Indicators of the Environmental Impacts of Transportation, Updated Second Edition


          United States
          Environmental Protection
          Agency	
             Policy
             (2126)
             Washington, DC 20460
EPA 230-R-99-001
October 1999
r/EPA
Indicators of the Environmental
Impacts of Transportation
          Updated Second Edition

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                                       Foreword
This is the second edition of a report issued by the U.S. Environmental Protection Agency on the
environmental impacts of transportation in the United States. This report compiles national-level
data on the effects of transportation on all environmental media — air, water, and land — and
highlights environmental statistics that can be used to assess the magnitude of transportation
impacts and track trends over time. It addresses a broad range of transportation-related activities,
including infrastructure construction, vehicle and equipment manufacture, travel, operations and
maintenance, and disposal. The document is designed as  a reference for policy-makers,
researchers, and others interested in the multi-media impacts of our nation's transportation
system.

This report was prepared under contract #68-W4-0041 for the U.S. Environmental Protection
Agency, Office of Policy, Energy and Transportation Sectors Division, by Hagler Bailly
Services, Inc. EPA is pleased to acknowledge the input received during the initial report
preparation process from representatives of the U.S.  Department of Transportation (Office of the
Secretary, Bureau of Transportation Statistics, Federal Aviation Administration, Federal
Highway Administration), the U.S. Department of Energy, and the Center for Transportation and
the Environment at North Carolina State University.

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                             TABLE OF CONTENTS
1. Introduction	1
   1.1 Background	1
   1.2 .Definition of Indicators	5
   1.3 Presentation of Environmental Indicators	9
2. Indicators Summary	11
  2.1 Criteria Air Pollutants	11
  2.2 Toxics	.'	19
  2.3 Greenhouse Gases	20
  2.4 Chloroflourocarbons and Stratospheric Ozone Depletion	23
  2.5 Habitat and Land Use	24
  2.6 Water Quality	28
  2.7 Hazardous Materials Incidents	31
  2.8 Noise	32
  2.9 Solid Waste	33
3. Highway Environmental Indicators	35
  3.1 Highway Infrastructure Construction	35
  3.2 Motor Vehicle and Parts Manufacture	42
  3.3 On-Road Vehicle Travel	49
  3.4 Maintenance, Support, and Operation	71
  3.5 Disposal of Vehicles and Parts	78
4. Rail Environmental Indicators	85
  4.1 Railway Construction and Abandonment	85
  4.2 Rail Car and Parts Manufacture	90
  4.3 Rail Travel	94
  4.4 Rail Operations, Maintenance and Support	104
  4.5 Disposal of Rail Cars and Parts	109
5. Aviation Environmental Indicators	Ill
  5.1 Airport Construction and Infrastructure Improvement	Ill
  5.2 Aircraft Parts and Manufacture	115
  5.3 Air Travel	123
  5.4 Aviation Operations and Support	137
  5.5 Disposal of Aircraft and Parts	146

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INDICATORS OF THE ENVIRONMENTAL IMPACTS OF TRANSPORTATION
6. Maritime Environmental Indicators	147
  6.1 Construction of Ports and Navigation Improvements	147
  6.2 Manufacture of Vessels and Parts	153
  6.3 Water-Borne Travel	160
  6.4 Maritime Terminal Operation	175
  6.5 Disposal of Vessels and Parts	180
7. Data Availability and Next Steps	181
  7.1 Data Sources Focused on the Environment	181
  7.2 Data Sources Focused on Transportation	186
  7.3 Data Gaps	187
  7.4 Next Steps	188

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                                   LIST OF TABLES
Table 2-1:


Table 2-2:


Table 2-3:

Table 2-4:


Table 3-1:

Table 3-2:

Table 3-3:

Table 3-4:

Table 3-5:

Table 3-6:


Table 3-7:



Table 3-8:


Table 3-9:


Table 3-10:


Table 3-11:


Table 3-12:


Table 3-13:


Table 3-14:
Core Toxic Chemicals Released from Transportation Manufacturing Facilities
(Subset of TRI Inventory) In Thousands of Pounds, 1988-1996	20

Full Fuel Cycle CO2-equivalent Emissions for Light-duty Motor Vehicles (grams
per mile)	22

Corrective Action Measures Reports for the Entire U.S., 1996-1998	30

Percent of U.S. Population Exposed to Different Levels of Transportation Noise,
1980	32

Wetland Losses and Creation Associated with the Federal Aid Highway Program	37

Land Area Occupied by Roadways, 1990-1997 (Square Miles)	38

Lane Miles, 1990-1997	38

Public Road Mileage, 1945-1997	39

Unpaved and Paved Public Road Mileage, 1945-1997	41

Toxic Chemicals released from Motor Vehicle-Related Manufacturing Facilities,
1996 (pounds per year)	44

Toxic Chemicals (Core) Released from Motor Vehicle-Related Manufacturing
Facilities (SIC 3711, 3713, 3714, 3715, 3716, 3717, and 3792), 1988-1996
(thousands of pounds per year)	45

Criteria Pollutant Emissions from Vehicle Manufacturing Facilities, 1990-1996
(short tons)	46

Criteria Pollutant Emissions from Vehicle Manufacturing Facilities by SIC Code,
1996	46

VOC Emissions from Solvent Utilization in Surface Coating for Autos & Light
Trucks (Point and Area Sources), 1970-1997	47
VOC Emissions from Motor Vehicle and Parts Manufacturing Facilities reported
to AIRS	47

CO Emissions from Motor Vehicle and Parts Manufacturing Facilities reported to
AIRS	48

NO2 Emissions from Motor Vehicle and Parts Manufacturing Facilities reported to
AIRS	48

SO2 Emissions from Motor Vehicle and Parts Manufacturing Facilities reported to
AIRS	48
                                                                                           iii

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INDICATORS OF THE ENVIRONMENTAL IMPACTS OF TRANSPORTATION
Table 3-15:    PMio Emissions from Motor Vehicle and Parts Manufacturing Facilities reported
              to AIRS	48

Table 3-16:    Criteria Pollutant Emissions from Motor Vehicle Travel, 1997	50

Table 3-17:    VOC Emissions from On-Road Vehicles, 1940-1997	51

Table 3-18:    VOC Emissions by On-Road Vehicle Category (thousand short tons), 1970-1990	51

Table 3-19:    NOx Emissions from On-Road Vehicles, 1940-1997	52

Table 3-20:    NOx Emissions by On-Road Vehicle Category (thousand short tons), 1970-1997	52

Table 3-21:    CO Emissions from On-Road Vehicles, 1940-1997	53

Table 3-22:    CO Emissions by On-Road Vehicle Category (thousand short tons), 1970-1997	53

Table 3-23:    PM,0 Emissions from On-Road Vehicles, 1940-1997	54

Table 3-24:    PM10 Emissions by On-Road Vehicle Category (thousand short tons), 1970-1997	54

Table 3-25:    PM2.5 Emissions from On-Road Vehicles, 1990-1997	55

Table 3-26:    PM2.5 Emissions by On-Road Vehicle Category (thousand short tons), 1970-1997	55

Table 3-27:    S02 Emissions from On-Road Vehicles	56

Table 3-28:    SO2 Emissions from On-Road Vehicle Category (thousand short tons), 1970-1997	56

Table 3-29:    Lead Emissions from On-Road Vehicles, 1940-1997	57

Table 3-30:    Lead Emissions by On-Road Vehicle Category (short tons), 1970-1997	57

Table 3-31:    Motor Vehicle Emissions of Toxic Pollutants, 1990	58

Table 3-32:    PM10 Fugitive Dust, Emissions by Road Type, 1985-1997	59

Table 3-33:    Carbon Dioxide Emissions by On-Road Vehicle Category (million metric tons of
              carbon)	60

Table 3-34:    Nitrous Oxide Emissions from Motor Vehicles (thousand metric tons)	61

Table 3-35:    Methane Emissions from Motor Vehicles (thousand metric tons)	62

Table 3-36:    Estimated U.S. Emissions of CFC-12 and HFC-134a (all sources), 1990-1997
              (thousand metric tons of gas)	64

Table 3-37:    Percent of U.S. Population Exposed to Road Transportation Noise, 1980	65

Table 3-38:    Length of Noise Barriers Constructed (miles) and Cost	65

Table 3-39:    Highway Hazardous Materials Incident Totals, 1990-1997	67
IV

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                                                                                LIST OF TABLES
Table 3-40:    Highway Hazardous Materials Incidents, 1997	68

Table 3-41: . . Highway Salt Sales, 1970-1997	73

Table 3-42:    Typical Motor Freight Terminal Operations: Materials Used and Types of Waste
              Possibly Generated	74

Table 3-43:    VOC Emissions from Service Stations, 1940-1997	76

Table 3-44:    Corrective Action Measures Reports for the U.S., 1996-1998	77

Table 3-45:    Motor Vehicle Scrapped Annually (thousands)	79

Table 3-46:    Rubber Tires in Municipal Solid Waste Stream, 1960-1996	82

Table 3-47:    Lead Acid Batteries in Municipal  Solid Waste Stream, 1960-1996	83

Table 4-1:     Rail System Mileage in the U.S., 1960-1996	87

Table 4-2:     New Rail and Crossties Laid by Class I Railroads, 1955-1996	89

Table 4-3:     Criteria Pollutant Emissions from  Vehicle Manufacturing Facilities, 1990-1996
              (short tons)	90

Table 4-4:     VOC Emissions from Solvent Utilization in Surface Coating for Rail Equipment
              (Point and  Area Sources), 1940-1997	91

Table 4-5:     Pollutant Emissions from Rail Equipment Manufacturing Facilities Reported to
              AIRS	91

Table 4-6:     Toxic Chemicals (Core) Released  from Railroad Equipment Manufacturing
              Facilities (SIC 3743), 1988-1996 (thousands of pounds per year)	93

Table 4-7:     Criteria Pollutant Emissions from  Railroad Operations, 1997	95

Table 4-8:     CO Emissions from Railroad Operations, 1940-1997	i	96

Table 4-9:     NOx Emissions from Railroad Operations, 1940-1997	96

Table 4-10:    VOC Emissions from Railroad Operations, 1940-1997	97

Table 4-11:    SO2 Emissions from Railroad Operations, 1940-1997	97

Table 4-12:    PM10 Emissions from Railroad Operations, 1940-1997	98

Table 4-13:    PM2.5 Emissions from Railroad Operations, 1940-1997	98

Table 4-14:    Carbon Dioxide Emissions from Fossil Fuel Combustion in Rail Travel (million
              metric tons of carbon)	99

Table 4-15:    Nitrous Oxide and Methane Emissions from Rail Travel, 1996	100

Table 4-16:    Percent of U.S. Population Exposed to Rail Transportation Noise, 1980	100

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INDICATORS OF THE ENVIRONMENTAL IMPACTS OF TRANSPORTATION
Table 4-17:

Table 4-18:

Table 4-19:


Table 4:20:

Table 4-21:

Table 4-22:

Table 4-23:

Table 4-24:


Table 5-1:

Table 5-2:

Table 5-3:


Table 5-4:


Table 5-5:


Table 5-6:


Table 5-7:

Table 5-8:

Table 5-9:

Table 5-10:


Table 5-11:

Table 5-12:


Table 5-13:

Table 5-14:
Railroad Hazardous Materials Incident Totals, 1990-1997	102

Railroad Hazardous Materials Incidents, 1997	103

Typical Railroad Terminal Operations: Materials Used and Types of Waste
Possibly Generated	104

Criteria Pollutant Emissions from Railway Maintenance, 1997	106

CO Emissions from Railway Maintenance, 1986-1997	106

VOC Emissions from Railway Maintenance,  1987-1997	107

PM10 Emissions from Railway Maintenance,  1986-1997	107
Pollutant Emissions from Line-.Jaul Operating Railroads (SIC 4011) Reported to
AIRS	:	
108
Number of Airports in the U.S., 1980-1997	112

Percent of Airports with Paved Runways, 1980-1997	114

Criteria Pollutant Emissions from Aircraft Manufacturing Facilities, 1990-1996
(short tons)	116

Criteria Pollutant Emissions from Aircraft Manufacturing Facilities by SIC Code,
1996	116

VOC Emissions from Solvent Utilization in Surface Coating for Aircraft (Point
and Area Sources), 1970-1997	117

VOC Emissions from Aircraft and Parts Manufac' -ing Facilities Reported to
AIRS	117

CO Emissions from Aircraft and Parts Manufac   ng Facilities Reported to AIRS	118

NO2 Emissions from Aircraft and Parts Manufacturing Facilities Reported to AIRS	118

S02 Emissions from Aircraft and Parts Manufacturing Facilities Reported to AIRS	118

PMio Emissions from Aircraft and Parts Manufacturing Facilities Reported to
AIRS	118

Wastes Associated with Airplane Manufacturing Processes	120

Toxic Chemicals Released from Aircraft-Related Manufacturing Facilities, 1996
(pounds per year	121

Top 5 TRI Releasing Facilities Reporting Only 372 SIC Codes to TRI, 1996	122

Toxic Chemicals (Core) Released from Aircraft-Related Manufacturing Facilities
(SIC 3721, 3724, 3728), 1988-1996 (thousands of pounds per year)	122
VI

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                                                                               LIST OF TABLES
Table 5-15:    Criteria Pollutant Emissions from Aircraft Travel, 1997	124

Table 5-16:, , CO Emissions from Aircraft, 1940-1997	125

Table 5-17:    NOx Emissions from Aircraft,  1940-1997	125

Table 5-18:    VOC Emissions from Aircraft, 1940-1997	126

Table 5-19:    S02 Emissions from Aircraft, 1940-1997	126

Table 5-20:    PM10 Emissions from Aircraft, 1940-1997	127

Table 5-21:    PM2.5 Emissions from Aircraft, 1990-1997	127

Table 5-22:    Lead Emissions from Aircraft,  1970-1997	128

Table 5-23:    Carbon Dioxide Emissions from Fossil Fuel Combustion in Air Travel (million
              metric tons of carbon)	129

Table 5-24:    Nitrous Oxide and Methane Emissions from Aircraft Travel, 1996	130

Table 5-25:    Population Exposed to DNL 65 dB from Aircraft	131

Table 5-26:    Population Exposed to 65 DNL at 30 Busiest Airports	132

Table 5-27:    Aviation Hazardous Materials Incident Totals, 1990-1997	133

Table 5-28:    Aviation Hazardous Materials Incidents, 1997	134

Table 5-29:    Collisions between Wildlife and Civil Aircraft in the U.S., 1991-1997	136

Table 5-30:    Criteria Pollutant Emissions from Airport, Flying Fields, and Terminals, 1990-
              1996 (short tons)	139

Table 5-31:    VOC Emissions from Airports  and Aviation Support Facilities reported to AIRS	139

Table 5-32:    CO Emissions from Airports and Aviation Support Facilities Reported to AIRS	139

Table 5-33:    NO2 Emissions from Airports and Aviation Support Facilities Reported to AIRS	140
                   J).Vf'': ". '; '
Table 5-34:    SO2 Emissions from Airports and Aviation Support Facilities Reported to AIRS	140

Table 5-35:    PMi0 Emissions from Airports  and Aviation Support Facilities Reported to AIRS	140

Table 5-36:    Criteria Pollutant Emissions from Airport Service Vehicles, 1997	140

Table 5-37:    CO Emissions from Airport Service Vehicles, 1940-1997	141

Table 5-38:    NOX Emissionsfrom Airport Service Vehicles, 1940-1997	141

Table 5-39:    VOC Emissions from Airport Service Vehicles,  1940-1997	142

Table 5-40:    PM10 Emissions from Airport Service Vehicles,  1940-1997	142
                                                                                          Vll

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INDICATORS OF THE ENVIRONMENTAL IMPACTS OF TRANSPORTATION
Table 6-1:     Quantities Dredged by the U.S. Army Corps of Engineers, 1990-1998	150

Table 6-2:     Disposal of Dredged by the U.S. Army Corps of Engineers, 1990-1998	150

Table 6-3:     Criteria Pollutant Emissions from Ship and Boat Building and Repairing Facilities,
              1990-1996 (short tons)	154

Table 6-4:     Criteria Pollutant Emissions from Ship and Boat Building and Repairing Facilities
              by SIC Code, 1996 (short tons)	154

Table 6-5:     VOC Emissions from Solvent Utilization in Manufacture of Large Ships (Point
              and Area Sources), 1940-1997	155

Table 6-6:     VOC Emissions from Vessel Manufacturing Facilities Reported to AIRS	155

Table 6-7:     CO Emissions from Vessel Manufacturing Facilities Reported to AIRS	156

Table 6-8:     NO2 Emissions from Vessel Manufacturing Facilities Reported to AIRS	156

Table 6-9:     S02 Emissions from Vessel Manufacturing Facilities Reported to AIRS	156

Table 6-10:    PM10 Emissions from Vessel Manufacturing Facilities Reported to AIRS	156

Table 6-11:    Wastes Associated with Ship and Boat Manufacturing Processes	157

Table 6-12:    Toxic Chemicals Released from Ship- and Boat-Building & Repairing Facilities,
              1996 (pounds per year)	158

Table 6-13:    Toxic Chemicals (Core) Released from Ship- and Boat-Building & Repairing
              Facilities, SIC 3731, 3732), 1988-1996 (thousands of pounds per year)	159

Table 6-14:    Criteria Pollutant Emissions from Marine Vessel Travel, 1997	161

Table 6-15:    CO Emissions from Ships and Boats, 1940-1997	162

Table 6-16:    NOx Emissions from Ships and Boats, 1940-1997	162

Table 6-17:    VOC Emissions from Ships and Boats, 1940-1997	163

Table 6-18:    SO2 Emissions from Ships and Boats, 1940-1997	163

Table 6-19:    PM10 Emissions from Ships and Boats, 1940-1997	164

Table 6-20:    PM2.5 Emissions from Ships and Boats, 1940-1997	164

Table 6-21:    Carbon Dioxide Emissions from Fossil Fuel Combustion in Water-borne Travel
              (million metric tons of carbon)	165

Table 6-22:    Nitrous Oxide and Methane Emissions from Water-borne Travel, 1996	166

Table 6-23:    Oil Spills in U.S. Navigable Waters from Vessel Incidents (Number of Incidents
              and Volume, in thousands of gallons), 1982-1996	169
via

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                                                                              LIST OF TABLES
Table 6-24:    Maritime Hazardous Materials Incident Totals, 1990-1997	169




Table 6-25:... Maritime Hazardous Materials Incident Totals, 1997	170




Table 6-26:    Estimated Annual Garbage Generation by U.S. Maritime Sectors	174




Table 6-27:    VOC Emissions from Marine Facilities Reported to AIRS	176




Table 6-28:    CO Emissions from Marine Facilities Reported to AIRS	176




Table 6-29:    NO2 Emissions from Marine Facilities Reported to AIRS	176




Table 6-30:    SO2 Emissions from Marine Facilities Reported to AIRS	176




Table 6-31:    PMi0 Emissions from Marine Facilities Reported to AIRS	177




Table 6-32:    Wastes Associated with Marine Vessel Terminal  Operations	177




Table 7-1:     Summary of Major Environment-Focused Databases and Publications	182
                                                                                          IX

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INDICATORS OF THE ENVIRONMENTAL IMPACTS OF TRANSPORTATION

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                                 LIST OF FIGURES
Figure 1-1:    Effects of Transportation and Related Activities on the Environment	8

Figure 2-1:    Share of CO Emissions from Transportation, 1997	12

Figure 2-2:    CO Emissions from Travel,  1970-1997	13

Figure 2-3:    Share of VOC Emissions from Transportation, 1997	13

Figure 2-4:    Share of NOx Emissions from Transportation, 1997	13

Figure 2-5:    VOC and NOx Emissions from Travel, 1970-1997	14

Figure 2-6:    Lead Emissions from Travel, 1970-1997	14

Figure 2-7:    Share of PMio Emissions from Transportation, 1997	15

Figure 2-8:    Share of PM2.s Emissions from Transportation, 1997	15

Figure 2-9:    Share of S02 Emissions from Transportation, 1997	16

Figure 2-10:   Transportation Emissions, 1970-1997	16

Figure 2-11:   Travel and Criteria Pollutant Emissions by Mode of Travel	17

Figure 2-12:   Percent of Point Source Emissions from Transportation Vehicle and Equipment
             Manufacturing, 1997	18

Figure 2-13:   Criteria Pollutant Emissions from Transportation Vehicle and Equipment
             Manufacturing, 1996	18

Figure 2-14:   Mobile Source Contribution to HAP Inventories	19

Figure 2-15:   Share of C02 Emissions from Transportation, 1997	21

Figure 2-16:   Share of CH4 Emissions from Transportation, 1997	23

Figure 2-17:   Share'offtOj Emissions from Transportation, 1997	23

Figure 2-18:   Estimated U.S. Emissions of CFC-12 and HFC-134a, 1990-1997	24

Figure 2-19:   Disposal/Use of Material Dredged by U.S. Army Corps of Engineers, 1998	25

Figure 2-20:   Sources of Recent Wetland Loss	26

Figure 2-21:   Number of Reported Strikes between Wildlife and Civil Aircraft	27

Figure 2-22:   Number of Animal Collisions with Motor Vehicles Reported to HSIS	27

Figure 2-23:   Number of Fuel Spills and Total Volume of Fuel Discharged Annually, 1982-1997	30
                                                                                         XI

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INDICATORS OF THE ENVIRONMENTAL IMPACTS OF TRANSPORTATION
Figure 2-24:   Number of Hazardous Materials Incidents, 1990-1997	31

Figure 2-25:   U.S. Population Exposed to DNL of 65 dB or Greater from Aircraft	32

Figure 2-26:   Number of Motor Vehicles Scrapped Annually (thousands), 1970-1995	33

Figure 3-1:     VOC Emissions from Solvent Utilization in Surface Coating for Autos & Light
              Trucks (Point and Area Sources), 1970-1997	47

