, 9Lpassenger cars were delivered to Amtrak, and 353 passenger cars
(rapid .transit, commuter, and light-rail) were delivered to metropolitan transit authorities in
the U.S. in 1994.10 . •
TRAVEL
The level of travel provides an indication of certain impacts, such as emissions from diesel
locomotives and energy consumption by electric vehicles.
Freight traffic dominates the total number of car miles traveled by rail, with intraregion transit a
minor second, and intercity travel third.
4 Total railcar miles traveled, 1992: 28.98 billion miles11
Type of Travel
Freight
Transit
Amtrak ,
Railcar miles traveled Percentage
of total
27,900,000,000 miles
777,000,000 miles
302,000,000 miles
96.3
2.7
1.0
Freight: AAR, 1993 plus 3.8% (Eno, 1994) to reflect other Class H and m traffic;
Amtrak: AAR, 1993; Transit: APTA, 1994
7 Includes all railroads and private car companies
Includes those installed by Class I railroads, other railroads, and private car owners.
9 Includes those installed by Class I railroads, other railroads, and private car owners.
10 Railway Age. January 1995.
11 Freight: AAR, 1993 plus 3.8 percent (Eno, 1994) to reflect other Class II and III traffic; Amtrak: AAR, 1993;
Transit: APTA, 1994
A-15
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Indicators of the Environmental Impacts of Transportation
FREIGHT TRAVEL
4 Freight ton-miles transported by rail in 1992 was 1,107 billion miles; 37.4 percent of total
freight ton-miles were transported by rail (Eno, 1994).
4 The average freight rail trip length was 673 miles (Eno, 1994).
4 In 1992, 1,646 million tons of freight were transported by rail; 25.0 percent if total freight
tonnage was transported by rail (Eno, 1994).
4 Average number of cars per freight train, .Class I, 1993, was 66.4 cars (AAR, 1993).
4 Average tons per carload, Class I, 1993, was 64.4 tons (AAR, 1993).
4 Average length of haul, Class 1,1993, was 794 miles (AAR, 1993).
4 Number of Class I revenue car loadings in 1993 was 21,682,894 (AAR, 1993).
PASSENGER TRAVEL
4 Rail passenger miles traveled, 199" : 25.3 billion miles (AAR, 1993).
4 Over 40 percent of all passenger miles traveled on rail systems in the United States was on
heavy rail (subway or elevated) systems.
Passenger Rail Travel, 1993
Type of Rail Service
Amtrak
Commuter Rail
Heavy Rail
Light Rail
Total
Passenger Miles Percentage of Total Average Trip Length
Traveled (millions} : 'V.V ';";' ". r '!':'•.. :.' •'•.'••,'• •••'dttOiiisl'.
6,319
7.489
10,740
705
, 25,253
25.0
29.7
42.5
2.8
100.0 '
271.1
21.5 '
3.8
1.6
'
Source: Eno, 1994; APTA, 1994
Because large transit systems .are located in the largest metropolitan areas, the vast majority of all
customers are in the largest U.S. cities, and especially the Northeast. The New York City
metropolitan area dominates nationally, with approximately 3.5 million subway customers on an
average weekday, and about one billion subway passengers per year (New York City MTA, 1994b).
Overall, about 4 out of every 10 mass transit trips in the United States occur in New York City (New
York MTA, 1994a).
ENERGY CONSUMPTION
Energy consumption provides an indication of total emissions and resources consumed by rail
transport.
4 Energy consumption, 1992: 505.7 trillion Btus. The majority of energy consumption is in
frieght operations. Overall, rail transport consumed 2.2 percent of total transportation sector
energy consumption (DOE, 1994a).
A-16
-------
Infrastructure and Travel Measures
Freight ' 425.4 Btus-
Passenger ' 61.7Btus
dieselfuel 441.2 Btus
electric power , 59.2 Btus
All electric-powered rail is used in passenger operations, not freight.
A-17
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Indicators of the Environmental Impacts of Transportation
MODE: A VI XT-TON
INFRASTRUCTURE
The number of aircraft and airports is a crude estimate of the some environmental impacts, such as
noise, emissions, habitat disruption and runoff. The increase in the number of aircraft may provide a
basic indicator of emissions and the extent of noise. It is important to remember, however, the newer
aircraft are more efficient in terms of fuel consumption and emissions and that increases in the
number of aircraft are not likely to be associated with a similar increase in emissions. The same is true
for noise—newer aircraft are required to meet the quieter Stage 3 noise standards.
AIRPORTS
The number of airports is a basic indicator of habitat disruption and runoff. Although only one major
new airport has been constructed in the last 20 years, there has been construction of a number of
smaller public and private airports. This increase in airports in general, may have implications on
habitat and runoff.
