THE UTILIZATION OF LAND
USE AND TRANSPORTATION
PLANS IN AIR QUALITY
MAINTENANCE PLANNING
JUNE 1974
Prepared for
U.S. ENVIRONMENTAL PROTECTION AGENCY
RESEARCH TRIANGLE PARK,
NORTH CAROLINA
alan m. voorhees & associates, inc. ฆ transportation & urban planning
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&Pf\OQ>ฐ\
THE UTILIZATION OF LAND USE AND
TRANSPORTATION PLANS IN AIR QUALITY
MAINTENANCE PLANNING
June 1974
Prepared by
ALAN M. VOORHEES AND ASSOCIATES, INC.
Westgate Research Park
McLean, Virginia 22101
Contract No. 68-02-1388
Task Order No. 1
EPA Project Officer: John Robson
Prepared for
ENVIRONMENTAL PROTECTION AGENCY
Office of A1r and Waste Management
Office of Air Quality Planning and Standards
Research Triangle Park, North Carolina 27711
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This report was furnished to the Environmental Protection Agency
by Alan M. Voorhees & Associates, Inc. (AMV), in fulfillment of
Contract Number 68-02-1388, Task Order Number 1. The contents of this
report are reproduced herein as received from the contractor. The
opinions, findings, and conclusions are those of AMV and not necessarily
those of the Environmental Protection Agency. Mention of Company or
product names does not constitute endorsement by the Environmental
Protection Agency.
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TABLE OF CONTENTS
List of Figures v
List of Tables vii
Chapter Page
I INTRODUCTION 1
A. Requirement for Air Quality Maintenance
Plan Preparation and Analysis 1
B. Report Organization 2
II PROCEDURES FOR ANALYSIS OF AN AIR QUALITY
MAINTENANCE AREA (AQMA) 3
A. Criteria and Assumptions 4
1. Criteria 4
2. Assumptions 4
B. General Approach 5
1. Preparation of the Air Quality Analysis
of the AQMA 6
2. Pollutant Source and Control Definition . . 8
C. Summary 10
III AIR QUALITY MAINTENACE AND COMPREHENSIVE PLANNING . 13
A. General Approach for Considering Air Quality
Maintenance in the Comprehensive Planning
Process 13
1. Mobile Source Pollutants Control 14
2. Particulate and Sulfur Oxides Control ... 15
B. A Process for Analyzing the Impacts of Land Use
and Air Quality Plans or Policies 15
1. Plan Development and Evaluation 17
2. Plan Implementation 17
C. Information Access and Organization to Relate
Land Use to Emissions and Air Quality 17
D. Analytical Techniques Required to Relate Land
Use and Transportation Plans to Air Quality . . 21
IV AN AIR QUALITY CONTROL OFFICER'S GUIDE TO
URBAN PLANNING 23
A. The Comprehensive Plan 23
1. The Land Use Plan 27
iii
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Table of Contents (continued)
Chapter Page
2. The Utility of the Land Use Plan 34
3. The Influence of Land Use Planning
on Development 38
4. The Potential for Change 44
B. The 3-C Process 45
1. Current Practice 45
2. Legislative Requirements 47
3. Responsible Agencies 50
4. General Description of the 3-C Process ... 51
5. Data Sets and Formats 60
Bibliography 63
Appendices
A Projecting and Allocating Emissions and/or
Air Quality A-l
B A Review of the State-of-the-Art Quantifying the
Relationship of Land Use and Transportation to
Air Quality B-l
C Review of Selected Stuides Relating Land Use and
Transportation to Air Quality C-l
D Air Quality Models D-l
E Annotated Bilbiography of Activity Allocation
Procedures E-l
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LIST OF FIGURES
Figure Page
11-1 Preparation of the AQMA Air Quality Analysis .... 7
II-2 Pollutant Source Definition 9
III-l A Process for Relating Land Use Transportation
Plans to Air Quality 16
III-2 Information Access Requirements of a Process to
Relate Land Use and Transportation Plans to
Air Quality 18
IV-1 3-C Planning Process 46
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LIST OF TABLES
Table Page
III-l Summary of Estimates 1990 Annual Emission Rates
For Hackensack Meadow! ands Land Use Categories . . 20
vii
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CHAPTER I
INTRODUCTION
A. REQUIREMENT FOR AIR QUALITY MAINTENANCE PLAN PREPARATION
AND ANALYSIS
The 1970 Clean Air Act (as amended) has mandated all states to
identify areas which exceed the National Ambient Air Quality Standards.
These standards, as set forth by EPA, prescribe the control of sulfur
oxides (SO ), particulate matter (TSP), carbon monoxide (CO), hydro
carbons (hC), nitrogen oxides (NO ), and photochemical oxidants. This
is to be accomplished by the State Implementation Plan (SIP). In
addition, all states, pursuant to 40CFR51.12(c), are required to identify
areas that have the potential to exceed any NAAQS over the 10-year
period 1975-1985. These areas will be called Air Quality Maintenance
Areas (AQMAs), identified by the states, and reviewed by the Administrator,
who will issue an official list of designated AQMAs.
For these areas, the states will submit plans to prevent any national
standards from being exceeded over the following 10-year period. For
each pollutant in each of the AQMAs for which analysis indicates a
potential problem, tailored maintenance strategies must be submitted.
These plans, Air Quality Maintenance Plans (AQMPs), will be prepared,
adopted, and submitted in compliance with guidelines which will be
issued in August 1974 by EPA. Considerations such as terrain, mete-
orological conditions, transportation and land use planning, and economic
considerations will be incorporated into the AQMP.
The Guidelines for 10-Year Air Quality Maintenance Plans are to be
prepared in four volumes as follows:
Volume 1: Plan Preparation
Volume 2: Control Strategies
Volume 3: Land Use and Transportation Considerations
Volume 4: Case Studies
In addition, EPA will prepare a Guidelines for Analysis of Air
Quality Maintenance Areas to be released in several volumes in August
1974.
This report is a preliminary document which will provide infor-
mation to be incorporated into Volume 3 of the Guidelines for 10-Year
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Maintenance Plans and the Guidelines for Analysis. It is being released
to the states at this time to provide some insight into the possible
utilization of land use and transportation plans in the preparation and
analysis of air quality maintenance plans.
B. REPORT ORGANIZATION
The report is organized as follows: Chapter II describes a procedure
for analysis of an air quality maintenance area. This procedure utilized
land use and transportation planning data to disaggregate projected
emissions to a subcounty base suitable for dispersion modeling.
Chapter III presents a general approach for considering air quality
maintenance in the comprehensive planning process. A procedure for
analyzing the impact of land use and transportation plans or policies is
described. This analytical procedure would provide review and evaluation
of both air quality maintenance plans and comprehensive community plans.
The analytical procedure may require the development of techniques to
relate land use to air quality. These analytical requirements are
discussed.
Chapter IV presents an Air Quality Control Officer's Guide to
Planning. The comprehensive plan and the 3-C Process are described.
This discussion is intended to provide air quality planners with a brief
review of comprehensive planning and its implications for air quality
maintenance planning.
Appendix A illustrates a detailed methodology for projecting and
allocating emissions and/or air quality in Air Quality Maintenance
Areas. This methodology will be superseded by the EPA guidelines for
analysis.
Appendix B is a review of the state-of-the-art in Quantifying the
Relationship Between Land Use and Air Quality. Appendix C summarizes
selected studies which were reviewed in the preparation of the state-of-
the art summary.
Appendix D is a brief description of Air Quality Models which may
be useful in preparing an analysis of air quality maintenance require-
ments. The EPA guidelines for analysis will describe such models in
detail.
Appendix E is an annotated bibliography of activity allocation pro-
cedures which may be useful in the development of analysis procedures
for incorporating air quality maintenance into comprehensive planning.
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CHAPTER II
PROCEDURES FOR ANALYSIS OF AN AIR QUALITY
MAINTENANCE AREA (AQMA)
This chapter describes a minimum procedure for the detailed analysis
of an AQMA to determine whether a maintenance plan is necessary for any
area within an AQMA. The analysis is also intended to provide the basis
for maintenance strategy analysis and plan development.
This document'is not EPA policy at this time, as EPA is currently
preparing guidelines for analysis of air quality maintenance areas. EPA
guidelines will incorporate portions of several studies currently under
contract.