Figure 3-2:     VOC Emissions from On-Road Vehicles	51

Figure 3-3:     NOX Emissions from On-Road Vehicles	52

Figure 3-4:     CO Emissions from On-Road Vehicles	53

Figure 3-5:     PM10 Emissions from On-Road Vehicles	54

Figure 3-6:     PM2.5 Emissions from On-Road Vehicles....	55

Figure 3-7:     S02 Emissions from On-Road Vehicles	56

Figure 3-8:     Pb Emissions from On-Road Vehicles	57

Figure 3-9:     Change in Criteria Pollutant Emissions Compared to Vehicle Travel, 1940-1997	58

Figure 3-10:   PM|0 Fugitive Dust Emissions	59

Figure 3-11:   C02 Emissions from Motor Vehicles	61

Figure 3-12:   N2O Emissions from Motor Vehicles	62

Figure 3-13:   CH4 Er.  uons from Motor Vehicles	62

Figure 3-14:   Highwa   Hazardous Materials Incidents, 1990-1997	67

Figure 3-15:   Animal Collisions with Motor Vehicles	70

Figure 3-16:   Highway Salt Sales	73

Figure 3-17:   Uses of Salt in tte/U.S., 1996	73

Figure 3-18:   VOC Emissions from Service Stations	76

Figure 3-19:   Disposal of Used Oil, 1991	80

Figure 3-20:   Disposition of Scrap Tires, 1995	81

Figure 4-1:     VOC Emissions from Solvent Utilization in Surface Coating for Rail Equipment	91

Figure 4-2:     CO Emissions from Railroad Operations	96

Figure 4-3:     NOX Emissions from Railroad Operations	96
xn

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                                                                            LIST OF FIGURES
Figure 4-4:    VOC Emissions from Railroad Operations	97

Figure 4-5: ..._ SO2 Emissions from Railroad Operations	97


Figure 4-6:    PM,0 Emissions from Railroad Operations	98


Figure 4-7:    PM2.5 Emissions from Railroad Operations	98

Figure 4-8:    CO2 Emissions from Railroads	99


Figure 4-9:    Railroad Hazardous Materials Incidents, 1990-1997	102

Figure 4-10:    CO Emissions from Railway Maintenance	106

Figure 4-11:    VOC Emissions from Railway Maintenance	107

Figure 4-12:    PM(0 Emissions from Railway Maintenance	107

Figure 5-1:    VOC Emissions from Solvent Utilization in Surface Coating for Aircraft	117

Figure 5-2:    CO Emissions from Aircraft	125


Figure 5-3:    NOX Emissions from Aircraft	125

Figure 5-4:    VOC Emissions from Aircraft	126

Figure 5-5:    S02 Emissions from Aircraft	126

Figure 5-6:    PM|0 Emissions from Aircraft	127

Figure 5-7:    PM25 Emissions from Aircraft	127

Figure 5-8:    Pb Emissions from Aircraft	128

Figure 5-9:    Population Exposed to DNL 65 dB from Aircraft	131

Figure 5-10:    Aviation Hazardous Materials Incidents, 1990-1997	134


Figure 5-11:    Number of Reported Strikes between Wildlife and Civil Aircraft	136
                  _it*v.'i •
Figure 5-12:    CO Emissions from Airport Service Vehicles	141


Figure 5-13:    NOX Emissions from Airport Service Vehicles	141

Figure 5-14:    VOC Emissions from Airport Service Vehicles	142

Figure 5-15:    PM,0 Emissions from Airport Service Vehicles	142

Figure 6-1:    Disposal/Use of Material Dredged by Army Corps of Engineers, 1998	151


Figure 6-2:    VOC Emissions from Solvent Utilization in Manufacture of Large Ships	155

Figure 6-3:    CO Emissions from Ships and Boats	162
                                                                                         xiii

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INDICATORS OF THE ENVIRONMENTAL IMPACTS OF TRANSPORTATION
Figure 6-4:    NOX Emissions from Ships and Boats	162




Figure 6-5:    VOC'.Emissions from Ships and Boats	163




Figure 6-6:    S02 Emissions from Ships and Boats	163




Figure 6-7:    PM10 Emissions from Ships and Boats	164




Figure 6-8:    PM2.5Emissions from Ships and Boats	164




Figure 6-9:    Maritime Hazardous Materials Incidents, 1990-1997	170
 xiv

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1. INTRODUCTION
1.1 BACKGROUND

Although the nation's transportation system provides a wide range of benefits, it also generates
unintended adverse impacts on environmental quality and human health. Since the late 1960s and early
1970s, increased recognition of environmental and health problems has led to significant policy actions
aimed at reducing these impacts. Legislation on clean air and water, protection of environmentally
sensitive habitats and species, noise control, and regulation of hazardous materials transportation, among
others, have been successful in addressing some transportation impacts.

This report discusses transportation's impacts on the natural environment and provides quantitative
estimates of those effects at a national level. It provides a comprehensive compilation of data on all of the
environmental implications of the transportation sector. The document addresses all primary modes of
transportation in environmental media and covers a wide range of transportation activities —
infrastructure construction, vehicle maintenance, travel, operations and maintenance, and disposal. This
document presents data that can be used as "indicators" of the magnitude of environmental problems
associated with transportation.

<9> PURPOSE
EPA intends this document to serve as a resource for transportation and environmental decisionmakers,
researchers, and the public. The report compiles statistical information from many environmental data
sources and identifies information that can be used to track environmental performance. EPA has three
goals for this document:

1) To describe the full range of environmental impacts associated with transportation;

2) To identify quantified national-level data on these impacts; and

3) To assess gaps in data and limitations of various indicators.

This is the second edition of EPA's compilation of environmental indicators for the transportation sector.
Since the first version of this report was completed in 1996, a large amount of new environmental
information has become available. Environmental databases have been updated, methodologies have been
revised, and new studies havebeen conducted. This document updates the environmental data and has
been restructured to improve the presentation and discussion of environmental indicators.

($ SCOPE OF STUDY
When people think about the environmental impacts of transportation, they often think about habitat loss
from road construction and air pollution from motor vehicle use. They often fail to consider other
environmental consequences associated with transportation, such as the impacts of vehicle manufacture
and supporting facilities. This study is unique in its attempt to quantify the full range of environmental
impacts caused by transportation. It examines the full range of environmental consequences associated
with four modes of transportation and for the transportation sector as a whole. The "life-cycle" of
transportation activities and facilities is examined, although some upstream and downstream effects are

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INDICATORS OF THE ENVIRONMENTAL IMPACTS OF TRANSPORTATION
not emphasized. This study attempts to address the full range of environmental issues associated with
transportation at a summary level.


MODES OF TRANSPORTATION

This report presents environmental information for four modes of transportation:

     *  Highway - The highway system includes road infrastructure, and on-road motor vehicles,
        including automobiles, light-duty trucks, buses, and freight trucks.

     *  Rail - The rail system includes intercity passenger rail (Amtrak), rail transit (light rail, heavy rail,
        and commuter rail), and freight rail.

     *  Aviation - The aviation system includes general and commercial aviation.

     »  Maritime - The n . • itime system includes water-borne freight, as well as passenger ferries and
        recreational boats.

In addition, this report compiles data on environmental impacts for the transportation sector as a whole,
and identifies the contribution of travel and transportation-related industries in comparison to other
sectors of the economy.
LIFE-CYCLE OF TRANSPORTATION ACTIVITIES
This report addresses the life-cycle of transportation activities and facilities:

     *  Infrastructure construction - Construction and development of transportation facilities, such as
        roadways, railways, airports, and navigation channels;
     »  Vehicle manufacture - Production of vehicles and parts (including motor vehicles, railcars and
        locomotives, aircraft, and ships and boats);

     *  Travel - Vehicle operations to transport people and goods;

     »  Operations, maintenance and support - Activities to support travel, such as application of
        deicing chemicals, as well as operation of facilities to support travel, such as gas stations, airport
        terminals, and marinas; and

     »  Disposal - Disposal or recycling of vehicles, parts, and facilities.

The upstream effects horn fuel processing, storage, and distribution are also discussed briefly.


ENVIRONMENTAL CONSEQUENCES
This report examines the effects of transportation on all environmental media — air, water, and land.
Because pollutant releases can have multi-media effects, this report generally presents environmental
information by pollutant.  It addresses:

     •  Criteria air pollutants —Pollutants that adversely affect human health and welfare: carbon
        monoxide (CO), ground level ozone (O3) and its precursors, lead (Pb), nitrogen dioxide (N02),
        paniculate matter (PM), and sulfur dioxide (SO:);

-------
                                                                                  INTRODUCTION
        Toxics — Pollutants that cause or may cause cancer or other serious problems, such as
        reproductive effects or birth defects, or adverse ecological effects;

        Greenhouse gases — Compounds that contribute to global climate change by trapping heat
        within the Earth's atmosphere: carbon dioxide, methane, nitrous oxide, and several other
        compounds;

        Chlorofluorocarbons and stratospheric ozone depletion — Man-made chemicals that are
        known to deplete stratospheric ozone;

        Habitat and land use — Adverse effects on wildlife, ecosystems, and endangered species such
        as habitat destruction or fragmentation;

        Water quality and aquatic resources — Adverse effects to the water quality in lakes, streams,
        rivers, or groundwater and the ecosystems that depend on them;

        Hazardous materials incidents — Releases of hazardous materials during transportation;

        Noise — Unwanted sounds that interfere with communication or cause adverse health effects;
        and

        Solid waste — Disposal of materials and parts through recycling, reuse, or shipment to landfills.
IMPACTS DE-EMPHASIZED OR EXCLUDED

We have limited the scope of this study to the direct impacts of transportation infrastructure and activities.
It does not address the full indirect, upstream, downstream, and historical impacts. Impacts de-
emphasized or excluded include:

     »  Certain long-run and cumulative impacts — For example, 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;

     »  Upstream impacts — Some examination of the manufacture of vehicles, but not raw inputs from
        the steel or chemical industries; limited evaluation of gasoline/oil refining;

     *  Downstream impacts — Some consideration of the disposal of tires, waste oil, and vehicles, but
        not a full analysis of all disposal impacts, such as wastes resulting from airport operations or
        industrial processes;

     »  Indirect impacts — No analysis of the effects associated with industrial or residential
        development that rn|y occur near new transportation facilities;

     »  Local impacts — No analysis of impacts in specific watersheds, urban areas, or regions;

     •  Cultural, aesthetic, and social impacts — No analysis of these impacts; and

     »  Resource depletion impacts — Nonrenewable resource depletion (e.g., use of fossil fuels by
        motor vehicles) is not addressed as a separate issue because it does not damage the environment
        per se.


<$ REPORT STRUCTURE
A number of changes have been made since the original  edition to improve the report's utility. They
reflect input from a panel of environmental experts from the U.S. Department of Transportation, U.S.

-------
INDICATORS OF THE ENVIRONMENTAL IMPACTS OF TRANSPORTATION
Department of Energy, and academic institutions who were asked to provide input on the organization of
the report.  They include:

     *  Morefocus-on national statistics that can serve as indicators — This report focuses solely on
        environmental data that reflect national impacts; local examples are not presented in this report.
        In addition, the report presents trend data where available to provide a measure of progress and
        direction.