+ There were 18,343 airports in the U.S. in 1994, which is more airports than in every other
nation in the world combined (U.S. DOT, BTS, 1994).
4- The number of airports in the U.S. has increased by 3,182 from 1980 to 1992—a nearly 21
percent increase—from 15,161 in 1980 to 18,343 in 1994 (U.S. DOT, BTS, 1994).
Year
1980
1990
1992
1993
1994
Number of Airports
15,161
17,490
17,846
18,317
18,343
Source: U.S. DOT, BTS, 1994
Airports vary significantly in size. The U.S. contains 26 large hub airports (handling 1
percent or more of total air passenger enplanements) and 570 commercial service'airports
(2,500 or more enplanements annually) (U.S. DOT, BTS, 1994). Most airports are small
private-use airports, many of which have unpaved runways, as the following table shows:
U.S. Airports, 1992
Public-Use Airports
Private-Use Airports
Total All Airports
Number
5,545
12,301
17,846
Percentage
with Paved
Runways-
71.7
36.6
47.5
Percentage with
Lighted
Runways
72.3
7.6
27.7
Source: U.S. DOT, BTS, 1994
A-18
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; _ Infrastructure and Travel Measures
AIR CARRIER FLEET
4 World air earners placed orders for an estimated 490 large jet aircraft with U.S. and foreign
• aircraft manufacturers during FY 1995, 54.0 percent more orders than in 1994. Of this total,
338 (69.0 percent) were for two-engine narrowbody (B-737, B-757, MD-80, MD-90, A-
^ 320/321 and F-100) aircraft (Boeing, 1995).
* Aircraft manufacturers delivered approximately 449 large jet aircraft worldwide in 1995. Of
this total, 287 (63.9 percent) were two-engine narrowbody aircraft, and 90 (20.0 percent)
were for two-engine widebody aircraft (Boeing, 1995).
* At the year ending December 1995, the fleet for U.S. air carriers increased by an estimated
138 aircraft, an increase of 3.0 percent.' This compares with 1994, when the fleet increased
by 156 aircraft (U.S. DOT, BTS, 1995).
* Total fleet of air carriers has increased, while the fleet of general aviation aircraft has
decreased, since 1980 (U.S. DOT, BTS, 1994).
Year
1980
1990
1992
1993
1994
Number of Aircraft
Air Carrier
2,818
4,727
4,884
'. 5,234
5,221
General
Aviation
202,487
196,800
183,620 '
176,006
170,600 -
Source: U.S. DOt, BTS, 1994
TRAVEL
Demand for aviation has grown rapidly over the last 30 years and is expected to continue to do so for
the next decade. For.example, passenger enplanements, a key measure of demand for air services, has
grown by an average of 1.27 percent annually over the last 10 years. Underlying this basic statistic,
however, are a series of important trends that can have a direct influence on the implications for
environmental impacts. For example, perhaps the single most important determinant of the level of
environmental impact of aviation activity is aircraft operations (takeoffs and landings), which
indicate the overall number of aircraft flights.
Operations are a function of several factors that change over time:
* Passenger and cargo demand (domestic and international)
4 Aircraft load factors (the percentage of seats or cargo space filled)
4 The amount of "hubbing" (connecting)
4 Aircraft size
Combined aircraft operations have grown little over the last 5 years despite rapidly increasing travel
demand. This slow growth has been due in large part to dramatic increases in aircraft load factors.
A-19
-------
Indicators of the Environmental Impacts of Transportation
However, as load factors approach a technical maximum, the number of commercial operations will
need to grow to meet demand. As a result, the environmental impacts per passenger may increase.
Still, environmental consequences are a function of a number of factors, including operations and
aircraft engine efficiency.
Activities associated with airport operations are discussed below.
TOTAL COMBINED AIRCRAFT OPERATIONS AT AIRPORTS
Total combined aircraft operations (takeoffs and landings) at airports, including air carrier, air
taxi/commuter, general aviation and military categories totaled 62.5 million in 1995, representing a
0.3 percent increase from 1994 (U.S. DOT, FAA, 1996).
Fiscal Year
1985
1986
1987
1988
1989
1990
1991
1992
1993
1994
1995
2007*
*projcctlon
Source: U.S.
Total Combined
,, Aircraft
Operations at
Airports
(InMillions)
57.9
59.0
61.0
61.3
61.4
64.9
62.8
63.2
61.9
62.3
62.5
74.5
DOT, FAA, 1996.