This report is being released to the states at this time to provide
initial guidance to those air pollution agencies that may be required to
participate in the preparation of an Air Quality Maintenance Plan. Some
air quality planning agencies may already have a more sophisticated
analysis procedure or technique and data base. Such agencies should
coordinate their analysis efforts with the regional EPA office to
ensure that the procedures and data base are sufficiently documented to
allow EPA to review the analysis for adequacy and accuracy.
The analysis procedure described in this document will usually not
be applicable to "natural resource" AQMA designations. Such areas must
be evaluated on an individual basis according to the available air
quality and planning information. These AQMAs should seek guidance from
their EPA regional office to coordinate analysis requirements.
Reviewers of this document are requested to submit comments directly
to EPA to facilitate the preparation of the most useful Guidelines for
Analysis document.
A review of the state-of-the-art in relating land use or activity
to air quality concluded that no model or technique is currently avail-
able that can be applied to general land use plans to determine their
air quality impact (see Appendix B).
Ideally, air quality impact analysis could be incorporated into the
comprehensive planning process (see discussion in Chapter III), to
resolve these deficiencies. However, the scope of such effort is probably
beyond the time and manpower available to complete'the Air Quality
Maintenance Plans. Therefore, the back-up methodology at this time is
one that is immediately applicable. This implies that no research
effort or model development is required, and emissions projection and
air quality analysis techniques can be performed with little additional
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expenditure of funds or manpower. These restrictions limit the accuracy
of the emissions and air quality techniques and projections described in
the following sections. The immediate results should be used as an
indication of the magnitude of the problem and a description of the
most probable spatial distribution of the problem.
A. CRITERIA AND ASSUMPTIONS
1. Criteria
In developing the methodologies for projecting and allocating
emissions and/or air quality within AQMAs, the following criteria are
established:
The techniques should be immediately available and generally
applicable in all AQMAs.
The methods should allow for pollutant-specific evaluation.
The analysis results should be useful in determining:
Areas within the AQMA that could exceed the air quality
standards for any given pollutant by 1985.
Maximum pollutant concentration in those areas that would
occur without a maintenance plan.
Significance of the major source types to the air quality
problem, i.e., manufacturing sources, power plants,
mobile sources, or area sources.
2. Assumptions
Regional air pollution source growth is a by-product of the socio-
economic and transportation development. This development process is
not static, and the planning process this is intended to monitor and
rearrange this development is a continuing process. Guidelines for AQMA
an Development state that the plan and assumptions should be reviewed
a er five years and at five year intervals thereafter. In the interim,
m?n+hฐrin^ an(* survei^ance will report the progress and effectiveness
ฐh-J"aintฎnance measures. However, if any of the planning data upon
w "ich the maintenance plan are based change significantly between reviews,
the impact of such change on the maintenance effort should be investi-
gated immediately.
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The assumptions inherent in the application of the methodologies to
analysis of an AQMA are as follows:
Air quality maintenance planning assumes that the air quality
standards will be achieved by existing implementation control
measures. State Implementation Plans (SIP) adequately account
for growth between the time of plan implementation and the
date for achieving the primary standards (1975,1977).
Some form of land use plan or demographic data are available
for each county in the AQMA.
If the AQMA is designated for Carbon Monoxide, some form of
detailed traffic network data are available and the impact of
the Transportation Control Plan on the traffic network and
associated 3-C Transportation Plan has been accounted for.
Before applying the projection or disaggregation techniques
specified in this document, the state has upgraded the county
emissions inventory using the techniques specified in the
Manual of Instructions for Projecting County Emissions (prepared
by Booz-Allen under contract to EPA).
B. GENERAL APPROACH
The purpose of the detailed analysis of projected air quality in
the AQMA is to support air quality maintenance plan (AQMP) development
by providing:
A description of where and when a subarea within the AQMA may
be expected to exceed the air quality standards without an
AQMP, and
An estimate of the effectiveness of proposed AQMP control
measures in reducing existing emissions or guiding the location
of significant new sources of emissions.
To serve this purpose a detailed analysis of the AQMA should provide
the following two products:
An air quality analysis of the AQMA indicating the spatial and
temporal distribution of the pollutant emissions or concen-
trations in sufficient detail to relate to proposed strategies.
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A complete definition of the pollutant and related source
problem that will serve as an aid to strategy development and
analysis. The preparation of these two products is described
in the following sections.
1. Preparation of the Air Quality Analysis of the AQMA
The purpose of the detailed air quality analysis is to determine
where within the AQMA air quality standards are expected to be exceeded
within the 10-year plan period, and the extent of the problem in each
area where an air quality standard is expected to be exceeded. Fig-
ure 11-1 illustrates the general steps required to prepare the air
quality analysis of an AQMA.
Step IPrepare a Controlled Emissions Inventory
For each pollutant of concern, a projected inventory of emissions
should be prepared for the expected year of attainment of air
quality standards for that pollutant (1975 or 1977). This inven-
tory should reflect the impact of all existing SIP controls so that
any further control requirements can be analyzed.
Step IIPro.iect 1980, and 1985 Emissions and Air Quality for
the AQMA
For each pollutant of concern, prepare a projection of the
1980 and 1985 emissions and resultant air quality distribution.
Details of a methodology for projecting and allocating emissions
and air quality for each pollutant are described in Appendix A.
Step IIIDefine Areas that will Exceed the Ambient Air Quality
Standards Mi thin the AQMA for 1980 or 1985
Compare the emissions or air quality projection obtained from
Step II with the primary and secondary air quality standards.
Where short term averages are specified in the NAAQS, techniques
should be used to relate the annual projections to short term
conditions. These techniques will be described by EPA in the
Guidelines for analysis of AQMAs.
Ideally, a calibrated diffusion model would be applied to a detailed
projected emissions inventory to obtain the desired spatial and temporal
definition of the pollutant problem. If such a model has been calibrated
for the AQMA, it should be applied to a data base that is sufficiently
detailed and accurate to support the model. If 1980 or 1985 air quality
is to be modeled, the projected emissions data must also be of sufficient
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FIGURE II-1
PREPARATION OF THE AQMA AIR QUALITY ANALYSIS
STEP I
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detail and accuracy to justify application of a calibrated diffusion
model. Where either the calibrated diffusion model is not available, or
the data base required by the model can not be prepared within the time
frame for AQMA analysis and AQMP development, the following procedure is
recommended:
ง Prepare a study plan to develop the required data base.
t Obtain guidance from the EPA regional office on the applicability
of various diffusion models to the AQMA.
2. Pollutant Source and Control Definition
Figure I1-2 illustrates the methodology for preparing a definition
of the pollutant and source problem. This problem definition is to be
performed for each area within the AQMA that the analysis indicates a
maintenance plan will be required. Such an area may range from an
entire county to just a few square kilometers. Following is a discussion
of the steps presented in Figure I1-2.
Step IOrganize the Emissions Inventory
Prepare a table of emissions by source group for each pollutant
of concern, ranking the sources by order of contribution to total
AQMA emissions. The analysis of air quality should supply this
information. The sources should be grouped by the following source
types:
Area Sources
Power Plants
Point Sources
Mobile Sources
This inventory can be further refined by ranking within source
categories if data are available.
Step IIEstimate the Relative Source Growth and Control Factors
Prepare a table, by source type, of projection factors, growth
estimates, and control factors using best available projection
data, economic factors, and area control regulations.
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FIGURE n-2
POLLUTANT SOURCE DEFINITION
STEP I
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Step IIICatalog the Regional (AQMA) Pollutant Source Problem
for 1975, 1980, 1985
The data developed in Steps I and II can be catalogued to
provide a description of the relative source and pollutant problem
in the AQMA. This table will provide an indication of the following:
The significance of each source type to the pollutant
problem as it exists (1975), in the near future (1980)
and long-term (1985)
The existing level of source control
The possible control of a source type by either direct
source control measures or source location guidance
C. SUMMARY
The methodologies described above represent an approach considered
to be applicable in most urban areas within the period for plan analysis
and development. It may be expected that each area will make modifica-
tions to the methods described, based on local conditions and resources.
There are several areas of deficiency in this approach that may
require considerable effort to resolve. The most significant deficiencies
are:
The accuracy, completeness, and level of detail of the existing
emissions inventory is inadequate to support the level of
analysis required to define the air quality problem and the
source contribution to that problem. Time and effort must
first be devoted to upgrading the existing inventories.