     •  More focus on context — Context is important in determining how problematic environmental
        impacts are and how much progress is being made. For example, the  share of impacts from
        transportation sources affects how much importance should be placed on these effects (e.g., if a
        transportation source is a very small  share of total releases, we may assign less importance to
        controlling this source).  Exposure to pollution and resulting health and welfare impacts affect
        the importance of pollutant releases (e.g., if most areas of the nation attain air quality standards
        for lead, emissions of lead from aircraft may not be a significant health issue). Finally, when
        examining environmental impacts, it is important to be aware of the level of activity producing
        the effect (e.g., significant reductions in air pollutant emissions from motor vehicle travel are
        more striking given rapid increases in vehicle travel).

     *  More focus on data issues — The report includes a discussion of the  major databases and data
        sources available.  It highlights the limitations and weakness in these sources, as  well as gaps in
        environmental information.

     *  Compilation of the impacts of the entire transportation sector — The report includes a chapter
        that summarizes the full  transportation sector contribution to each environmental issue.  In the
        initial edition of this report, impacts were addressed only in separate chapters for each mode of
        transportation, which did not allow for easy review of the total impact of transportation or
        comparisons of modal impacts.  Although a number of reviewers suggested more modal
        comparisons, comparisons of effects per passenger mile or ton mile are not included in this
        report.1

This report is structured as follows:

Introduction
Chapter 1: Introduction — The report begins with a brief introduction to environmental indicators,
discusses the strengths and weaknesses of various types of indicators, and presents information on data
availability and limitations.

Transportation Environmental  Indicators
Chapter 2: Transportation Indicators Summary — This chapter is organized by environmental topic and
summarizes the contribution of transportation as a whole to each impact, as well as the contributions of
specific transportation sources (e.g., modes and sub-modes).
1 Effects per passenger mile or ton mile-may vary significantly in different places, by time of day, and by type
of trip. Also, the modes are not exact substitutes for each other, the levels of service on the modes differ and
the types of trips and types of freight carried by each mode differ. Given the level of effort required for this
compilation and distinct nature of the research, the U.S. Environmental Protection Agency will undertake a
separate research effort to develop such comparisons.

-------
INTRODUCTION
The report goes on to provide more detail on environmental impacts associated with each mode of
transportation. Each chapter presents a discussion of environmental effects and quantified indicators,
organized by type of transportation activity.

Chapter 3: Highway Indicators

Chapter 4: Rail Indicators

Chapter 5: Aviation Indicators

Chapter 6: Maritime Indicators

Data Issues

Chapter 7: Data Availability and Next Steps — This chapter identifies the major environmental databases
used to track the environmental impacts of transportation and develop the indicators presented in this
report. It also highlights data gaps and potential next steps.
1.2 DEFINITION OF INDICATORS

The term "indicator" is used throughout this report to refer to quantitative estimates of the magnitude or
severity of a problem or issue. Indicators may be based on measurements or modeling. National estimates
of environmental impacts are typically derived from modeling or other methods of extrapolation from
local or site-specific data.

($ WHAT INDICATORS CAN DO
Indicators can be extremely useful in guiding transportation and environmental policy discussions. They
can:

» Assess the magnitude of environmental problems — Indicators can highlight environmental
problems by providing information on the largest sources of environmental problems. By
identifying the full range of impacts, indicators can also provide a broad perspective on
environmental issues.
* Help set priorities — By identifying problems and the share of problems caused by specific
activities, indicators can help set priorities, particularly for research and among issues needing
new or improved policies.
* Develop performance measures and track progress toward environmental goals — Ideal
indicators can be tracked consistently and reliably tracked over time, and used to develop
measures of environmental performance and track progress toward meeting targets.
• Educate policymakers, transportation and environmental stakeholders, and the public — By
providing information on the contribution of transportation to environmental problems, indicators
can help inform the public about environmental issues in transportation.

® WHAT INDICATORS CANNOT DO
It is important to keep in mind that indicators can be misapplied so care should be taken to consider their
limitations. Briefly, indicators cannot serve the following purposes:

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INDICATORS OF THE ENVIRONMENTAL IMPACTS OF TRANSPORTATION
» 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 decreasing air emissions, but these could
result either from policy-driven per-mile emissions reductions or from reduced travel due to
recession or rising fuel prices.

» Provide an economic analysis - Indicators do not provide information about the benefits of
travel and related activities. For example, deicing salt application has significant environmental
impacts, but is beneficial in allowing travel and saving lives during storms. Indicators say
nothing about the costs or benefits of policies that might alleviate such environmental impacts.

* Define acceptable levels of impact or rates of progress - Indicators may describe objectively the
amount of impact or rate of progress, but subsequent policy decisions must be made about
whether a given impact or rate of progress is acceptable. Indicators of environmental impact
should not be used alone for setting priorities for regulatory action. Instead, cost-effectiveness of
policy options should be considered.

® TYPES OF INDICATORS
This report uses a three-stage framework for identifying environmental indicators:

* Outcomes

» Outputs

» Activities

These stages are shown in Figure 1-1. Transportation-related activities — infrastructure construction,
vehicle manufacture, travel, maintenance and support, and disposal — result in releases of pollutants or
damage to habitats. These outputs, in turn, have human health or welfare effects.

Indicators can be developed at each of these stages. Ultimately, people care about environmental
outcomes; however, because of data gaps and the difficulty associated with isolating transportation's share
of an impact from that of other sources, outcome indicators often are not available. Each type of indicator
is described below with a short synopsis of strengths and weaknesses and examples of indicators.

OUTCOME INDICATORS
Indicators of outcomes are rheasures of end results. They provide quantitative information on health,
environmental, and welfare effects resulting from transportation. Outcome indicators are desirable
because they provide information about the effects that people care about. Unfortunately, quantified
estimates of environmental outcomes are often unavailable or uncertain. Also, it is frequently difficult to
separate the effects of transportation from other sources. In practice, many outcome indicators are subject
to uncertainty or are qualitative in nature. For example, the number of states identifying highways as a
source of habitat loss could be considered an outcome indicator because it provides a sense of magnitude
about highway construction impacts on ecosystems. However, states may determine sources of habitat
loss differently and the indicator does, not say exactly how much habitat acreage has been lost. Other
examples of outcome indicators include:

» Number of wildlife deaths

-------
                                                                                   INTRODUCTION
        Changes in the abundance of species

        Number of cases of illness or mortality
OUTPUT INDICATORS

Output indicators provide information on the amount of releases, emissions, or incidents that are
associated with environmental damage, or the amount of land or resources consumed. They do not
quantify the actual damage that takes place, but provide information about outputs that are known to be
associated with human health, environmental, or welfare effects. Measurements, models, or other
methodologies are often available to estimate outputs consistently over time. Examples of outcome
indicators include:

     »  Quantity of pollution emitted or released

     »  Number of hazardous materials incidents

     *  Levels of noise
ACTIVITY INDICATORS
Activity indicators provide information about the extent of activities that are known to produce adverse
environmental effects. Activity data tend to be the most readily available of all indicators. Examples
include:

     *  Number of lane miles constructed

     *  Number of vehicles manufactured

     *  Number of vehicle miles traveled

     »  Quantity of deicing chemicals purchased (minus inventories)

While activity data are readily available, they are limited as environmental indicators because activities
do not always correspond directly to environmental harm. For example, all else equal, increasing vehicle
travel should produce greater quantities of pollutant emissions; however, motor vehicle emissions have
been declining since the 1970s despite significant increases in vehicle travel because emission control
technologies have improved. Likewise, a number of industries have significantly reduced pollutant
outputs through improved technologies and pollution prevention.

-------
Figure 1-1. Effects of Transportation and Related Activities on the Environment



UNRELATED k
ACTIVITIES 1

INFRASTRUCTURE
CONSTRUCTION
VEHICLE AND PARTS
MANUFACTURE
TRAVEL
OPERATIONS,
MAINTENANCE
AND SUPPORT
DISPOSAL OF
VEHICLES
AND PARTS


ACTIVITIES

f*
t •.
• *
1 /
• fe

•'* ' '?' ' 	 ' '
LAND USE CHANGES
- Land area taken
- Changes in impervious
surfaces
EMISSIONS/RELEASES TO
AIR, WATER, OR LAND
- Criteria air pollutants
- Toxics
- Greenhouse gases
- Chlorofluorocarbons
HAZARDOUS MATERIALS
INCIDENTS
AMOUNT OF MATERIAL
ENTERING SOLID WASTE
STREAM


• ' ' t .
1
••.:~^-":t
AMBIENT LEVELS/ •
POLLUTANT •
' ' ^ CONCENTRATIONS | \
. t •..'•'• •'<.>..
- -. •'. T • */; ', • • '
• r' :' 7' *.--'•
v-^i^V- •;•'•"•: ^ '","',. '.' J"'5"
.' ;-:' •'*•"• r " ''. ' -• "* "
'*y?&r ^ ^T-' PUTPUTS • .
•. •' '0 ''»*•.'-!•" '. '*' ''".{ ..' •* ' " . '* '"•'•-'-• - ,; * . - ;
'"• ,:'v.;;-:^:!-.K!i-- ••^•p: :^' .•'•/ .•''"•" ' Yvfr^n^v?
' . ' " ' ' '• ' • ' ' "C* ' ' '*'•' • . ;
' ~ ' . C"*

EXPOSURE L.
':r"".*v';^'x:'1 :-.'
'"."- •'''*';-• "'••' ".' ''
.« •• * '
4 ' '
• . ' • v'
i
1 EFFECTS ON 1
* HABITAT, I
WILDLIFE, AND I
1 ECOSYSTEMS j
EFFECTS ON 1
HUMAN HEALTH I
^ AND WELFARE I
OUTCOMES

-------
INTRODUCTION
Q IDEAL INDICATORS OF TRANSPORTATION IMPACTS
An ideal indicator:

» Focus on end results — Information should be provided on outcomes, such as number
of illnesses caused, not outputs or activities that cause outcomes

» Isolate transportation's share of the impact — The indicator should identify the effect
of transportation rather than providing an estimate of environmental quality that may
depend on numerous sources

» Be reasonably certain — Although modeling may be necessary to estimate the national
effect, the indicator should be generally agreed upon as reasonably accurate and reliable

» Be stated in meaningful units — The indicator should be presented in units that allow
comparison to other sources of a problem or to a goal

In practice, there are tradeoffs between these traits. Although outcome indicators are the most
desirable type of environmental information, data on environmental outcomes is typically not
available or tracked consistently. When outcome measures are available, it is often impossible to
identify the contribution of transportation separately from other sources. For example, one
measure of outcomes for air quality is the number of people living in areas that do not meet one
or more of the national ambient air quality standards (NAAQS). However, even if we know how
many people are exposed to poor air quality, this figure does not tell us about the contribution of
transportation to the problem. The estimation of health and welfare effects, such as the number of
cases of respiratory problems associated with transportation-related pollution, can also be the
subject of significant debate.