Total Combined Aircraft Operations at
1990
1995 2000
Fiscal Year
2005 2010
REVENUE PASSENGER MILES
* U.S. scheduled air carriers recorded .a total of 558 billion revenue passenger miles in 1995,
up 3.6 percent from the previous year (U.S. DOT, BTS, 1997).
4 International growth is anticipated to be somewhat higher than domestic growth, with the
average annual growth in RPMs during the 1995-2007 forecast period being 5.3 percent,
compared with 3.8 percent for the domestic market (U.S. DOT, FAA, 1996).
* In the year 2007, the international share of the U.S. carriers' system RPMs is expected to be
30.2 percent, up from 26.9 percent in 1995 and 21.1 percent in 1980 (U.S. DOT, FAA,
1996).
12 Energy use includes fuel purchased abroad for international flights.
A-2Q
-------
Infrastructure and Travel Measures
DOMESTIC REVENUE PASSENGER MILES
Scheduled domestic revenue passenger miles (RPMs) totaled 392.4 billion in 1995, up 5.7
percent from 1994 (U.S. DOT, FAA, 1996). This outcome was largely the result of the
relatively strong growth in the economy and the continued decline in real yields.
Revenue Passenger Miles
700
Fiscal Year
1985
1986
1987
1988
1989
1990
1991
1992
1993
1994
1995
2007*
projection
Source: U.S.
'Revenue
Passenger Miles
" (billions)
330,6
358.5
398.1
416.0
429.0
339.2
333.6
346.7
348,6
371.3
392.4
617,3
DOT,' FAA, 1996.
1985 1990
1995 2000
Fiscal Year
2005 2010
INTERNATIONAL REVENUE PASSENGER MILES
* International RPMs grew 4.1 percent in 1995. The growth was uneven, however, with
increases of 10.4 percent in Latin American markets, 6.0 percent in Pacific markets, and only
0.3 percent in Atlantic markets (U.S. DOT, FAA, 1996).
i
* Total RPMs in international markets are expected to approximately double during the
forecast period, increasing from 144.2 billion in 1995 to 266.6 billion in 2007. The average
annual growth rate over this period is 5.3 percent (U.S. DOT, FAA, 1996).
PASSENGER ENPLANEMENTS '
4 In 1995, U.S. scheduled air carriers enplaned a total of 544.3 million passengers (U.S. DOT,
FAA, 1996). , .
4 Overall average annual growth in system passenger enplanements for the 12-year forecast
period, 1995-2007, is expected to be 3.9 percent (U.S. DOT, FAA, 1996).
. 4 In 1995, 91.1 percent of enplanements were domestic. This will drop to 89.5 percent in 2007
(U.S. DOT, FAA, 1996).
A-21
-------
Indicators of the Environmental Impacts of Transportation
DOMESTIC PASSENGER ENPLANEMENTS
* Domestic passenger enplanements (495.9 million) increased by 5.1 percent in 1995; in 1994
the increase was 8.8 percent (U.S. DOT, FAA, 1996).
•Fiscal
5'Year
1985
1986
1987
1988
1989
1990
1991
1992
1993
1994
1995
2007*
Domestic
Passenger
Enplanements
(millions)
*projection
Source: U.S.
375.0
409.8
444.9
448.5
452.4
424.1
413.3
430.3
434.0
472.0
495.9
766.8
DOT, FAA, 1996.
Revenue Passenger Enplanements
1985 1990
1995 2000
Rscal Year
2005 2010
* The growth in domestic enplanements is expected to average 3.7 percent during the 12-year
forecast period, with the number of domestic enplanements reaching 766.8 million in 2007
(U.S. DOT, FAA, 1996).
INTERNATIONAL PASSENGER ENPLANEMENTS
' V
* A total of 48.4 million passengers were enplaned by U.S. scheduled international airlines in
1995, up 4.6 percent (U.S. DOT, FAA, 1996).
* The average annual rate of growth during the 1995-2007 forecast period will be 5.3 percent
(U.S. DOT, FAA, 1996).
PASSENGER LOAD FACTOR
* U.S. scheduled air carriers recorded a system-wide load factor of 66.8 percent in 1995, up
significantly from the previous peak of 65.7 reached in 1994 (U.S. DOT, FAA, 1996).
A-22
-------
Infrastructure ahd Travel Measures
DOMESTIC PASSENGER LOAD FACTOR
* U.S. scheduled domestic air carriers had a load factor of 65.2 percent in 1995, up 1.0 point
from 1994. Domestic load factors have varied very little over the period 1985 through 1993<
ranging from a low of 60.3 percent in 1986 to 65.2 percent in 1995 (U.S. DOT, FAA, 1996).