The analysis approach is a one time, sequential approach
resulting in a description of projected air quality. Emissions
control plans, energy reduction plans, and transportation
plans are currently being developed or revised that will have
a significant impact on the basic assumptions of the growth
and distribution of all pollution sources. Therefore, the
growth rates and distribution factors used in the emissions
projection techniques may be in considerable error. To be
effective, the analysis approach must be responsive to these
plans and other community policy decisions that may impact the
growth rate or distribution of sources. The preferred analysis
approach would be an iterative, continuing process, capable
of simulating response to policy changes by changing the
projection assumptions.
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The basic emissions inventory, projection data, and dis-
aggregation or distribution data are not in comparable formats.
In addition, where sets of each of these data types are obtained
from more than one jurisdiction or agency responsible for
collecting such data, the format may vary. A detailed, standardized,
regional data base and data handling system are needed.
The techniques for relating emissions to air quality vary
considerably in the level of detail and format of input data
required. If air quality is the intended end product of the
analysis process, the development of the emissions data base
and projection data must be coordinated with the requirements
of the diffusion model(s) to be used. This coordination does
not currently exist.
The following chapter describes an analytical process for relating
land use and transportation to air quality that could be incorporated
into the comprehensive planning process. This would provide a con-
tinuous mechanism for resolving the deficiencies in the available analysis
approach. The discussion is conceptual in nature and is not intended to
be definitive. A definitive process for a community should include an
evaluation of available institutional resources and a formulation of the
procedure for incorporating air quality maintenance considerations into
comprehensive community planning. Air Quality Impact Analysis would be
only one tool in the formulation of a Community Planning Policy.
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CHAPTER III
AIR QUALITY MAINTENANCE AND COMPREHENSIVE PLANNING
A. GENERAL APPROACH FOR CONSIDERING AIR QUALITY MAINTENANCE
IN THE COMPREHENSIVE PLANNING PROCESS
Ambient air quality is a function of the distribution of pollutant
sources as well as the physical, meteorological, and climatological
characteristics that determine how pollutants will concentrate within a
given area. The distribution of the sources of emissions is determined
by land use and its attendant activities. The maintenance of air quality
depends upon the long-term changes in these land use activities. Air
quality considerations must therefore be made a part of the comprehensive
planning process.
A regional comprehensive plan is a necessity if long-range land
use and environmental objectives are to be attained. While air quality
considerations may be incorporated into local planning efforts, it is
obvious that the overall guidance must be provided from a regional
perspective. The technical and administrative problems of local planning
to achieve air quality, support the need for a regional approach to
develop policies related to air resource management. For example:
Local efforts to improve air quality cannot be accomplished
without comparable efforts at the regional level.
Local land use plan impacts cannot be quantified without a
regional approach.
Local land use plan impacts on traffic volumes cannot be
evaluated except within the context of regional multimodal
traffic models.
ง Oxidant is an areawide pollution problem which cannot be
solved on a local basis.
Therefore, in future regional comprehensive plans, air quality
maintenance considerations will constitute a critical segment of the
policies relating to urban form, open space planning, stationary source
location, and transportation planning. Implicit 1n this 1s the notion
that the regional plan can be an effective Instrument for attaining long-
range air quality and other environmental objectives only if it goes
beyond simply compiling local land use plans Into a regional format.
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Goals and policies as they relate to air quality must be clearly artic-
ulated in order to provide local planning agencies with the constraints
that should be placed upon land use decisionmaking.
In order to accomplish the institutionalization of the air quality
maintenance segment into the comprehensive plan, three areas must be
explored:
Planning
Implementation
Enforcement
Planning incorporates air quality considerations into the comprehensive
plan and develops a maintenance strategy for each type of pollutant.
Implementation and enforcement deals with achieving compliance with air
quality standards upon which the maintenance plan and strategies are
based.
These aspects of the institutionalization of air quality maintenance
planning are discussed as two elements(1) mobile source planning and
implementation, and (2) planning and implementation for control of
particulates and S02. This distinction is made as these elements parallel
transporatation planning and land use planning respectively.
1. Mobile Sorce Pollutants Control
Planning - The 3-C agency should incorporate air quality
maintenance constraints into the evaluation of alternative
transportation plans for the five-year updating. This could
be accomplished by an annual review of the impact of the 3-C
plan on air quality. Analytical techniques, such as the
SAPOLLUT* model are currently available for such use.
t Implementation and Enforcement - The A-95 review process is
the one mechanism for implementation of the mobile source
planning policies. The process would be reinforced by the
"consistency" review and determination, indirect source review,
and the Transportation Control Plan. Enforcement responsi-
bility should remain with the state air pollution control
agency, and where appropriate, with the regional EPA. Many
legal, technical, and administrative issues must be resolved
to implement such a program. The preparation of the AQMP
should address these issues and propose a timetable for im-
plementing.
~Final Manual: Special Area Analysis, U.S. Department of Transportation,
August 1973.
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2. Particulate and Sulfur Oxides Control
Planning - As the region develops alternative land use plans,
the constraints of air quality standards must be an element of
environmental impact. The impact of proposed public and
private development upon the land use plan must be determined.
Proposed projects that involve Federal funds are required to
submit Environmental Impact Statements. The planning agency
role is to review projects for land use compatibility as well
as air quality and other environmental impacts.
9 Implementation and Enforcement - While the control of projects
that have Federal funding is adequately covered by the require-
ments for an Environmental Impact Statement, the long-term
regional impact of all projects must be considered. As compre-
hensive plans are developed with air quality constraints, the
environmental impact review process should include compatibility
with the plan as a criterion for evaluation.
Enforcement of air quality control for proposed sources which
do not have Federal funding should be the concern of a permit
system for State air pollution control agencies. In order to
incorporate considerations of the effects of such sources on
regional growth and the resultant air quality, the compre-
hensive planning agency should be notified of each request for
a permit to construct. The results of the planning agency
review should become a criterion for permit approval.
B. A PROCESS FOR ANALYZING THE IMPACTS OF LAND USE AND AIR QUALITY
PLANS OR POLICIES
In order to consider air quality in the plan development process,
some analytical process must be available to define the impact of alter-
native land use and transportation plans or policy changes on air
quality. In addition, the preparation of air quality maintenance plans
requires the analysis of the impact of air quality control strategies on
land use and transportation and the resultant impact on air quality.
A conceptual analysis process for relating land use and/or trans-
portation plans to air quality is shown in Figure III-l. Since the
process is iterative, it can also be used to evaluate the impact of area
land use and transportation plans. This process could be applied at
several points in the development, evaluation, and implementation of air
quality maintenance plans as follows:
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FIGURE III-L
A PROCESS FOR RELATING LAND USE AND
TRANSPORTATION PLANS TO AIR QUALITY
Suggest
Modifications
Area Plans
Land
Use
Transportation
Control Technology
and Plans
-Mobile - TCP
-Stationary - SIP
- Indirect - AQMP
Emissions
Model
Dispersion
Model
Estimate of Emissions:
-Stationary
-Mobile
Estimate
of
Air Quality
Meteorology
Topography
Background
Air Quality
Standards
Evaluation
Other
E valuation
Criteria
(NAAQS)
Model
Determ ine
Nature of
Problem
No
Yes
-~ No
Problem
ILLUSTRATIVE PROBLEMS:
-Source Control
"Intensity and Type
of Land Use
- Location
-Transportation
- Parking
-Pricing
"Timing of Development
ILLUSTRATIVE EVALUATION
CRITERIA*.
- Energy Needs
- Environmental Impact
- Physical Constraints
- Socioeconomic Impact
- Air Quality Maintenance
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1. Plan Development and Evaluation
t Evaluation of the air quality or emissions impact of existing
land use and transportation plans.
Evaluation of the air quality or emissions impact of alternative
future land use and transportation plans under different
assumptions of control technology or energy needs.
Evaluation of the impact of AQMP strategies, Transportation
Control Plan Strategies (TCP), and other SIP strategies on
land use and transportation requirements and the resultant air
quality impact.
2. Plan Implementation
Suggest modifications to transportation plans, land use plans,
or SIP's at plan update or critical review.
Suggest an emissions allocation procedure based upon the
estimate of emissions.
The process flow diagram (Figure III-l) implies that land use and
transportation plans or policies must provide information relevant to
emissions that would result from the plan or policy before it can be
translated into the impact in air quality. The following section
briefly describes the information required to relate land use to air
quality and discusses the availability of techniques to provide this
information.