In general, the best available indicators of transportation's impact tend to be output indicators —
measures of the quantity of pollution emitted or released, or the number of incidents known to
cause environmental damage. Estimates of outputs tend to be estimated, reported, or tracked more
consistently than outcome measures. As a result, this report focuses primarily on output
indicators. It is important, however, to keep end results in mind when examining output
indicators. Not all emissions or releases are equal; health and environmental results depend on
exposure to pollution and other factors, such as the location and time of releases. In this report,
activity indicators are presented when output data are unavailable.
1.3 PRESENTATION OF ENVIRONMENTAL INDICATORS

The following sections of this report present information on the environmental consequences
associated with four modes of transportation: highways, rail, aviation, and maritime transport. A
summary chapter highlights the effects of transportation on the environment and the relative
magnitude of impacts from each mode. Individual chapters for each mode follow the summary
chapter. In the modal chapters, subsections focus on the effects of each transportation activity —
infrastructure construction;-vehicle manufacture; travel; operations, maintenance, and support;
and disposal.

-------
INDICATORS OF THE ENVIRONMENTAL IMPACTS OF TRANSPORTATION
Each environmental impact is presented with:

     »  Description of Impact — A brief discussion of environmental effects relating to
        transportation activities. The focus here is on processes that cause environmental outputs
        (generally, emissions, releases, or incidents), not on why the outputs are harmful (e.g., a
        brief discussion of sources of air pollutant emissions from aviation travel, not how
        different air pollutants affect health and welfare). An overview of each pollutant and the
        contribution of transportation is provided in the summary chapter at the end of this
        report.

     *  Impact Factors — A list of some of the primary factors that affect the  magnitude of
        environmental impact.
     »  Indicators of Environmental Impact — The key indicators that have been quantified are
        presented. Because of data availability, output indicators predominate.  Outcome
        indicators are presented when available; activity measures are presented when output
        information is not available.
10

-------
2. TRANSPORTATION INDICATORS SUMMARY
This chapter summarizes national indicators of the environmental impacts of transportation.
Transportation is defined broadly here to include transportation infrastructure construction and
travel on the nation's transportation system, as well as related activities, such as transportation
equipment manufacturing, infrastructure maintenance, and vehicle support. This chapter identifies
the contribution of the transportation sector as a whole to specific environmental problems.
Quantitative indicators and trends are presented, as available.

The availability of data for tracking the environmental impacts of transportation varies greatly for
different aspects of the environment and types of transportation activities. Air pollution and
greenhouse gases from travel are among the most well understood impacts of transportation, and
estimates of emissions from travel have been quantified by mode. Many other environmental
effects, such as the impacts of transportation systems on habitat fragmentation and water quality,
have not been fully quantified nationally. In most cases, impacts associated with activities such as
transportation equipment manufacturing and facility maintenance have not been tracked
consistently or aggregated to the national level.

In this chapter, indicators are presented on nine environmental topics:

* Criteria air pollutants;
• Toxics;
» Greenhouse gases;
* Chlorofluorocarbons and stratospheric ozone depletion;
* Habitat and land use;
* Water quality;
* Hazardous materials incidents;
» Noise; and
» Solid waste.

This chapter compares the relative contribution of different transportation sources, modes, and
activities to each of these environmental issues. The chapters following this one provide more
detail on each mode., of. transportation: highway, rail, aviation, and maritime.
2.1 CRITERIA AIR POLLUTANTS

Criteria pollutants are those for which the U.S. Environmental Protection Agency (EPA) has
established National Ambient Air Quality Standards (NAAQS) to protect public health and
welfare. There are seven criteria pollutants with primary standards: ozone (O3), carbon monoxide
(CO), nitrogen dioxide (NO2), sulfur dioxide (SO2), lead (Pb), paniculate matter with
11

-------
INDICATORS OF THE ENVIRONMENTAL IMPACTS OF TRANSPORTATION
aerodynamic diameter less than or equal to 10 micrometers (PMio), and paniculate matter with
aerodynamic diameter less than or equal to 2.5 micrometers (PMi.s).1 Health effects of these
pollutants vary but include respiratory and cardiopulmonary problems, headaches, reduced
learning ability, and premature mortality. These pollutants also contribute to acid rain, reduced
agricultural yields, harm to vegetation, damage to building materials, and decreased visibility.

The effect of motor vehicles on air quality is one of the most recognized environmental
implications of transportation. Recognizing the magnitude of the problem, regulations under the
Clean Air Act and Amendments have dramatically reduced motor vehicle emissions of major
criteria pollutants. The U.S. Environmental Protection Agency tracks air quality trends through an
extensive monitoring network and maintains a program to estimate and track emission trends.
Emission estimates provide an indication of how much pollution is being released by different
types of sources, while monitored air quality data provide an indication of the severity of an air
quality problem.

Monitoring data from across the U.S. show dramatic decreases in air pollutant concentrations
since the early 1970s. Between 1978 and 1997, concentrations of ozone (one-hour) have fallen
by 30 percent, carbon monoxide concentrations have fallen by 60 percent, and lead concentration
have fallen by 97 percent. Between 1988 and 1997, the total number of days exceeding air quality
standards has dropped 56 percent in Southern California and 66 percent in the rest of the United
States.2 These dramatic improvements in air quality have been due in part to significant
reductions in transportation-related emissions, as presented below. Still, air pollution problems
remain through large parts of the country, and transportation remains a significant contributor to
this problem.
EMISSIONS FROM TRAVEL
Transportation contributes to air pollution primarily through the release of pollutants during the
fuel combustion process. Pollutants are also emitted during the refining and processing of fuels
and fuel evaporation. Transportation
sources consumed about 66 percent of Fi9ure 2'1: Share of co Emissions from Transportation, 1997
the petroleum used in the U.S. in 1997.3
Carbon Monoxide
Combustion of fuel during travel is a
major source of carbon monoxide (CO)
emissions, contributing about 6.1. percent
of all CO emissions nationwi3evMotor
vehicles are the primary transportation
source of CO emissions, contributing
about 94 percent of travel emissions.
Recreational boat*, 3%
Aircraft. 2%
Heavy duty motor vehicles
9%
Light duty motor vehicles
85%
Source: U.S. Environmental Protection Agency. National Air
Pollutant Emission Trends, 1900-1997.
1 The new PM,0 and ozone standards areon hold under court order as of the date of publication of this
report.
U.S. Environmental Protection Agency. National Air Quality and Emission Trends Report, 1997.
pp. 9,63.
U.S. Department of Energy. Transportation Energy Data Book: Edition 18. Table 2.5.
12

-------
SUMMARY
Figure 2-2: CO Emissions from Travel, 1970-1997
Carbon monoxide has become less of a national air quality problem over the past twenty years as
CO concentrations in the air have decreased by 60 percent nationwide. In 1997, only three
counties (Los Angeles County, CA; Fairbanks, AK; and Imperial County, CA) had monitoring
sites that faikd to meet the NAAQS for CO. Declining transportation emissions have contributed
significantly to the reduction in total CO
emissions. Carbon monoxide emissions from
transportation fell by 41 percent between 1970
and 1997. compared to an 11 percent reduction
in emissions from non-transportation sources
over this time period. Contributors to reduced
CO emissions from motor vehicles include
national standards for tailpipe emissions, new
vehicle technologies, and use of oxygenated
gasoline.
Although exceedances of the CO standard have
fallen significantly, high concentrations of CO
often occur in areas with heavy traffic
congestion. In cities, as much as 95 percent of
all CO emissions may come from on-road
vehicles.
100,000
M
O 80.000
60,000
C 40,000
(0
(A
O 20,000
1
fS R
OJ O>
8
Source: U.S. Environmental Protection Agency.
National Air Pollutant Emission Trends, 1900-1997.
Ozone and its Precursors
Ground level ozone (O-i) is the most
pervasive air pollution problem in the U.S.
Despite a 30 percent drop in one-hour
ozone concentrations in the air between
1978 and 1997, about 47.9 million
Americans lived in 77 counties with ozone
concentrations above the pre-existing
NAAQS in 1997. About 101.6 million
Americans lived in counties with ozone
concentrations above the level of the new
eight-hour ozone NAAQS.
Figure 2-3: Share of VOC Emissions from Transportation, 1997
Solvent use In vehicle
manufacturing/refinlshlng Service
2% \ station*
4%
Recreational boat*. SX
rrtght ship*. |%
Heavy duty motor vehicles
8%
Ught duty motor vehicles
79%
Source: U.S. Environmental Protection Agency. National Air
Pollutant Emission Trends, 1900-1997.
Ozone is formed in the atmosphere
through the reaction^of volatile organic Figure 2-4: Share of NOx Emissions from Transportation, 1997
compounds (VOCs) and oxides of
nitrogen (NOx) in the presence of heat and
sunlight. Ozone and these precursor
pollutants can be transported by prevailing
weather patterns to an area hundreds of
miles away from pollution sources.
Transportation is a major source of the
volatile organic compounds'and oxides of
nitrogen that contribute to ozone formation.
Transportation sources emitted 31 percent
of VOCs and 36 percent of NOX in 1997, as
Recreational boats, 1%
Freight ships, 3%
Aircraft, 2%
flail, n%
Heavy duty motor vehldee
26%
Ught duty motor vehicles
5T%
Source: U.S. Environmental Protection Agency. National Air
Pollutant Emission Trends, 1900-1997.
13

-------
INDICATORS OF THE ENVIRONMENTAL IMPACTS OF TRANSPORTATION
Figure 2-5: VOC and NOX Emissions from Travel,
1970-1997
16,000
shown in Figures 2-3 and 2-4. VOCs are
emitted both from fuel combustion and
fuel evaporation. Service stations and
solvent use in vehicle manufacturing and
refmishing also emitted significant
amounts of VOCs. Diesel vehicles emit
NOX at much higher rates than gasoline
vehicles; as a result, heavy-duty motor
vehicles and rail are much larger
contributors to NOx emissions than to
emissions of VOCs.

Significant progress has been made in
reducing VOC emissions from
transportation, and VOC emissions from
transportation sources have dropped 56
percent between 1970 and 1997, in
comparison to a 24 percent reduction from non-transportation sources. Most of the tonnage
reduction has come from light-duty motor vehicles.

In contrast, NO\ emissions have proven more difficult to control. Nationally, N0\ emissions
increased by about 11 percent between 1970 and 1997. NOX emissions from transportation
increased 5 percent over this time period. Most of the increase in NOx from transportation came
from non-road sources, like rail, aviation, and maritime transport. NOx emissions from motor
vehicles actually dropped 5 percent between 1970 and 1997, despite a 127 percent increase in
vehicle miles traveled.
8
Source: U.S. Environmental Protection Agency. National Air
Pollutant Emission Trends, 1900-1997.
Figure 2-6: Lead Emissions from Travel,
1970-1997
Lead
In the early 1970s, automobiles were the
major contributors of lead (Pb) emissions to
the atmosphere. As a result of EPA's
regulatory efforts to remove lead from
gasoline, transportation sector emissions of
lead have declined dramatically, leading to
the virtual elimination of lead as an ambient
air quality problem. Concentrations of lead in
the air decreased by 97 percent between 1978
and 1997, with total emissions of lead down
98 percent between 1970 and 1997.