4 Capacity increased 4.1 percent between 1994 and 1995 (U.S. DOT, FAA, 1996).
INTERNATIONAL PASSENGER LOAD FACTOR •
4 The international load factor edged up to 71:4 percent in 1995, up from 70.0 percent in
1994—the highest annual load factor in history. The previous high of 69.2 percent was
achieved in 1990 (U.S. DOT, FAA, 1996). ,
4 The international load factor is forecast to remain relatively stable over the twelve year
forecast period, increasing from 71.4 percent in 1995 to 71.6 percent in 2007 (U.S. DOT,
FAA, 1996),
Am CARGO TRAFFIC
4 Air cargo revenue ton miles (RTMs) flown by U.S. air carriers reporting on BTS Form 41
totaled 23.2 billion in 1995, up 11.5 percent from 1994 (U.S. DOT, FAA, 1996).
4 Freight/express RTMs increased 12.5 percent, while mail RTMs increased 4.4 percent. .
Domestic cargo RTMs were up 9.0 percent, while international RTMs increased 14.4 percent
(U.S. DOT, FAA, 1996).
ENERGY CONSUMPTION
4 Energy consumption by air carriers has increased significantly since 1970.
Energy Use By Air Carriers13
Year Energy Use v Energy Use By Air Carriers
(trillion Btn)
1970 1363.4 ' ' -
1975 1283.4
1980 ~~1489.6
1985 1701.5 ~
1990 2191.3
1991 2069.2 " '
1970 1975 1980 1985 1990 1995
1992 2144.2
Year
Source: U.S. DOE. 1994a.
13 Energy use includes fuel purchased abroad for international flights.
A-23
-------
Indicators of the Environmental Impacts of Transportation
Change in Energy Use per Passenger Mile, 1970-92
aair/o
300%
250%
200%
150%
100%
50%
-50%
-100%
-1KIW.
275%
-
-
-
-
Passenger Mile
Passenger Total Energy
Miles
Use ,58%
JET FUEL CONSUMPTION
Fuel consumption in aviation increased to a record high of 17,795 million gallons in 1995.
Fiscal Year
Total Jet Fuel &
Aviation Gasoline
Fuel Consumption
(millions of gallons)
1985
13,437
1986
14,412
1987
15,313
1988
16,146
1989
16,713
1990
17,207
1991
16,590
1992
16,610
1993
16,754
1994
17,163
1995
17,795
2007»
27,156
*projeetion
Source: U.S.
DOT, FAA, 1996.
in
c
o
75
O
a>
O
Total Jet Fuel Aviation & Gasoline
Fuel Consumption
30,000 r
25,000
1
1985 1990 1995 2000 2005 2010
Fiscal Year
PASSENGER TRIP LENGTH
* The average system passenger trip length (986 miles) increased by 2.1 miles in 1995, largely
the result of increases in trip lengths in the domestic, Atlantic, and Latin American routes
(U.S. DOT, FAA, 1996).
* The domestic passenger trip length increased about 5 miles, primarily due to some of the
major carriers eliminating short-haul markets and/or turning these markets over to their code-
sharing regional partners (U.S. DOT, FAA, 1996).
A-24
-------
Infrastructure and Travel Measures
4 In 1995, seven put of the nine majors increased their trip lengths, while the average domestic
trip length for all major carriers increased more than 7 miles (U.S. DOT, FAA, 1996).
AIRBORNE HOURS
4 U.S. commercial air carriers flew an estimated total of 11.9 million hours in 1995, up from
11.5 million hours in 1994 (U.S. DOT, FAA, 1996).
Fiscal Year
1985
1986
1987
1988
1989
1990
1991
1992
1993
• 1994
1995
2007* '
*projection
Source: U.S.
Total Airborne
' Hours
(in thousands)
7,718
8,774
9,397
9,842
10.097
10,457-
' 10,480
10,679
11,138
' 11,482
11,940
18,212
DOT, FAA, 199<
CO
•o
05
eo
o
20,000
18,000
16,000
14,000
12,000
10,000
8,000
6,000
4,000
2,000
Total Airborne Hours
1985 1990 1995 2000 2005 2010
Fiscal Year
Two aircraft categories accounted for over three fourths of total airborne hours: two-engine'
narrowbody aircraft (63.9 percent) and three-engine narrowbody (13.0 percent). In 2007, the
number of hours is forecast to increase to 18.2 million, an average annual increase of 3.7
percent. - . '
Two-engine aircraft (both narrowbody and widebody) are projected to account for 85.7
percent of all airborne hours flown in 2007. Two-engine narrowbody aircraft make up 15.1
percent of the hours in 2007, up an average of 9.1 percent per year (U.S. DOT, FAA, 1996).