C. INFORMATION ACCESS AND ORGANIZATION TO RELATE LAND USE TO EMISSIONS
AND AIR QUALITY
A generalized flow of information required to relate land use to
air quality is given in Figure II1-2. As can be seen, the land use or
transportation plans do not currently provide the emissions data needed
to estimate air quality impact as required by the process shown in
Figure III-l. If air quality considerations were a determining factor
in the land use planning process, basic emissions data would be collected
in conjunction with the basic inventory requirements of a land use or
transportation plan.
The content and form of current emissions inventories is mainly a
function of modeling requirements. Therefore, one or more intermediate
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FIGURE III-2
INFORMATION ACCESS REQUIREMENTS OF A PROCESS TO
RELATE LAND USE AND TRANSPORTATION PLANS TO AIR QUALITY
STEP
Models or Techniques
Information Generated
Land Use Plans and
Transportation Plans
(Activity Allocation,
Surveys, Economic
Studies, etc.)
Land Use ActivitW
T r asportation
N etwork
Conversion Factors
Activity Parameters:
Fuel Use/
Demand Data,
Process Rates, etc.
Emission Models
Emission Factors
Existing Inventories
Emissions Inventory
Area-Wide Emissions
by Pollutants by
Time Period
4
Emissions Allocation
or
Disaggregation Model
Emissions on a
Sub-Area Basis
as Required by
Air Quality Model(s)
5
Air Quality Model
Air Quality
Regional and Sub-Area
Evaluation Model
or Criteria
Air Quality Impact
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modeling or conversion techniques is needed to translate the land use
activity data into the required emissions inventories.
Steps 1 and 2 of the flow diagram indicate that the land use and
transportation plan must first be quantified to provide data relevant to
the "intensity" of use in the specified land use category. This has
been done historically by a combination of economic analyses, surveys
(origin-destination studies), and application of activity allocation
models. Land use activity allocation models have been developed within
a wide range of complexity and data base requirements. A brief anno-
tated bibliography of activity allocation models is given in Appendix E
to this report. Where such models have been executed, the results would
be useful in providing the input necessary for the development of the
emissions inventory activity parameters (Step 3). However, their results
are specific to the communtiy evaluated and the basis for conclusions
should be carefully considered before attempting to relate them to other
areas.
In the Hackensack Meadowlands Air Pollution Study (see Appendix C),
estimated emission rates for various land use categories in the areas
were developed (see Table III-l). These emission rates are very limited
in accuracy because of the limited and generalized land use and activity
data upon which they are based. However, they may be useful to planners
as a rapid evaluation technique for gross planning estimates at the early
stages of plan design. It is recognized that the emission rates in this
table are highly specific to the Hackensack planning district, and it
would be necessary to create such a table specific to each area of
concern. An attempt was made in the "Air Pollution/Land Use Planning
Project" (see Appendix C) to prepare such a table which would be gen-
erally applicable; however, the results indicate that these factors
cannot be generalized. By generation of Table III-l, or by similar
techniques, the emissions inventory for the plan area can be developed
for each specific pollutant.
At this point, a rough estimation of the total regional (plan area)
air quality impact of the given plan could be made by using a simple
proportional model such as "roll-back" to relate emissions to air quality.
However, this procedure gives no indication of the resultant spatial
distribution of the pollutants within the region (plan area). An air
quality planner using a regionwide roll-back technique to evaluate air
quality impact of a proposed land use plan could conceivably allocate
the pollutant sources in such a manner as to violate the air quality
standards within a subarea, although the regional air quality level
would still appear to be within the air quality standards. In order to
locate and avoid such "hot-spot" problems in the plan, the emissions
19
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TABLE III-l
SUMMARY OF ESTIMATED 1990 ANNUAL EMISSION RATES
FOR HACkENSACK MEADOIVLANDS LAND USE CATEGORIES
Pollutant Emissions
Land Use Category
(lb/year/acre)
i
TSP
SO.,
CO
i ..
Hl
NO
X
Residential
ฆ
10 Dwelling units/acre
:s
1
55
12
7
2 Q " tl I'
' ISO
120
4
54
85
30 " " "
IfcW
120
4
54
85
50 " "
:so
160
5
75
120
80 " " "
200
140
4
63
100
Commercial & Industrial
Commercial
60
45
1
12
95
Manufacturing
Light
1100
1100
10
140
850
Heavy
5400
5400
bO
900
5400
Research
2
15
1
5
35
Distribution
60
45
1
12
95
Special ,l)se
60
45
1
12
95
Airport
100
1000
3000
350
100
Transport Center
180
150
2
36
300
Cultural Center
45
35
1
9
70
Open Space
0
0
0
0
0
Other^
Emission Factors
Highway (lb/106 VMT^
700
400
11000
1000
1500
Parking Lots (lb/10 hrs idling)
4
4
12
3
1
(1) Assumes 400,000 flights/ye,ir from Tetcrboro Airport, and 700 acre area.
(2) Activities are not specified on basis of emissions/unit area.
Source: The Hackensack Meadowlands Air Pollution Study, Summary Report,
Environmental Research and Technology, October 1973.
20
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data must be disaggregated to the level of detail required to visualize
such problem areas.
If an air quality model (Step 5) is being used to evaluate the
effectiveness of a land use control strategy, the data allocation pro-
cedure and air quality model used must also be representative of the
level of detail required by the strategy definition. For example, a
land use strategy that requires control of the location of specific
sources would require a site-specific emissions data allocation system.
Many air quality models are currently in use in specific areas or
studies. These models range from the proportional models such as "roll-
back" to highly complex models that are related to fundamental theory.
The utility of these air quality models is dependent on the specific
application. A limited review of some types of air quality models and
their applicability is given in Appendix D to this report. An addi-
tional guideline document is being prepared by EPA to discuss air quality
models for air quality maintenance plans. As the model complexity or
level of analysis requirements increase, the concurrent emissions in-
ventory requirements (Step 3) increase. Ideally, quantified land use
should provide the emission inventory to meet the scale requirements of
the air quality model. If such detailed quantified land use and activity
data are prepared, Step 4 would become unnecessary.
D. ANALYTICAL TECHNIQUES REQUIRED TO RELATE LAND USE AND TRANS-
PORTATION PLANS TO AIR QUALITY
It is apparent from the previous discussion that a community-
specific analytical process must be developed to relate land use or
transportation plans to air quality. The process would consist of all
the analytical techniques or models required to provide the information
needed to relate comprehensive planning decisions to their impact on air
quality, and air quality planning decisions to their impact on land use
and activity. The process should also provide information and guidance
for the planner, local legislative bodies, and the public so that they
might clearly perceive the air quality impact of their planning decisions.
The process developed to relate land use to air quality must operate
at two levels:
First, it must be able to relate the impact of the local
planning decision on the subarea land use activity, and
resultant air quality.
Second, it must be able to relate this subarea or project
level decision to its impact on the total regionwide (AQMA)
air quality.
21
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In addition, the process developed should have the following charac-
teristics:
It must be specific to the AQMA or planning area in order to
fully utilize the information resulting from the 3-C or land
use plan.
It must relate to other planning effortsenvironmental,
socioeconomic, etc.
It should provide useful and reliable information to assist
the formulation of policy and administrative guidelines.
It should provide relevant information on subarea (i.e.,
county or planning district) issues that can be communicated
simply to planning officials and the community.
It should address pollutants of concern.
It should incorporate unique terrain, and meteorological
features, that may affect ambient air quality.
It should be flexible and be able to incorporate the state-of-
the-art in economic projections, land use models, emissions
models, air quality models, techniques for quantifying impact,
new source control technology, etc.
It should provide information in a form that can be simply
communicated to officials, citizen groups, and other units.
Development of techniques or models that require basic research,
extensive data base development, or are costly should be deferred beyond
the one-year time period given for AQMA plan development. Development
of a sound data base and detailed quantification of regional land use
and transportation plans should be considered as an integral part of
this process development.
22
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CHAPTER IV
AN AIR QUALITY CONTROL OFFICER'S GUIDE TO URBAN PLANNING
Serious efforts to include air pollution considerations in planning
activities as well as to include land use policies or controls in pro-
grams for achieving air quality standards is a recent phenomenon. Impetus
has been given to the introduction of land use and transportation con-
sideration into air resource management by Federal legislation requiring
states to identify areas which, due to existing air pollution levels
and/or projected growth rates, may have the potential for exceeding
federally established air quality standards.