Today, metals processing is the major source
of lead emissions and the highest ambient air
concentrations of lead are found near ferrous
and nonferrous smelters, battery
manufacturers, and other stationary sources.
Aviation is now the only major source of lead emissions from the transportation sector. Because
industrial processes are now responsible for all violations of the lead standard, EPA's lead
monitoring now focuses on these point sources.
240,000

200,000

M 160.000
§
~ 120,000
o
« 80.000

40,000
Source: U.S. Environmental Protection Agency. National
Air Pollutant Emission Trends, 1900-1997.
14

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                                                                                  SUMMARY
Paniculate Matter
Paniculate matter is the term used to describe a mixture of solid particles and liquid droplets
found in the air. These particles vary widely in size and can remain suspended in the air for
extended periods. EPA has established a National Ambient Air Quality Standard (NAAQS) for
both coarse particles under 10 microns in diameter (PMio) and fine particles under 2.5 microns in
diameter (PM2.5). Fine particles are thought to be most harmful to human health because their
small size allows them to penetrate the lungs, resulting in decreased lung function, increased
respiratory symptoms and disease, and premature death. PM is also the major cause of reduced
visibility in parts of the U.S., and can adversely affect plants, animals, and materials. PM can be
emitted directly or formed in the atmosphere as a result of reactions of SOX, NOx, and other
§ases-                              Figure 2-7: Share of PMio Emissions from Transportation, 1997
                                                                           RccrwtlOfUl boats, 6%
                                                                           Frtt^ht ship*. e%

                                                                           Aircraft, 10%
                                                                           Rail, 7%
                                                                           HMvy duty motor vtMdM
                                                                           41%
                                                                           Light duty motor vthlckw
                                                                           26%
                                    Source: U.S. Environmental Protection Agency. National Air
                                    Pollutant Emission Trends, 1900-1997.
                                    Figure 2-8: Share of PM2.s Emissions from Transportation, 1997
Most particulate matter emissions
come from sources that are not
traditionally inventoried, such as
wind erosion, fugitive dust from
paved and unpaved roads, and
agriculture. Travel contributes
more toward fine PM (PM2.s) than
to PMio, but still makes up just
about 4 percent of PM2.5 emissions
nationally, as shown in Figures 2-
7 and 2-8.

Particulate matter emissions tend
to be associated most with diesel
engines, so heavy-duty motor
vehicles are the largest source of
transportation-related PM
emissions. In contrast to their
share of most other pollutants,
light-duty motor vehicles make up
a relatively small portion of
transportation emissions.

Direct emissions of PMio from the
transportation sector declined by
26% between 1970 aijd 1997.
Emissions from non-
transportation sources have fallen
due to controls on industrial
sources and construction
activities, as well as measures to reduce street dust emissions, including the use of clean anti-skid
materials like washed sand, better control of the amount of material used, and removal of material
from roads as soon as ice and snow melt.
                                               Pivcd
                                              RoKiDutt
                                                8%
RKTHtlonal boiu, 9%
Freight »hlp», 7%
Aircraft, 9%
Rail, 8%
                                                                           Hnvy duty motor vahteta
                                                                           46%
                                                                           Light duty motor vehicle*
                                                                           21%
                                    Source: U.S. Environmental Protection Agency. National Air
                                    Pollutant Emission Trends, 1900-1997.
                                                                                         15

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INDICATORS OF .THE ENVIRONMENTAL IMPACTS OF TRANSPORTATION
Sulfur Dioxide
Sulfur dioxide (SO:) is a less pervasive air quality problem nationwide compared to carbon
monoxide, ozone, and paniculate matter. Over the period 1978 to 1997, concentrations of SO2 in
the air declined by 55 percent. Fewer than 100,000 Americans lived in counties with air quality
concentrations above the level of the SO: NAAQS in 1997. Despite the small number of
exceedances of the SO: standard, sulfur dioxide emissions remains an environmental problem.
SO: contributes to paniculate matter in
the atmosphere and acid rain.
Figure 2-9: Share of SO; Emissions from Transportation, 1997
Light duty motor vthtclo*
33%
Source: U.S. Environmental Protection Agency. National Air
Pollutant Emission Trends, 1900-1997 and NET Viewer.
Transportation is a relatively minor J""°"um "•"«""/ ^H "'•""" •-"•••
source of SO: emissions, contributing
about 3 percent of total SO: emissions
nationwide. Production and refining of -^^^^ "-"-" ^•"•". <«.
petroleum for transportation also \ / \ g^,%9HM*'d>"vmoi°r>*hici<>
contributes about 2 percent of national
SO: emissions. SO: is formed when fuel
containing sulfur — mainly coal and oil
— is burned and during metal smelting
and other industrial processes. The highest
monitored concentrations of SO: are
recorded in the vicinity of large industrial
facilities. In contrast to industrial sources, SO: emissions from transportation have trended
upward through the 1970s and 1980s, largely due to increases in emissions by ships and boats. A
substantial decline in heavy-duty vehicle emissions occurred, however, between 1992 to 1994.
EPA recently promulgated a new
rule that requires significantly
lower sulfur content for gasoline,
which in turn will help to reduce
motor vehicles emissions of
VOCs, CO, and NOX since sulfur
in gasoline inhibits the
performance of the catalyst on
advanced technology vehicles.
Comparative Trends
Trends in transportation ....:
emissions, 1970-1997, are shcjwh
in Figure 2-10. As described
above, there has been significant
progress in reducing
transportation emissions of air
pollutants since the early 1970s.
2.00
Fiaure 2-10: Transportation Emissions. 1970-1997
0.00
O (N t CO 00
O> O5 O5 O5 O)
CM •* U3
O> O) O>
O5 O O>
Source: U.S. Environmental Protection Agency. National Air
Pollutant Emission Trends, 1900-1997.
4 Petroleum production and refining emissions were estimated based on SIC codes 1311 (Crude Petroleum
and Natural Gas), 1381 (Drilling Oil and Gas Wells), 1382 (Oil and Gas Field Exploration Services), 1389
(Oil and Gas Field Services, NEC), and 2911 (Petroleum Refining) (Source: U.S. Environmental Protection
Agency. NET Viewer). This figure was then multiplied by 66.2%, the percent of petroleum used for
transportation (Source: U.S. Department of Energy. Transportation Energy Data Book: Edition 18).
16

-------
SUMMARY
Transportation emissions have decreased substantially for three of the major pollutants emitted by
transportation sources: CO, VOC, and lead. Transportation-related emissions of NOX have risen
slightly, but most of this increase has been from non-road sources. Motor vehicle emissions of
NOK have actually fallen 5 percent between 1970 and 1997, despite a 127 percent increase in
vehicle miles traveled.

The contribution of emissions from different transportation sources varies significantly by
pollutant, as shown in Figure 2-11. Light-duty on-road vehicles emit the most CO, NOX, and
VOC emissions of any mode of transportation. Light duty vehicles are used for the vast majority
of all vehicle miles of travel and passenger miles of travel. Heavy-duty motor vehicles contribute
a large portion of particulate matter emissions and NOx emissions, primarily because diesel
vehicles emit a much more of these pollutants than gasoline vehicles. Marine vessels are a major
source of sulfur dioxide. Aircraft are the main source of lead emissions from transportation since
the phase-out of leaded gasoline.

Figure 2-11: Travel and Criteria Pollutant Emissions by Mode of Travel, 1997
Highway
Rail
Source: Vehicle miles, passenger miles, ton-miles — U.S. Department of Transportation, Bureau of Transportation
Statistics. National Transportation Statistics 1998. Emissions — U.S. Environmental Protection Agency. National
Air Pollutant Emission Trends, 1900-1997. Travel Statistics are for 1996 and emissions estimates are for 1997.
Vehicle miles and passenger miles do include recreational marine vessels. Ton miles figure is for domestic freight
and assumes all on road transport is by heavy duty vehicles.

EMISSIONS FROM VEHICLE MANUFACTURE, MAINTENANCE, AND SUPPORT
In addition to emissions from travel, criteria pollutant emissions are released from transportation-
related activities, including vehicle manufacture and maintenance and support operations. These
activities release a very small portion of total criteria pollutant emissions with the exception of
VOCs, as shown in Figure 2-12.
17

-------
INDICATORS OF THE ENVIRONMENTAL IMPACTS OF TRANSPORTATION
Figure 2-12: Percent of Point Source Emissions from
Transportation Vehicle and Equipment Manufacturing, 1996
Figure 2-13 compares the contribution
of different types of transportation
manufacturing facilities to air
pollutant emissions.and to the number
of establishments and value of
shipments by industry. The motor
vehicle and equipment manufacturing
industry is by far the largest
transportation-related manufacturing
industry, and is responsible for about
half of all transportation
manufacturing establishments and
two-thirds of the value of shipments.
It is also responsible for the majority
of emissions from transportation-
related manufacturing industries.
Criteria pollutants are also released
from aviation ground support
equipment and in the maintenance and support of the transportation system.
voc
CO
S02
PM-10
Source: U.S. Environmental Protection Agency. NET Viewer.
100%
Figure 2-13: Criteria Pollutant Emissions from Transportation Vehicle and Equipment
Manufacturing, 1996
^ Ship and boat building and repairing
LJ Aircraft and parts
| Railroad equipment
ffl Motor vehicles and equipment

Note: Number of establishments and value
of shipments based on 1992 data;
emissions effects estimated for 1996.
Sources: Establishments and Value of Shipments — U.S. Bureau of the Census. 7992 Census of Manufacturers.
Emissions — U.S. Environmental Protection Agency. NET Viewer.
18

-------
SUMMARY
2.2 TOXICS

Hazardous air pollutants (HAPs), commonly referred to as air toxics or toxic air pollutants, are
known or suspected to cause cancer or other serious human health effects or ecosystem damage.
Section 112 of the Clean Air Act now lists 188 pollutants or chemical groups as hazardous air
pollutants and targets sources emitting them for regulation. Compared to the criteria pollutants,
less information is available concerning potential health and environmental effects of HAPs.
Toxic air pollutants are known, however, to have a variety of environmental effects, including the
potential for some HAPs
to damage aquatic Figure 2-14: Mobile Source Contribution to HAP Inventories
ecosystems.
National Total HAP Emissions
based on 1993 NTI
National Emissions of
30 Draft Urban Area HAPs, 1990
Mobile Sources
21%
Mobile Sources
40%
Source: U.S. Environmental Protection Agency. National Air Quality and
Emissions Trends Report, 1997. pp. 69-79.
According to EPA's 1993
National Toxics
Inventory (NTI), mobile
sources released
approximately 21 percent
of hazardous air
pollutants out of 8.1
million tons of air toxics
released nationwide.
Recognizing that not all
toxics are national
problems, EPA has also
compiled an interim 1990 emission inventory for 30 proposed urban HAPs associated with area
sources. Of these HAPs that pose the greatest threat to public health in urban areas, about 40
percent of emissions came from mobile sources. Urban areas tend to have a higher proportion of
emissions coming from mobile sources than rural areas.