The number of hours flown by three-engine narrowbody aircraft will decline significantly
over the forecast period. Hours for this aircraft type drop from 1.6 million in 1995 to 0.9
million in 2007, of 44.6 percent (U.S. DOT, FAA, 1996).
A-25
-------
Indicators of the Environmental Impacts of Transportation
MQDE: MARITIME
INFRASTRUCTURE
NAVIGABLE WATERWAY MILEAGE
4 Mileage of commercially navigable waterways has remained stable since 1990.
Mileage of Commercially Navigable Waterways
"!" ..... 1970 ; " '.. ....... j98o ....... .ig&oi:?':,:^^ 71993 ............. ' ....... 1994 ...........
25,253 25,543 . 25,543 25,777 25,777 25,777 25,777
Source: U.S. DOT, BTS, 1996.
MARITIME VESSELS
4 The vast majority of vessels in the U.S. are recreational boats.
Number of U.S. Vessels
I960 ~ 137ti ............. iSfSO "'.". "•".'-"• llS^'""^:""'-riM2"'V:--V
1 ::„'" , i!-^,''' ...... ;»"!'! .'I f ', "''"'-"i, |!'"!r IlSiih1 ir ....... "I1*!1,,,! "I. * : ...... 1,1:" M1 rf^F1!1 ;;r*' ^iiii'iA;;!^:^;';1 (::,:'i ^?z^:3^®»^'i:®»M»^^^^^:*
iType of Vessd _ .- . .. .•• ••;• .; '.'•-.:' ":f.-:--''v ,r\ : ;;?:vi^/-' A----V;- ;-:
Non-self-propelled 16,777 19,377 31,662 31,017 30,899 30,785 30,723
Total self-propelled 6,543 6,455 7,130 8,216 8,311 8,323 8,341
Total U.S. flag 5,852 1,579 864 636 603 564 543
merchant marine
Recreational _ : _ 8.600,000 11,000,000 11,100.000 11,300,000 11,400,000
Source: U.S. DOT, BTS,' 1996.
PORTS
4 There were 196 commercial ports (ports receiving commerce over 1,000,000 tons) in the
U.S. in 1993 (U.S. DOT, BTS, 1995b).
A-26
-------
Infrastructure and Travel Measures
TRAVEL
VESSEL USE
U.S. Ports, Ranked by Total Tons Shipped in 1993
PfsWffc j*0ft N3JBGMJ •" •"•
1
2
3
4
5
6
7
• 8
9
10
Port of South Louisiana, LA
Houston, TX
New York, NY &NJ
Valdez, AK
Baton Rouge, LA
New Orleans, LA
Corpus Christi', TX
Long Beach, CA
Texas City, TX
Plaquemine, LA
Tons Shipped
193,796,104
141,476,979
116,735,760
85,722,337
85,078,863
67,037,285
59,649,751
54,320,932
53,652,781
' 53,110,120
Source: U.S. Army Corps of Engineers, 1993.
Although the typical recreational boat is used less often (days per year) than other vessels,
recreational boats comprise the majority of vessel days.
Vessel Utilization in the U.S. Maritime Sector14
Day sot Vessel Use Per
' W
Year
Estimated Annual
JfoBBheritf Vessd Days
Recreational Boats
Hshing Vessels
Cargo Ships
Day Boats
U.S. Navy Vessels
U.S. Coast Guard Vessels
U.S. Army Vessels
School Boats
Offshore Industry Service Vessels
Navy Combatant Surface Vessels
Passenger Cruise 'Ships
Research Vessels
Misc. Private Industry Vessels
. Total
7,300,000
129,000
7,800
5,200
284
2,316
580
. 14
1,500
'. 360
128
125
85
7,447,392
21.9
240.9
350.4
240.9
120.5
109.5
73.0 •
127.8
365.0
120.5
350.4
200.8
365.0
159,870,000
31,076,100
2,733,120
1,252,680
34,222
253,602
42,340
1,789
547,500
43,380
44,851
25,100
31,025
195,955,709
Adapted from National Research Council, 1995.
14
U.S. maritime sectors include foreign-flag vessels that call at U.S. ports in addition to all U.S.-flag vessels.
Data were collected from various sources dating from 1990 to 1994. Number of vessels was tabulated as
follows: Recreational boats: boats registered in coastal states or in states bordering the Great Lakes. Cargo Ships:
different ships of all flags calling at U.S. ports.