These areas are designated as Air Quality Maintenance Areas (AQMA).
The states must then perform a thorough air quality analysis of each of
these AQMAs and develop a plan demonstrating how National Air Quality
Standards will be maintained if such analysis indicates that the stan-
dards would otherwise be exceeded.
Because it is anticipated that the agency preparing the air quality
maintenance plan in many areas will be the air pollution control agency
this chapter is directed toward personnel in such agencies. Therefore,
it contains a generalized description of land use and transportation
planning including the types of information in the plans, the legal
aspects of the plans, and a discussion of the responsible agencies.
A. THE COMPREHENSIVE PLAN
The land use plan, as a document, exists within the broader framework
of the comprehensive plan (sometimes called the master plan). "It (the
comprehensive plan) indicates in a general way how the citizenry of a
jurisdiction, represented by its leaders, wants its community to develop
physically over the next 20 to 30 years."** In this context, the word
"comprehensive" generally means that the developed plan encompasses all
geographic parts of the community and all functional elements that bear
on physical development. In the past, the emphasis on physical develop-
ment has often excluded considerations of the environment, resulting in
the generation of negative impacts. A redefinition of the comprehensive
planning process that seeks a more balanced approach to the considera-
tion of economic, social, and environmental variabiles is a recent factor
in the planning process. At the present time, several agencies, including
EPA and the Department of Housing and Urban Development (HUD), are
* Clean Air Act (as Amended in 1970)
**A1an Black, "The Comprehensive Plan," Principles and Practice of Urban
Planning, edited by William I. Goodman and Eric C. Freund (Washington,
D.C.: ICMA, 1968).
23
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developing a procedure to reflect this expanded concept. This new
approach, however, is presently found in very few plans, since most have
predated it.
The comprehensive plan as a policy statement presents a picture of
proposed development of both public and private land within the planning
area. The comprehensive plan as a schematic map presents the spatial
allocations and location of various land use categories plus transporta-
tion and community facilities. Although there is no rigid format for
the plan, the elements included have tended to become standardized. The
following is a generalized sequence of the information included:
Background Information - This includes a statement of the
community goals reflected in the plan, basic assumptions, and
descriptions of the population, economy, and existing land
use. Many plans also include such geographic considerations as
soils, geologic factors, flood plains, and topographic con-
ditions. In order to provide the reader with the proper
perspective, the area's history and regional setting are also
included.
Functional Plans - This series of specific land use and facilities
plans form the body of the document. The plans generally
include transportation, residential areas, and recreation and
community facilities. Depending on the area, the plans may
also include proposals for public utilities, commerce, and
industry.
The Comprehensive Plan - The final product is generally a map
of the planning area on which the major functional plans are
brought together to show their interrelationships. The map
may be supplemented with an implementation strategy.
In spite of the fact that the elements included in a plan are
fairly standard, there is a wide variation in the level of detail. This
variation is in large part due to the strong motivation by the Federal
government for the development of comprehensive plans at various juris-
dictional levels, from local to regional and state.
Although comprehensive planning has existed as a concept for over
50 years, it only began to move to the forefront of local planning
agency concerns after World War II. The impetus was caused by the
Federal government's increasing tendency to make financial assistance
conditional upon conformance to a local comprehensive plan. This require-
ment has been supplemented by Federal funds to be used for the purpose
of preparing these plans. Two of the chief sources of this type of
Federal planning grant have been Section 701 of the Housing Act of
24
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1954, as amended, (the "701 Program") and the transportation planning
grants under the Federal-Aid Highway Act of 1962 (the 3-C Process). The
701 planning grants were made under these programs to established state
or local planning units which apply for them. Under these grants,
the primary concern was with housing, transportation, or general land
use. However, whatever the primary focus, planning was generally inte-
grated to some extent into the total urban scene. In spite of these
programs, not every area has a comprehensive plan, or the more basic
land use plan.
A basic component of the Comprehensive Plan is a document, or
series of documents, known collectively as the land use plan. This plan
is primarily concerned with the geographic allocation and amount of land
development required for the various space-using functions of urban and
suburban 1ife--industry, wholesale business, housing, recreation, educa-
tion, and the religious and cultural activities of the people. Therefore,
the land use plan has a great influence on the other functional areas_
included in the comprehensive plan such as transportation, public facil-
ities and public utilities. For this reason, this part of the compre-
hensive plan provides a direct link between planning and environmental
quali ty.
The land use plan differs from the comprehensive plan in that it
generally deals only with the uses of private land, although there are
planning agencies that do not make this distinction. The land use plan
should not be confused with the zoning map or the zoning ordinance. The
land use plan is not legally binding; hence, it is essential that the
necessary legislation be prepared, adopted, and enforced to transform
the general concepts into patterns which have legal substance.
Zoning is one of several legal devices for implementing the proposals
for land development set forth in the plan. The zoning map is a part of
the zoning ordinance and is generally conceived as a scheme of districting
an area for purposes such as regulating land use, population density,
lot coverage, bulk of structures, and parking requirements. Both the
zoning ordinance and the zoning map may be more detailed than the land
use plan.
The process for developing a land use plan is not fixed; therefore,
the procedure described in this section is generalized. The format and
procedures presented here have been adapted from the work of F.Stuart
Chapin. For a more detailed discussion of these topics, the reader is
referred to his book, Urban Land Use Planning.* It should be stressed
that the analytical procedures presented in this section do not repre-
sent a definitive listing; rather, they represent the approaches most
commonly used by planning agencies at different levels.
~
F. Stuart Chapin, Urban Land Use Planning (Urbana, Illinois: University
of Illinois Press, 1965).
25
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The traditional approach to land use planning begins with a pro-
jection of future economic growth in the area. This projection is based
on trends in both the national and the regional economy. Given the pro-
jection, in terms of the amount and type of economic activity translated
into employment levels, future population is estimated. Projections of
economic activity and population are then translated in turn into esti-
mates for future land demand for industrial, commerical, residential,
and public activities. This represents the demand side of the process,
which must be matched against the supply of land. Land supply is eval-
uated according to availability (vacant or unused land) as well as to
the available land's suitability and capacity for the various proposed
activities. Availability is determined through an inventory of existing
land use. The suitability and capacity of a parcel is defined in terms
of accessibility, size, and general physical quality. Quality denotes
environmental characteristics to a varying degree. "Generally, consid-
eration is given to a parcel's buildability considering soil and slope
conditions. The basic assumption of this approach is that economic
growth will bring positive benefits to the community and that such
growth can best be fostered by designing the land use pattern to maxi-
mize accessibility within the system of economic activity."* This
approach to land use from a purely economic point of view has been
coming under increasing scrutiny because of increasing sensitivity to
environmental effects. Future land use planning procedures will evaluate
the suitability of land for certain uses from the point of view of cost
to the developer, from the perspective of land as a resource to be
protected from misuse, and from potential environmental impacts of its
development.
This process results in a document that is the basic element of the
comprehensive plan. It is generally presented toward the end of the
report as a composite of those functional plans for specialized types
of land use. The generalized land use plan for the area usually does
not show individual detailed parcel uses. The land use areas are broad,
and the boundaries are sometimes imprecise. For the exact location of
facilities or parcel uses proposed, sector or neighborhood development
plans should be reviewed.
In a very few large urban areas, e.g. Baltimore, Dallas-Ft.. Worth,
and San Diego the land use and land activity patterns have been quanti-
fied for a computerized land use/land activity model. This procedure
permits evaluation and projection of land activity over time; however,
it is not readily available at present in most urban areas, and thus
are not discussed in this chapter. Detailed discussion of the land use
models may be found in Appendix E and the application to such models
may be found in Appendixes B and C.
*
Edward J. Kaiser, et al., "Land Use Planning: The Cornerstone of Local
Environmental Planning and Control," Land Use and the Environment, edited
by Virginia Curtis (Washington, D.C.: EPA, 1972).
26
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The following sections will discuss the land use plan in greater
detail to provide the evaluator with the necessary information to use
the plan in the determination of the air quality for an area. Particu-
lar attention will be given to the preliminary studies that form the
basis for the plan as well as the data that they provide, which may have
applicability for air quality analysis.