Toxics are also released from manufacturing facilities and are reported in the EPA's Toxic
Release Inventory (TRI). The transportation equipment industry (SIC Code 37) represents a small
share of TRI reported waste in comparison to its scope in the U.S. economy. In 1996, the
transportation equipment industry was responsible for 1.6 percent of waste but encompassed 8.5
percent of employment and 12.5 percent of the value of shipments among the industries reporting
to TRI.5

Over time, chemicals have been added to the TRI, deleted, or redefined. To enable comparison
between years, the T_a.lble2-l reports releases of chemicals required to be reported in all years,
called "core" chemicals.
5 U.S. Environmental Protection Agency, Office of Pollution Prevention and Toxics. 1996 Toxics Release Inventory
Public Data Release- 10 Years of-Right-to-Know: Industry Sector Analyses. December 1998 (Table 1-5).
19

-------
INDICATORS OF THE ENVIRONMENTAL IMPACTS OF TRANSPORTATION
Table 2-1: Core Toxic Chemicals Released from Transportation Manufacturing Facilities (Subset of
TRI Inventory) in thousands of pounds, 1988-19966
Year On-road vehicle
& equipment
manufacturing
(SIC 371, 375,
3792)
1988
1994
1995
1996
116,724
85,151
75,855
68,150
Rail equipment
manufacturing
(SIC 374)
2,210
1,906
1,561
1,425
Aircraft
manufacturing
(SIC 372)
40,270
1 1 ,297
9,577
7,181
Ship- and boat-
building and
repair (SIC 373)
17,966
13,826
14,869
14,149
Total
Transportation
174,960
110,274
100,301
89,480
Source: U.S. Environmental Protection Agency. Office of Pollution Prevention and Toxics. 1996 Toxics Release
Inventory Public Data Release - 10 Years ofRight-to-Know: Industry Sector Analyses. December 1998 (Table 14-3).

The majority of transportation industry toxic releases come from facilities involved in
manufacturing motor vehicles and car bodies (SIC code 3711) and motor vehicle parts and
accessories (SIC code 3714). Toxic chemicals may be released to the environment as air
emissions, surface water discharges, underground injection, or on-site land releases. The vast
majority of releases from transportation-related manufacture were releases to air, which include
stack emissions, equipment leaks, evaporative losses, and releases from building ventilation
systems.

Overall, the quantity of core toxic chemicals released from transportation-related manufacturing
facilities declined by over 50 percent between 1988 and 1996. On- and off-site releases of core
chemicals decreased from nearly 175 million pounds in 1988 to 89.5 million pounds in 1996.
Reductions in releases were due in part to source reduction, on-site waste management, and
tranfers off-site for waste management. One-fifth of firms submitting forms to TRI in the
transportation equipment sector (SIC Code 37) reported undertaking one or more source
reduction activities during 1996. Good operating practices and raw material and process
modifications were the two source reduction activities cited most often by the motor vehicles and
car bodies industry (SIC 3711) and the motor vehicle parts and accessories industry (3714) — the
two largest sources of waste. Aviation and motor vehicle industries had the highest percentage of
waste undergoing either on-site or off-site waste management. In 1996, within all transportation
manufacturing industries about 54 percent of toxics were recycled (chemicals were recovered and
made available for further use). Another 4 percent were used for energy recovery (combusted to
generate heat or energy) and 13 percent were destroyed through treatment.7
2.3 GREENHOUSE GASES

Greenhouse gases trap heat within the earth's atmosphere. While most greenhouse gases occur
naturally and serve to keep the planet hospitable to life, increasing concentrations of greenhouse
gases in the atmosphere threaten to alter the earth's climate dramatically. The world's most
6 The transportation manufacturing industry, as defined in this report, excludes a portion of the industries
that fall under SIC code 37 (Transportation Equipment). It excludes the following SIC codes: 3761 (Guided
Missiles & Space Vehicles), 3764 (Space Propulsion Units & Parts), 3769 (Space Vehicle Equipment, nee),
3795 (Tanks & Tank Components), and 3799 (Transportation Equipment, nee).
7 Calculated based on: U.S. Environmental Protection Agency, Office of Pollution Prevention and Toxics. 1996
Toxics Release Inventory Public Data Release - 10 Years ofRight-to-Know: Industry Sector Analyses. December 1998
(Table 14-9).
20

-------
SUMMARY
respected scientists agree that the threat of global climate change is real and that potential impacts
are significant, including extreme weather conditions, rising sea levels, and damage to agriculture
and ecosystems.

Transportation is a major contributor to emissions of carbon dioxide (CO2), the most important
greenhouse gas. Based on global wanning potential, CO2 accounts for about 84 percent of total
greenhouse gas emissions in the U.S. The remainder is made up of methane (9 percent), nitrous
oxide (5 percent), halocarbons, and other human-made gases, such as HFCs and PFCs (2
percent). Greenhouse gas emissions from transportation have been rising, in contrast to
emissions of other air pollutants, in large part because travel growth has outpaced improvements
in transportation energy efficiency. In particular, for motor vehicles — the largest source of
carbon dioxide emissions from transportation — vehicle fuel economy has been stagnant over the
past few years as more travel has shifted from automobiles to less efficient light trucks, including
pick-up trucks, sport utility vehicles, and minivans.

In the following discussion highlighting the percentage of total greenhouse gas emissions from
transportation, note that transportation sources are a subset of "mobile sources." As a result, the
share of emissions from travel is smaller than the share reported for mobile sources in national
greenhouse gas emission inventories compiled by the U.S. Department of Energy and U.S.
Environmental Protection Agency.9
Figure 2-15: Share of CO; Emissions from Transportation, 1997
CARBON DIOXIDE
Transportation sources emitted
approximately 31 percent of all
carbon dioxide emissions from fossil
fuel combustion in the U.S. in 1997.
In addition emissions from refining
petroleum in the United States for
transportation sector use
compromised about 5 percent of
total emissions. Not accounted for
are the emissions associated with
extracting crude oil (imports of
crude oil made up 42 percent of U.S.
petroleum consumption in 1997) and
refining oil that is imported as
refined petroleum (5 percent of U.S.
petroleum consumption in 1997).
Petroleum
Refining*
5%
Other, 3%
Recreational boats, 1%
Freight ships, 2%
Aviation, 14%
Rail, 2%

Heavy duty motor vehicles
16%
Light duty motor vehicles
62%
• Petroleum Refining estimate is for 1994
10
U.S. Environmental Protection Agency. Inventory of U.S. Greenhouse Gas
Emissions and Sinks: 1990-1997. March 1999 (draft) and U.S. Department
of Energy. Manufacturing Energy Consumption Survey, 1994.
8 U.S. Department of Energy, Energy Information Administration. Emissions of Greenhouse Gases in the
United States 1997. October 1998 (Table ES2).
9 Transportation sources do not include farm equipment, construction equipment, and utility equipment,
which are considered mobile sources. Note that recreational boating is included as a transportation source
in this report, even though it is not purely for a transportation purpose.
10 Percent of emissions from petroleum refining were calculated based on energy data for SIC code 2911
(Source: Manufacturing Energy Consumption Survey, 1994.); this figure was then multiplied by 66.2%, the
percent of petroleum used for transportation (Source: U.S. Department of Energy. Transportation Energy
Data Book: Edition 18). Other energy data reported come from U.S. Department of Energy. Transportation
Energy Data Book, 18th. Edition. Table 1.8.
21

-------
INDICATORS OF THE ENVIRONMENTAL IMPACTS OF TRANSPORTATION
Transportation sources emitted 460.4 million metric tons of carbon in 1997, out of a total of 1.48
billion metric tons of carbon from fossil fuel combustion." Most transportation emissions come
from on-road motor vehicles. About 78 percent of transportation emissions come from on-road
vehicles and approximately 14 percent come from aircraft, with the remainder from rail, ships,
boats, and other sources. Carbon dioxide emissions from travel have been growing rapidly, in
contrast with trends in other air emissions. Transportation emissions increased about 10 percent
between^l990 and 1997, growing from 419.1 million metric tons to 460.4 million metric tons of
carbon.12

In addition to direct release of C02 during fossil fuel combustion, CO2 and other greenhouse
gases are released from upstream fuels processing, distribution of fuels, vehicle assembly, and
facility maintenance. It is estimated that for gasoline light-duty vehicles CO2 emissions from
feedstock/fuel distribution and production equal approximately 25 to 30 percent of the amount of
CO: emitted from the vehicle, as shown in Table 2-2. Car assembly and materials emit another 16
percent of the amount emitted from the vehicle. In total, upstream processes emit another 41 to 46
percent of the CO2 emitted from the vehicle for light-duty gasoline vehicles and about 28 percent
of the CO2 emitted from the vehicle for heavy-duty diesel vehicles.

Table 2-2: Full Fuel Cycle CO; -equivalent Emissions for Light-duty Motor Vehicles (grams per mile)
Study Fuel Vehicle Peed/Fuel Car Total
Use distribution assembly Emissions
& production & materials
M.A. Delucchi,
Argonne National
Laboratory. 1991.
U.S. Department of
Energy. August 1996.
Conventional gasoline
Reformulated gasoline
Diesel fuel
Diesel fuel, heavy-duty
Gasoline
344.5
333.7
325.0
2,052.1
272.4 *
85.9
101.6
56.8
369.0
74.9*
55.9
55.9
42.1
206.0
•
486.3
491.2
423.9
2,627.1
347.3 *
"Only includes CO2 emissions: other estimates are for C02 equivalent emissions and consider CO2. CHL,, N2O, NOX.
CO. and NMOCs.
Sources: M.A. Delucchi, Argonne National Laboratory. "Emissions of Greenhouse Gases from the Use of
Transportation Fuels and Electricity." ANL/ESD/TM-22, Vol. 1. 1991 (Table 9).U.S. Department of Energy.
''Alternatives to Traditional Transportation Fuels 1994. Vol. 2: Greenhouse Gas Emissions." DOE/EIA-0585(94)/2,
August 1996 (Table 7).