A-27
-------
Indicators of the Environmental Impacts of Transportation
Coastwise and internal shipping of freight on water (in ton-miles) has increased significantly
from I960 to 1994, while lakewise and intraport ton-miles have fallen.
Ton-Miles of Domestic Water Freight
I III 1 1 T ill ] II 1 i
Place of Travel
Coastwise
Internal
Lake wise
Intraport
ll ii i mill in 111 i in
1960
256,000
89,614
65,990
1.730
f IT i1 ii '
1970
359,748
155,816
79,416
1,179
1980
631,149
227,343
61,747
1,596
*1990
479,134
292,393
60,930
1,087
*" * 1992
502,311
297,639
55,785
950
1993 *
448,404
283,894
56,438
921
' * 3.994
457,601
297,762
58,263
1,293
Source: U.S. DOT, BTS, 1996.
Average Length of Haul for Domestic Interstate Freight Vessels
UK "
Place of Travel
Coastwise
Internal
Likewise
P n i i ||i
1960 *
1,496
282
522
«)i if i
¥ 1 « r f
197Q
1,509
330
506
1980
1,915
405
536
1990
1,604
469
553
1992
1,762
479
519
1993
1,650
468
514
Source: U.S. DOT, BTS, 1996.
* Petroleum and petroleum products comprise the majority of waterborne freight traffic, in ton-
miles.
Domestic Waterborne Freight Traffic, 199315
............. l ............ ; ......... • ....... |i .................... , .i; .......... 4|.i<;iiii< i.,. ..... AH Bodies .; t Coastwise Lakewise , Internal Intraport
' ' " " ' '" "' '
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Infrastructure and Travel Measures
Refined Petroleum Products Transported by Water Carriers in the U.S.
Year
~
,'BaifoasofToH- JP«r«mtage«TTata!U,S.
" ~ -eleisan Products
Transportation
1975
1980
1985
1990
1991
1992
1993
257.4
230.4
141-.2
157.8
152.2
158.0
146.2
50.0
46.8
' . . - 34.5
35.2
35.0
35.5
32.7
Source: U.S. DOT, BTS, 1996.
FUEL CONSUMPTION
* Vessel fuel consumption has decreased during the time period 1980 to 1993.
Fuel Consumed by U.S. Vessels
Thousands of Barrels Consumed
197S
1988
1990
1992
'1993
Diesel fuel & distillate
Residual fuel oil
Gasoline
Total
18,730
94,084
9,200
122,014
19,503
89,850
' 14,238
123,591
35,201
213,131
25,048
273,380
52,310
148,764
30,962
232,036
52,824
171,407
31,337
255,568
48,661
149,283
20,802
218,746
Source: U.S. DOT, BTS, 1996.
A-29
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Additional Statistics on Impacts
APPENDIX B. ADDITIONAL STATISTICS ON
Monetized values of health and welfare effects are useful because they measure the ultimate outcomes
of pollution in comparable units. The weakness with using these indicators is that they are often
uncertain. Given the numerous assumptions and methods that are used to determine the actual
outcomes and the appropriate dollar values to assign to these outcomes, a broad range of dollar values
• appears in the literature. While these estimates are useful for understanding the magnitude of various
problems, they are listed in this appendix separately from the other indicators because of the higher
degree of uncertainty about these estimates and because monetized estimates are not available for
many impacts. • .
EfFECTS '
Health effects are an end result of pollutant emissions. As an outcome measure, health effects are an
ideal indicator of harm caused by transportation activities, providing direct and useful information on
the results of pollution. In practice, however, this indicator is somewhat problematic due to a high
degree of uncertainty in estimates. .
Estimating health effects requires use of dose-response functions which explain the human health
response to a particular dose of a pollutant over a period of time. The proper population exposure
must be estimated in combination with the dose-response function in order to determine health
impacts properly: Sub-populations which are most affected, such as children or asthmatics, may be
separated if separate dose-response functions have been developed.
Since the dose-response function is based on an ambient-level "dose" of pollutant, the portion of the
ambient level that is attributable to transportation sources must be estimated. Various methods might
be used to estimate how auto emissions affect ambient levels of air pollution, and these may be quite
complex,, involving dispersion models which take into account geography, climate, wind, natural
barriers, and other elements of topography. Difficulty arises since some ambient pollutants, such as
ozone, are not emitted directly from vehicles. Instead, ozone is formed through a process which
involves NOX and VOCs as precursors. Even if transportation is responsible for 30 percent of NOX
emissions in a region, transportation may not be responsible for 30 percent of the ozone in the"
atmosphere.