1. The Land Use Plan
The land use plan, as a pattern for existing and proposed activities,
provides a map of potential patterns of air pollution. For the purposes
of air quality modeling, one way of looking at sources of pollution is
to place them in one of the following categories:
Point Source - a single major emitter located at a point. A
similar type of source is that designated as "stationary."
Line Source - a major highway link or other transportation
link denoted by its end points. This source is also occa-
sionally referred to as a "mobile" source to differentiate it
from "stationary" above.
Area Source - An aggregation of smaller, less specific sources
that exist over the space of an area. This includes residen-
tial emitters and single emitters and highway links deemed too
small to be considered as Individual point or line sources by
the model. The boundaries of the area are not fixed. They
may or may not coincide with those of political jurisdictions.
The total area may be divided up into squares and referenced
to some type of grid coordinate system if this is the form the
model requires.
As the land use plans (as differentiated from comprehensive plans)
generally deal with the allocation of private land, public facilities
and major transportation facilities may not be detailed. This, of
course, means that major line sources or point sources that are sited on
public land may not be shown on the map. In order to consider major
transportation sources of pollution, the transportation element of the
comprehensive plan or the 3-C transportation process will have to be
used as a base. Public land uses (point and area sources) will usually
be shown on the comprehensive or public facilities plan and hence those
will provide a basis for part of the air quality analysis.
Given the categories that are included in the plan, this section
will discuss how the Information used 1n the calculated demand for a
particular use can be used 1n the projection of air pollution emissions.
In addition, the supplementary Information presented 1n each functional
plan will be evaluated for Its utility in air quality projections.
27
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a. Preliminary Information and Studies - In general, the minimum
information produced through the studies done prior to the development
of the land use plan usually include:
t Current and forcasted urban populationthe total and by sex
and age groups
Current and forecasted urban area employment by major SIC
(Standard Industrial Classification) category
Map and tabular summary of existing land use area by planning
district (if that is the system used) and category
Map and tabular summary of vacant and renewal land charac-
teristics and area
t Summary of the current stock of dwelling units by structure
type and planning district*
The specific types of studies that are often done to determine the
allocation of land include economic, employment, population, activity,
and urban land. These studies will be examined briefly, with each
discussion describing the types of methodologies that can be used to
obtain the relevant statistic. This will then be evaluated for its
utility in projecting air quality.
Urban Economy - "The destiny of an urban center is controlled by
the extent and character of its productive or income-producing activities
and their general vitality. Studies of the economic basis of these
activities hold the key to how the city has developed, where it is
today, and what its future prospects are."** Viewed in this way, the
economy conditions the amount of development that occurs, and, hence,
influences land use projections. With a knowledge of the trends in the
economy, the planner is better able to develop yardsticks which can be
used in estimating land requirements. "As an example, studies of employ-
ment are a key element in population forecasts, and population estimates
are, in turn, used for scaling land development needs. Estimates of
future land requirements for industrial uses are based on manufacturing
employment trends, and future space needs for commercial uses draw upon
employment trends in wholesale trade, etc. Finally, plans for various
sizes of shopping centers draw upon studies of population and purchasing
power in and around the urban center."***
* Chapin, Op. Cit.
** Ibid.
***Ibid.
28
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Two standard approaches to economic projections are the (1) region-
ally oriented and (2) the urban centered. Whichever approach is taken,
the results are a set of statistics showing the projected growth for
various types of industry in the area. These are then used as a base
for other types of projections.
t Regional Orientation - The underlying assumption of this
approach is that economic activity in the urban center is
affected by other centers of economic activity in its imme-
diate region and is ultimately linked to the national economy
as a whole. Hence a city's future economic position is
dependent on its capacity to develop new productive resources
and to expand existing ones in relation to other cities in the
region engaging in the same activities.
Urban Centered - The assumption here is that the analysis
begins in the urban area but at the same time is extremely
focused in that it seeks to explain the city's economic struc-
ture in terms of the goods and services that it produces that
are consumed outside of the localized area of study. It
identifies it as the "base of the urban economy the goods and
services that are consumed externally."
Presented below are three approaches to the study of regional
spheres of influence:
Input-Output Analysis - An approach concerned with the dynamics
or corrmodity flows between aggregates of industry. These
aggregates (focal points) can be single urban centers or a
whole metropolitan complex of centers.
9 Regional Amounts System - This is designed to analyze all
forms of income-producing activity.
, Approximation Analysis - Uses conventional divisions of the
nation into regions, subregions, etc., and by crude step-down
procedures from the larger parent area, develops gross mea-
sures of how the parts of the whole are estimated to share in
total national productive activity.
The primary urban-centered approach to the calculation of economic
growth is the economic base, which has received rather extensive appli-
cations in city planning analyses. Base theory considers the structure
of the urban economy as made up of two broad classes of economic efforts~
29
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(1) the basic activities which produce and distribute goods and services
for export to firms and individuals outside a defined localized economic
area, and (2) the service or nonbasic activities whose goods and services
are consumed at home. The concept holds that basic lines usually means
growth in service activities and thus growth in the total economy.
The preferred method of determining what proportion of current
employment is engaged in activities which produce for export and what
proportion is engaged in activities producing for local consumption is
through a local economic base survey.
Employment Studies - Employment forecasts serve two functions in
the land use planning process: (1) they provide information of concern
to population studies which, in turn, are used in estimating space needs
for residential areas, shopping centers, and community facilities; and
(2) they supply a direct yardstick for use in determining the land
requirements for industrial and non-retail commercial areas.
In industrial areas, space requirements are estimated on the basis
of adopted industrial density standards, i.e., manufacturing workers per
acre of industrially used land or standards of a more detailed nature
based on floor area, shift size and structural density. In wholesale
areas, space requirements are derived from various floor area standards
of employees per square foot of building space. Office space require-
ments are developed on the basis of floor area standards relating
employment to space taken up by the category of use.
Various sources of employment statistics are available for use in
estimating future employment:
Th_e U'S. Bureau of the Census - From the decennial reports are
statistics such as total labor force, the civilian labor
force, total employment, manufacturing employment.
Census of Manufacturers
Census of Business
There are various methods of forecasting employment; several
commonly used methodologies are:
Input-Output Analysis. - Using the estimates of the effective
demand for all the various economic lines in the area of
concern for a particular year and estimates of labor produc-
tivity for all industries and for the subcategories of manu-
facturing, finance, insurance, and real estate as givens, the
actual employment estimates are obtained by dividing values of
30
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estimated future output by the appropriate values for output
per worker. The method, however, presents a great many problems,
particularly with regard to the existence of data in the
correct form.
Income Statistics - The alternative to the use of dollar
measures of transactions between industries and worker produc-
tivity in these transactions as the components of the ratio
for deriving employment is to go to a broader more inclusive
accounting system involved in income and product statistics.
In this instance, concern is with all forms of income-producing
activity, investment, and trade as well ad industrial production.
Apportionment of National Employment Estimates - Apportionment
procedure implies a system of analysis which determines how
smaller geographical areas share in estimates previously
prepared for a parent area. Following this general procedure,
two series of employment data may be used in this method:
Bureau of Census employment series or the Bureau of Labor
Statistics employment series.
Estimation bv Direct and Indirect Ratio Procedures - The most
commonly used approaches to estimating future employment in a
locale of interest are to use simple ratio procedures. These
estimate how a particular study area will share in the pro-
jected employment of some larger geographic area. In the
direct local-national ratio approach, percentages of local to
national employment are computed for past decades from census
reports and ordered in a time series. A curve is fitted to
the data and projected to the desired forecast date. The
value of the projected ratio is then applied to the given
estimate of future national employment in order to get future
employment in the study area. The indirect ratio approach
involves a step-down procedure.
The result of any of the analyses is a breakdown of employment by
type, which will be used to calculate the amount of acreage required for
each type of commercial or industrial use.
Population Studies - To be useful, growth potential must be expres-
sed in terms of the population 1t can be expected to sustain 1n terms of
the size of the population, Its composition and characteristics, and Its
spatial distribution. Population size provides an estimate of space
requirements for various land use categories. Investigations Into
31
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population composition assist in estimating residential space require-
ments for various types of dwelling units consistent with family size,
income level, etc. They also assist in determining the amount of space
needed for recreation areas, schools, and other community facilities.
The examination of residential population distribution spatially pro-
vides a basis for the location of the various facilities.