Fossil fuels can also be used for producing products such as plastics, asphalt, or lubricants that
store carbon for long periods of time. Asphalt used in road construction, for example, stores
carbon. Fossil fuels used in the manufacture of materials like plastics for motor vehicles can also
store carbon if the material is not burned.
11 U.S. Environmental Protection Agency. "Inventory of U.S. Greenhouse Gas Emissions and Sinks: 1990-1997."
March 1999 (draft).
12 U.S. Department of Energy, Energy Information Administration. Emissions of Greenhouse Gases in the
United States 1997. October 1998. Table 10.
22

-------
SUMMARY
METHANE
Travel contributes less than one
percent of methane (CHO emissions
nationally,-with the majority of
emissions coming from landfills
and agriculture. Methane emissions
from transportation in 1997 were
estimated at 234,000 metric tons,
down about 11,000 metric tons
from 1990 levels. Nearly 95 percent
of transportation emissions of
methane come from on-road
vehicles, with the vast majority of
those from light-duty vehicles.
Aircraft emit approximately 3
percent of transportation methane
emissions, with smaller amounts from locomotives, ships, and boats.
Figure 2-16: Share of CH« Emissions from Transportation, 1997
Ships and boats, i%
Aviation. 3%
Rail, 1%
Heavy duty motor vthlclas
12%
Light duty motor vihlclts
83%
U.S. Environmental Protection Agency. "Inventory of U.S. Greenhouse
Gas Emissions and Sinks: 1990-1997." March 1999 (draft).
Figure 2-17: Share of NaO Emissions from Transportation. 1997
Ships and boats, <1%
Aviation, 3%
Rail,
-------
INDICATORS OF THE ENVIRONMENTAL IMPACTS OF TRANSPORTATION
Figure 2-18: Estimated U.S. Emissions of CFC-12
and HFC-134a,1990-1997
been implemented. Ozone loss in the upper atmosphere is likely to lead to an increase in cataracts
and skin cancer, could weaken the human immune system, and can have significant effects on
agriculture and plant and animal life. By signing the Montreal Protocol on Substances that
Deplete the Ozone Layer and Copenhagen
Amendments, the United States committed
to eliminating the production of all CFCs
by the end of 1995. On December 31,
1995. CFC-12 production essentially
ended in the U.S.
It is still legal to use existing stockpiles of
CFC-12, but several companies have also
developed new substitutes. In order to
make sure existing CFC-12 is not released
to the atmosphere, EPA issued regulations
under the Clean Air Act to require
mechanics to recycle CFC-12.
1991
1992
1993
1994
1995
1998
1997
Source: U.S. Department of Energy. Energy Information
Administration. Emissions of Greenhouse Gases in the United
Slates 1997. October 1998 (Table 31).
Hydrofluorocarbon HFC-134a became the
standard automobile air conditioner
refrigerant in 1994, and HFC emissions
have been growing as CFCs gradually
disappear from the automobile fleet, as shown in Figure 2-18. HFCs, which contain no chlorine,
have no effect on stratospheric ozone, but are a greenhouse gas.
2.5 HABITAT AND LAND USE

Development of transportation infrastructure has direct and indirect effects on land use and
habitat. Land is used directly for public and private transportation infrastructure, including roads,
parking lots, railway terminals, airports, and marine cargo facilities. In addition, the development
of these facilities may stimulate changes in land uses, including the development of commerci ;1,
residential, and industrial areas, which in turn can reduce or fragment habitat.
LAND USE AND HABITAT FRAGMENTATION
Use of land for transportation infrastructure can adversely impact sensitive ecological resources
such as endangered plant and^niuial species. It can also have more significant impacts through
fragmentation of habitats and secondary development. While all forms of transportation
infrastructure can adversely affect wildlife and habitat, highways and roads tend to be viewed as
the most significant cause of concern because of their pervasiveness and their linear nature, which
can form barriers to wildlife. The linear nature of highways — and railways to a lesser extent
because they tend to be narrower — divides wildlife habitat into smaller, more isolated pieces of
land that can create barriers between functional areas.

Transportation infrastructure is extensive in the United States and growing. Public roads occupied
an estimated 17,345 square miles of land in the United States in 1997, a 2 percent increase over
24
-------
SUMMARY
the amount in 1990.13 Between 1945 and 1997, public road mileage increased by about 19%.
from 3.32 million miles to 3.96 million miles. Existing rail mileage is approximately 177,000
miles of track.14 There were 18,345 airports in the U.S. in 1997, a 21 percent increase since 1980.
Although infrastructure is pervasive, national-level information on the cumulative impacts of
transportation infrastructure on wildlife and ecological systems is limited. Most transportation-
related impacts on wildlife and habitat are studied at the local level.
DREDGING AND IMPACTS TO AQUATIC RESOURCES
Dredging is undertaken to
improve navigation for water-
borne transportation. Damage
to habitat can occur because of
disturbance and removal of
bottom material and disposal of
dredged material. The U.S.
Army Corps of Engineers
dredges and disposes of about
200 to 300 million cubic yards
of material annually from
Congressionally-authorized
navigation improvement and
maintenance projects. In
addition, permit applicants
(e.g., port authorities, terminal
owners, industries, and private
individuals) dredge an
additional 100 million cubic
yards annually from navigation
Figure 2-19: Disposal/Use of Material Dredged by U.S.
Army Corps of Engineers, 1998
Mxed, More than
One Type
16.9%
Wetlands
Nourishment or
Creation
17.7%
Confined
7.2%
Beach
Nourishment and
Upland
0.5%
Beach
Nourishment
5.9%
Overboard and
Open Water
43.2%
Open Water
Upland
3.1%
Source: Army Corps of Engineers, Navigation Data Center. Dredging
Statistics Database. Information compiled as of January 1999.
projects (i.e., ports, berths, and marinas).15
Dredged material can be disposed of in open water or on land. Open water disposal can alter
bottom habitats, decrease water quality, and adversely affect marine organisms. If not
contaminated, dredged material can also be used for beneficial purposes, such as construction,
beach nourishment, land creation, wetland creation, and wetland restoration. Each year
approximately 60 million cubic yards of dredged material is disposed of in the ocean at
designated sites.16 At least 24 percent of dredged material disposed by the U.S. Army Corps of
Engineers in 1998 was used for beneficial purposes (beach nourishment, wetlands nourishment or
creation), as shown.jo Figure 2-19.
13 Estimate based on data from U.S. Department of Transportation, Federal Highway Administration.
Highway Statistics 1990, 1995, 1996, and 7997. Table HM-60.
14 Association of American Railroads, www.aar.org. as cited February 14, 1999.
15 U.S. Environmental Protection Agency. "Ocean Dumping Program Update." EPA842-F-96-003. 1996.
http://www.epa.gov/OWOW/OCPD/oceans/update3.html and Army Corps of Engineers, Navigation Data
Center. Dredging Statistics Database.
16 U.S. Environmental Protection Agency. "Ocean Dumping Program Update." EPA842-F-96-003. 1996.
http://www.epa.gov/OWOW/OCPD/oceans/update3.html
25
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INDICATORS OF THE ENVIRONMENTAL IMPACTS OF TRANSPORTATION
WETLANDS
Wetlands are a specific type of habitat that has received special attention because they perform
important ecological functions, including providing habitat for a variety of species and improving
water quality by removing nutrients and some contaminants. Highway development has
historically been a source of wetland losses, as has dredging for waterway projects.17

Of the 12 states providing information about wetland losses in 1996 305(b) reports, 6 states
reported wetland losses due to highway or bridge construction, 3 states reported losses due to
dredging, and 1 state reported
losses due to marina development, Fiaure 2-20: Sources of Recent Wetland Loss
as shown in Figure 2-20. Of
the 8 states that reported
sources of degraded wetland
integrity, 3 reported that road
construction was a cause.
Currently, most states are not
equipped to report on the
integrity of their wetlands and
national trends cannot be
drawn from this limited
information.
Residential Development / Urban Grow th

Agriculture

Hghw ay/Bridge Construction

Hydrotogic Modification

Industrial Development

Dredging

Marina Development
2 4 6 8 10
Number of states reporting
12
Although adverse impacts on Source: U.S. Environmental Protection Agency. Office of Water. National
wetlands may be unavoidable Waur Qual"y Inve"tory- 1996 Report to Congress. April 1998.
for some projects,
compensatory mitigation efforts are now undertaken to mitigate for unavoidable wetland losses.
Mitigation banking is a mitigation technique in which wetland losses are offset by efforts to
restore or create other wetlands of comparable value. For the most recent fiscal years, the ratio of
wetland creation to wetland loss from the Federal Aid Highway Program has been greater than
2.2:1. In the fiscal years 1996 to 1998, about 10,815 acres of wetlands were created in response
to 4,537 acres lost due to the Federal Aid Highway Program, for a net increase of 6,278 acres.18
There is some debate about the effectiveness of wetland mitigation options in terms of wetland
function.
WILDLIFE COLLISIONS
Collisions between vehicles and wildlife can impact certain wildlife populations. Collisions,
however, are more frequently ctegarded as a safety concern because they can lead to vehicle
damage and loss of human life. Collisions between transportation vehicles and wildlife can occur
with all modes of transportation: motor vehicles, trains, aircraft, and maritime vessels and
recreational boats.
17 U.S. Environmental Protection Agency. Appendixes from the National Water Quality Inventory: 1996
Report to Congress. http://www.epa.gov/OW/resources/9698/appendixAls
18 U.S. Department of Transportation, Federal Highway Administration. "Wetlands No-Net-Loss Summary
Data." 1998.
26
-------
SUMMARY
Figure 2-21: Number of Reported Strikes between
Wildlife and Civil Aircraft
There is incomplete data on
the extent to which animals
are killed by collisions with
transportation vehicles and
vessels nationwide. The most
complete data are for bird and
other wildlife strikes with
aircraft, which have been
monitored by the Federal
Aviation Administration since
1965. Quantitative analyses
from 1991 to 1997 show an
increasing number of
collisions over time, as shown
in Figure 2-21 Birds were
involved in 97 percent of all
strikes. As development
patterns have disrupted migratory patterns of birds, some airports have become major bird
flocking areas due to the sufficient amount of open space.
3,500
3,000
2,500
2,000
1,500
1,000
500
1991 1992 1993 1994 1995 1996 1997
Source: U.S. Department of Transportation. Federal Aviation

*''"""* " ""
Figure 2-22: Number of Animal Collisions with Motor
Vehicles reported to HSIS
Data on collisions between
animals and motor vehicles is
less complete, but also shows a
trend of increasing animal-
vehicle collisions. The Highway
Safety Information System
(HSIS) reports on motor vehicle
crashes in five states — Illinois,
Maine, Minnesota, Utah, and
Michigan — for 1985 to 1990
revealed a total of
approximately 208,300 animal
crashes over this period.
Although some crashes
involved domestic animals,
Michigan's crash report
indicated whether the crash was
deer related. For Michigan,
almost all the hit-anirnaf crashes (99.7 percent) were deer related, and recent data from Minnesota
indicate that over 90 percent of animal crashes involved deer. Data from the five states shows a
69 percent increase in animal collisions with motor vehicles over the period 1985 to 1991.
1985
1986 1987
1988 1989
1990 1991
Source: U.S. Department of Transportation, Federal Highway
Administration, Turner-Fairbank Highway Research Center. "HSIS
Summary Reports: Investigation of Crashes with Animals." March
1995 (FHWA-RD-94-156). http://tfhrc.gov/hsis/94-156.htm
INTRODUCTION OF NON-NATIVE SPECIES
Introduction of non-native species, such as non-native grasses and vegetation, can be a significant
problem with adverse consequences on habitat and ecosystems. Non-native species may compete
with native species for food" and force out existing creatures.

Ships are known to be a source of introduction of non-native species to bodies of water. Although
national data are not available on damages to ecosystems or species loss due to introduction of
27
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INDICATORS OF THE ENVIRONMENTAL IMPACTS OF TRANSPORTATION
non-native species via ship, impacts in specific bodies of water have been identified. For
example, 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.19 Highway maintenance has also been
a source of introduction of non-native species of grasses and vegetation. Highway right-of-way
has in many instances been planted with non-native grasses, which have spread and forced out
native vegetation from the area around highways.
2.6 WATER QUALITY AND AQUATIC RESOURCES