A number of estimates are listed below, some developed through very simplified methodologies:
4 Ketcham and Komanoff (1993) estimate that air pollution from motor vehicles causes 15,000
deaths annually, based on 75,000 deaths annually from air pollution with 20 percent
attributable to motor vehicles.16 '
* Delucchi, Sperling, and Johnson (1987) assume that motor vehicle air pollution causes 7,500
to 31,250 deaths annually, based on 15-25 percent of 50,000 to 125,000 deaths from air
pollution annually.17 -
16 Ketcham, B. and C. Komanoff, 1992. . ,
Delucchi, M., D. Sperling and R. Johnson. A Comparative Analysis of Future Transportation Fuels. UC-
Berkeley, 1987, as cited in Litman, 1994.
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Indicators of the Environmental Impacts of Transportation
* McCubbin and Delucchi (1995) estimate various adverse health affects from motor vehicles
using dose-response functions, as listed in the following table.18 Their findings suggest that
paniculate matter, especially road dust, is responsible for the majority of health effects,
including from 50 to 70 million cases of respiratory-related restricted activity days (RRAD)
annually, and 19,700 to 46,100 cases of chronic respiratory illness.
Estimated Cases of Adverse Health Effect (thousands of cases), 1991 from Motor Vehicle
Pollution
Health
Effect
Mortality
Airway
obstructive
disease
(chronic
respiratory
illness)
Respiratory-
related
restricted
activity days
(RRAD)
Cancer-oral
Cancer-lung
Cancer-
Leukemia
Cancer-other
Asthma
attacks
Headaches
Excess
phlegm
Eye irritation
Sore throat
Lower
respiratory
illness
Upper
respiratory
illness
Air Pollutant
CO
852,251
NOx, in a
£
nitrate
PM
2.8
1.3-3.1
4,994 -
6,960
65
unbient air
s:
NO2
139,184 -
140,153
63,860 -
64,322
57,462 -
57.871
SOx
Sulfate
PM
0.9
0.4 - 1.0
1,502 -
2,087
J
21
Direct
PM
33.3
17.7-
41.6
42,948 -
59,899
1,115
VOCsina
a
Organic
PM
0.3
0.1 - 0.3
510-
712
7
unbient air
s:
Ozone
0-3.8
2,879
-
17,533 -
23,592
9,676 -
13,008
18,179-
24,440
Toxics
0.01
0.23
0.06
0.23
Total
37.3-41.1
19.7-46.1
49,954 -
69,658
0.01
0.23
0.06
0.23
4,087
852,251
139,184 -
140,153
57,462 -
57,871
9,676 -
13,008
18,179-
24,440
Source: McCubbin and Delucchi. Health Effects of Motor Vehicle Air Pollution. July 1995.
is McCubbin, D. and M. Delucchi. 1995.
B-2
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ff!
.1
S
ON
CS
«
"3
a!
o
"><
o
fr-l
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Indicators of the Environmental Impacts of Transportation
MO NET 12 Eft V AX UES
HIGHWAYS
TAILPIPE AND EVAPORATIVE EMISSIONS
Emissions from vehicle travel are responsible for five major categories of costs which may be
monetized:
4 Human health impacts
4 Materials damage
* Agriculture damage
* Visibility degradation
4 Global Warming
OVERALL AIR POLLUTION COSTS
• Moffet, 1993, estimates air pollution costs as $86 to $160 billion annually from autos and
$34 to $62 billion annually from light trucks.19
• Cannon, 1990, estimates total U.S. automobile emissions costs are approximately $50 billion
annually.
• The Office of Technology Assessment (1994) has estimated U.S. annual automobile air
pollution costs, including human health effects, global warming, agricultural losses, material
effects, visibility and aesthetic losses, to range from $47 to 242 billion.20
• Litman (1994) estimates national air pollution costs as $110 billion.21
HUMAN HEALTH COSTS
• McCubbin and Delucchi estimate emissions from auto travel are responsible for $64 to 223
billion per year in health costs in 1991, including road dust. Parficulates are responsible for
about 93-97 percent of the total.22
• Ketcham and Komanoff (1993) estimate U.S. national automobile air pollution health costs
at $30 billion.
• Delucchi, Sperling, and Johnson (1987) estimate that roadway use causes from $7.5 to 181.3
billion per year in health damage (converted to 1991 dollars by DRI/McGraw-Hill).
MATERIALS DAMAGE
• Emissions from auto travel have been estimated as responsible for about $4 billion dollars
annually in materials damage.
• Delucchi, Sperling, and Johnson (1987) estimate that roadway use causes from $3.9 to 11.7
billion per year in materials damage (converted to 1991$ by DRI/McGraw-ttill).
l9Moffet,1993,p.48.