Sound demographic analysis is predicated on accurate population
data. Some basic sources are:
t Complete periodic census enumeration
System of continuous population registration
Estimation of population
Unpublished census data
To be useful in planning studies, this data has to be used in (1)
estimating current population between census enumerations; (2) projecting
future population in the study area.
b. Population Forecasts - Perhaps the single most important population
study for planning purposes is population forecasting. The following
lists some of the most common forecast methods used in small area
studies:
Migration and Natural Increase - This procedure, used exten-
sively by state agencies, is one of adjusting the last census
figures of the locale of interest to reflect changes that have
occurred to date, considering the effects of migration and
natural increase separately.
t Censal Ratio Methods - These are used by both state and city
agencies and include any method utilizing ratio procedures.
The simplest form of the ratio procedure makes a direct step-
down from Bureau of the Census state population estimates to
one particular county or SMSA without examining trends in
other counties. This should be used, however, with caution.
Methods Based on Symptomatic Data - These methods, widely used
by city planning agencies, derive estimates of the current
population by reference to observed trends in data series
which are found to have a close relationship to population
change and for which current data are available. The vital
statistics used include school enrollments, electric meter,
water meter, or telephone installations; registered voters,
etc.
32
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The Cohort Survival Method - This rather complex method
requires an experienced population analyst to execute the
forecast. The method adjusts figures from the last census
forward by age group and sex group year by year to the date of
the forecast, with separate adjustments made for each of the
three major components of population change: death, birth,
and net migration.
Migration and Natural Increase Method - This method starts
with a current estimate of the population, and by introducing
adjustments first for migration and then for natural increase
on a year-by-year basis it develops annual estimates into the
future until the forecast date is reached.
Estimates Based on Forecasts for Larger Areas - This method
employs a previously prepared forecast for some larger geo-
graphical area and by ratio procedures establishes how the
local area may be expected to share in the forecast population
of the larger area.
Estimates Based on Employment Forecasts - Where employment
forecasts have previously been prepared for the study area,
this method is often used as a basis for making population
projections. Using ratios, the method expands future employ-
ment figures to labor force estimates, which are then expanded
to population equivalents.
Mathematical and Graphical Extrapolation Methods - This
includes arithmetic and geometric projections, trend extra-
polation by the method of least squares and estimates based on
the logistic curve.
c. Population Distribution - Estimates of the distribution of future
total population among the various neighborhoods have obvious implica-
tions for the study of residential areas and their community facilities.
Two approaches are commonly used to study the distribution of populat-
ion:
Analysis of daytime population distribution
Residential distribution
Urban Activity Systems - This type of analysis 1s not yet a standard
part of the land use planning process. Traditionally, planning agencies
have gone into land use studies looking at the effects of activity
systems rather than seeking to define and understand activities them-
33
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selves as producers of land use patterns. It should be recognized that
there are no fully tested techniques of analysis for this component.
One method in existence is the origin and destination study done in
transportation planning. In the survey, the respondent is asked to
identify major activities of various members of the household during the
preceding 24-hour period, or he may keep a diary over a longer time frame.
The object of the survey is to be able to identify specific recurrent
behavior patterns which will then enable the planner to make analyses of
space use and travel in order to develop an integrated set of proposals
for land use and transportation to be set forth in the comprehensive
plan.
Urban Land Studies - These studies focus on an investigation of the
features of the land itself. The information obtained describes the
uses for which a particular parcel of land is most suited from a physical
perspective. Specific types of studies that would provide this type of
information include:
Compilation of data on physiographic features
Existing land use surveys
t Vacant land survey
Hydrological and flood potential study
Studies of aesthetic features
For reference, the following types of maps may be used:
t Engineering maps
t Topographic maps
Property or tax maps
This information often indicates constraints on a particular type
of use that could potentially be located on the parcel. It is at this
point in the pre-plan analysis that traditional environmental concerns
can and should be included in the process.
2. The Utility of the Land Use Plan
The information that goes into the development of a land use plan
is of a wide variety. The question then is one of whether these prelim-
inary sources are useful in projecting air quality for the area covered
by the plan.
The basic method for the prediction of future air pollution concen-
tration levels expected from the implementation of a land use plan is
through the use of an atmospheric dispersion model. Models of this type
34
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translate data on emission patterns into patterns of expected concen-
trations for given timeframes. In addition to emissions data, disper-
sion models require meteorological and topographic data in order to make
estimates of concentration patterns. Also, local air quality measure-
ments are needed to evaluate and refine model performance and to specify
confidence limits for the model results.
As mentioned in the introductory portion of the land use discus-
sion, one way of approaching the calculation and projection of emissions
is by dividing sources into three generalized categories--area, line,
and point sources. This is not the only way to classify sources of
pollution, but it does relate well to land use concepts, hence, the
utility of land use data will be evaluated within this framework.
a. Area Sources - In order to calculate this category of emissions, it
is necessary to know:
The location of residential areas
t The types and densities of the housing
General population
This Information, traditionally supplied 1n a general land use plan
and accompanying text, should be adequate to provide a basis for the
calculation of area sources. Population figures will provide a rough
estimate of the number of cars that will be on the local area streets,
which 1n turn can be used 1n the calculation of emissions. The housing
densities and types generally Indicated on the map will g ve an indicat on
of the number of heating units that can be expected. In areas indicated
for potential high density development, emissions from inc nerat,>rs ,f
permitted by law, will also have to be taken into consideration. An
additional iiece of information needed 1n order to calculate emissions
from heating units is the source of energy. This can be obtained from
the utility companies in an area, if the local planning agency has not
alreaOncebtheMurซs of emissions have been determined and the potential
levels have been established, the evaluator must know the Physical
characteristics of the area--particularly variations "JฐPฐ9ซฃy >nd
wind patternsin order to estimate actual pollution leve s. These two
things, of course, will have an effect on whether the pollutants are
dispersed or whether they accumulate over an area. In conjunction with
this, the proximity of significant amounts of open space should be taken
Into account, as 1t has an effect on ameliorating pollution concentra-
tions. Information on open space 1s also presented on the land use map.
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Other components of area source pollution are local commercial and
office facilities (with the exception of regional shopping centers).
These are indicated on the land use map. Greater detail as to the type
of facility can often be gained through an examination of the zoning map
and ordinance which often indicates whether the area is the downtown, or
a community or neighborhood shopping center.
Zoning ordinances frequently differentiate among types of commercial
uses and often require different amounts of parking space be provided.
As previously discussed, the amount of space allocated for commercial
use is based on economic forecasts for the area plus consideration of
population and disposable income. This type of information gives an
indication of the number of cars that will be attracted to an area which
can be related to automotive emissions. Some of these zoning require-
ments may be shifting as a result of the parking plans being developed
as part of the Transportation Control Strategies in many urban areas.
Commercial areas also produce emissions from heating and, possibly,
incineration facilities which should be included in the calculations.
These totals from small scale commercial facilities are then included in
the area totals.
b. Point Sources - The land use plan, through its studies of industrial
demand and the capacity of particular sites for specific industrial
uses, provides an indication of potential locations for industrial point
sources. Depending upon the level of detail included in the plan, the
land use map, particularly the specific map known as the industrial
plan, may reflect the broad industrial categories of light, medium, or
heavy industry. If the map is for a less developed area, it may only
show one general purpose industrial category. In the latter case, it
will be more difficult to determine which areas will, in fact, represent
point sources. It should also be noted that the differentiation into
several industrial land use types does not indicate the process used or
the pollutants emitted.
The distinction made in most zoning ordinances is between light and
heavy manufacturing. The difference between the two is based on the
degree of noxious effectnoise, odor, dust, etc. The regulations
themselves merely list permitted or prohibited industries by industry
type. Many of the newer zoning ordinances, however, are prescribing
performance standards for industry. These define the maximum amount of
noise, smoke, dust, and other external effects that an industry in a
given district may produce. If this type of ordinance exists, the
maximum levels of emissions by zone may already be known.
Performance standards for industrial districts should be viewed
with caution, however, as some jurisdictions to not have the technical
capabilities within the planning or zoning department to enforce the
36
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standards. In addition, the performance standards for air quality
should be reviewed to determine if they do in fact provide for the
control that was intended.