^ILS. Officeof Technology Assessment. Saving Energy in U.S. Transportation. 1994, p. 108, as cited in
Litman, 1994.
21 Litman, T. Transportation Cost Analysis: Techniques, Estimates and Implications. December, 1994. p.
3,10-8.
22 McCubbin and Delucchi. 1995. Table 6.
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AGRICULTURE DAMAGE ' .
• Emissions from auto travelhave been estimated as responsible for about $1.3 to $3.5 billion
dollars annually in damage to crops and agriculture.
• Delucchi, Sperling, 2nd Johnson (1987) estimate that roadway use causes from $2.0 to 8.0
billion per year in crop damage (converted to 1991$ by DRI/McGraw-Hill).
VISIBILITY DEGRADATION
• Emissions from auto travel have been estimated as responsible for about $4 billion dollars
annually in visibility loss. ,
• U.S. aesthetic costs of smog have been estimated at $7.9 billion annually in 1982 (Crandall,
Robert, et al. Regulating the Automobile, Brookings Institute, Washington DC, 1986).
GLOBAL WARMING
• Emissions from auto travel have been estimated as responsible for about $26 billion dollars
annually from the risk of global warming.
• DRI/McGraw-Hill (1994) estimates that roadway use is responsible for $1.8 to 8.6 billion
dollars per year in damage from climate change (1991$)
FUGITIVE DUST FROM ROADS
• McCubbin and Delucchi estimate that fugitive dust caused $59 to 216 billion dollars in
human health cost damages in 1991.23
• The monetized cost of health damage from fugitive dust exceeds the health damage costs
from tailpipe and evaporative emissions.
NOISE AND VIBRATION
• Ketcham (1991) estimates that roadway use is responsible for $4.1 to 6.6 billion dollars in
noise damage annually (1991 $).24
• Konheim and Ketcham (1991) estimate that roadway use is responsible for $0.3 billion
dollars in vibration damage annually (1991 $).25
• Ma'cKenzie used estimates developed by Hokanson for the U.S. DOT to calculate total U.S.
noise costs from roadway use to be $9 billion annually.26
• Changes in the value of U.S. houses between 0.08% and 0.88% occur per one unit change in-
Leq.27 '
23 McCubbin and Delucchi. July 1995. Table 6. • "
24 Ketcham, Brian. Making Transportation Choices Based on Real Costs. October 1991, as reported by
DRI/McGraw-Hill, 1994.
25 Konheim and Ketcham. "Toward a More Balanced Distribution of Transportation Funds." Draft, 1991,
as cited in DRI/McGraw-Hill, 1994.
26 MacKenzie, J., R. Dower and D. Chen. The Going Rate. World Resources Institute, Washington, DC.,
1992, p.21. , - -
27 Pearce and Markandya, 1986 and Button, 1990, as cited in Moffet, 1993, p. 34.
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Indicators of the Environmental Impacts of Transportation
LEAKING FUEL TANKS AND OIL SPILLS
• The Office of Technology Assessment (1994) estimated that leaking fuel tanks and oil spills
associated with motor vehicle use cost $1 to 3 billion per year in the U.S.28
* Lee estimates that annual uncompensated oil spills average $2 billion.29 •
ROADWAY DEICING
• An Apogee survey of cost estimates of damage attributable to roadway deicing found a range
of from about $4.7 billion to $8 billion annually. ,
* Murray and Ernst (1976) estimate damage from road salting nationwide is $4.7 billion
annually (converted to 1993$ by Lee).30
• A 1976 EPA study identified $8 billion in damages (1990 dollars) from road salt. Over 90
percent of this damage was to vehicles and highway structures. $600 million was damage to
water supplies, health, and vegetation.31 . ' .
* NRDC estimates the aesthetic damage to vegetation caused by road de-icing is about $650
million per year32
WASTE DISPOSAL
• Lee estimates external waste disposal costs associated with highways as $4.2 billion. This
value includes $0.5 billion for waste oil, $0.7 billion for' scrapped cars, and $3.0 billion for
used tires.33
as U.S. Office of Technology Assessment. Saving Energy in U.S. Transportation. 1994, p. 108, as cited in
Litman, 1994.
29 Lee, D. Full Cost Pricing of Highways. Paper presented at TRB. 1995:
30 Murray and Ernst. Economic Assessment of the Environmental Impact of Highway Deicing. EPA, 1976,
as cited in Litman, 1994.
31 1976 EPA study (Murray and Ernst), as cited by NRDC, 1993.
32 NRDC, 1993, p. 50.
MLcc, D. Full Cost Pricing of Highways. Paper presented at TRB. 1995.
B-6
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