Many areas also do a special industrial survey that locates specific
types of industry in areas with which they are most compatible. In the
comprehensive plan for the City of Philadelphia, the city was divided
into five zones, each with characteristics of particular interest to
industry These zones were then matched with the most suitable indus-
trial type, designated by a three-digit SIC code. This level of specifi-
city while not locating the exact parcel on which a particular industry
is sited does provide approximate areas where pollution concentrations
of a certain type may be expected. If this type of information is
available, it would be as an adjunct to the land use plan and it should
be consulted for use in air quality projections. In any case, indus-
tries in the area should be consulted on any plans that they might have
for the expansion of facilities. Business or real estate pages of local
newspapers often tell of plans for new facilities of industries moving
into the area. Chambers of Commerce or any local or state industrial
development conmissions are added sources of in ormation.
The location of public utilities is usually determined by the
utility companies. The local planning agency obtains the information
from them and reproduces 1t on a land use map. As utl ity companies
often buy up land in anticipation of need, the projections could reflect
this additional knowledge. Depending on the regulations of the state
and whether they are publicly or privately owned, they nay not be
subject to local zoning. In the case where they are not. Pollution from
other sources may have to be reduced in order to meet the standards
where a power plant is to be located in an area.
c Line Sources - The information gained from the land use plan does
mt reaHy contribute to the calculation of line sources of pollution,
which represent emissions from motor vehicles along principal highways
and emissions from aircraft. The studies previously discussed, partic-
ularly the urban activity systems, can contribute Information to Une
source calculations. The basic data sources are the origin and desti-
nation (0-D) studies which locate where people are going so that volumes
of specific roads can be calculated. This, along w th data on speeds,
provide a basis for the calculation of emissions. If 0-D studies are
not available, then data on the capacity of the major roads, plus high-
way speeds can be used to calculate a more generalized picture of line
sources of'pollutlon In an area. Again, 1t should be mentioned that the
comprehensive plan map should be used rather than the land use plan
alone. In the comprehensive plan, the land use and transportation plans
are combined, allowing the evaluator to relate land use and transportation
37
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more precisely. However, the 3-C plan for an area would probably be the
best source of transportation planning information.
3. The Influence of Land Use Planning on Development
In order for a land use plan (or a comprehensive plan) to be useful
as a tool in achieving the objective of air quality maintenance, it must
be supported by an enforcement mechanism. If the planning agency or
local government does not have the legal power to enforce its plan, then
there is no assurance that the plan as developed will ever be implemented.
The knowledge that the plan forming the basis of the projections will be
implemented also increases the validity of any projections that are
made. The power of a plan as part of an overall strategy depends not
only on the ability to enforce it but also on the role of a particular
plan in the total planning picture. If the plan is part of a total
planning process, ranging from the micro, or local, to the macro, or
regional, level, then the information it provides has greater appli-
cability and is more useful.
The following sections discuss both of these elements--the mechanisms
for enforcement and the integrative aspect of the plan.
a. The Mechanisms for Enforcement - Various types of controls can
contribute to the enforcement of the plan. The first level of control
lies with those responsible for the development of the plan and its
subsequent implementation. Generally, the comprehensive plan and the
component land use plan are developed by the planning agency. The land
use plan is a guide, and as such it is not legally binding. The com-
prehensive plan, while not passed as an ordinance, is generally adopted
by the legislative body as a policy guide by resolution. The land use
plan, however, does form the basis for the zoning ordinance, which is
one of the legal mechanisms for ensuring that the plan is implemented.
One problem is that in many places the zoning ordinance preceded the
plan, which makes rational development more difficult. In other cases,
the zoning ordinance may exist without the plan, which means that
development can be haphazard.
As land use planning has traditionally been a local concern, the
greatest powers for enforcement (particularly in the form of zoning)
exist at the local level. As part of the Hackensack study, it was found
that the agencies with jurisdiction over large areasstate, regional,
or countytypically have an extremely limited power base as they are
made up of components which have their own authority in the area of land
use, as defined by state-enabling legislation.
In a study of the Baltimore-Washington area, it was found that the
strengths of land use controls declined as one moved from the central
zones outward. Hence, areas experiencing the most rapid change in land
38
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use are least equipped to control development, as they often have no
zoning. In addition, the planning authority in the region is fragmen-
ted; hence, the patterns of land development have largely been shaped by
the uncoordinated actions of thousands of private developers and multiple
jurisdictions. This means, of course, that the larger the geographic
area covered by the plan and the larger the number of component juris-
dictions, the less likely that the areawide planning agency will have
the tools necessary to enforce it.
Dissatisfaction with the results of local land use controls has
caused many states to adopt statewide or regional approaches to land use
planning. In Alaska, Colorado, Connecticut, Delaware, Georgia, Hawaii,
Maine, Maryland, Massachusetts, North Carolina, Rhode Island, Vermont,
and Wisconsin, either a new state organization or an existing agency is
required to implement some degree of statewide land use planning or
zoning or both, or to carry out some sort of planning and land use
regulation aimed at particular classes of land such as wetlands or tidal
areas. In addition, in some states--such as California with the San
Francisco Bay Community Development Commission or the Tahoe Regional
Planning Agency, New Jersey with the Hackensack Meadowlands Development
Commission, or New York with the Adirondack Park Agency-a regional
agency has been created to deal with some special problems of land use
planning and control. "These various measures are primarily directed at
resource use problems. However, they are significant in the fact that
they do represent a break with past sole reliance on local land use
planning. Some establish state controls that replace local controls;
others provide a combination of state and local controls with the state-
wide concerns clearly dominant. Regional zoning, as differentiated from
state level controls, is much more rare, existing only in Jacksonville,
Florida; Indianapolis, Indiana; and Nashville, Tennessee. This is due
to the consolidation of governments. The statewide and regional approaches
to land use planning and control are, however, too recent to have been
fully tested for either their competence, efficacy, or legal powers."*
It should be noted that although an area may have a plan and a
zoning ordinance to enforce it, there are ways to change zoning and, in
that way, to compromise the land use plan. At the local level, a
legislative body or planning commission may grant a rezoning, or a
zoning board of appeals may grant a zoning exception or variance. This
type of flexibility in the zoning pattern is not necessarily bad, as it
may allow for the introduction of innovation, amelioration of a hardship
or grievance, correction of a mistake in the original zoning, or accom-
~Richard Babcock and David CalHes, "Ecology and Housing: Virtues 1n
Confluct," Mnriprnlzlnq Urhปn Land Policy, edited by Marion Clawson
(Baltimore: Johns Hopkins University Press, 1973).
39
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modation to changed conditions. However, it does decrease the reliability
of projections based on the plan.
The existence of effective land use controls is critical to the use
of land use planning for maintaining air quality. There are presently
several techniques for controlling urban and suburban growth and develop-
ment, including:
Location and timing of public improvements such as roads,
sewers, sewer treatment plants, and water lines.
Lending policies and the restrictions which may be imposed by
private lending agencies and the government agencies that
supervise them or insure their loans
Government subsidies, loans, and other programs for renewal,
development, and redevelopment
Public land use controls--zoning, subdivision regulations,
building codes, health regulations
Tax policies that would encourage the inclusion of environ-
mental objectives into the private decision-making process
Many of these elements are generally delineated in the Capital
Improvements Plan which is the planned budget for 2 to 5 years for
the local jurisdiction.
The following section will discuss zoning in greater detail as it
is the predominant mechanism for land use control. In general, the
power may be transferred by the state, through enabling acts to the
governments at either the local, county, or regional level. Some states
authorize all three types of zoning while others restrict power to the
local level. This decision is generally based on the nature of develop-
ment within the state and the system of land use control that would
appear to be appropriate.
As the concerns of a municipality, county, and regional agency
usually vary considerably, the zoning ordinance, in terms of the provi-
sions and the districts or zones defined, will also vary. Zoning at the
regional level, where it exists, will differ from that of the munici-
pality or the county in that it represents a coordinating function and
usually will be carried out by a body with representation from the
constitutent counties. A regional planning commission constituted in
this fashion may have the authority to prepare various zoning codes and
ordinances for its area, but these must be approved and adopted by the
constituent counties before they have the force of law.
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At the local level, where zoning has been the traditional regula-
ting mechanism, it has been shown that "zoning controls have been of
limited value in guiding new suburban land development. The typical
suburb is either unable or unwilling to enact zoning and other controls
that are strong enough to effectuate a general plan for the area. The
difficulty, however, has been political, not legal. *
Because of the local basis for zoning, the regulations have often
proved obstructive to the development of land use plans at a broader
scale In the past, land use zoning was used by units of local govern-
ment for local ends; hence, when it came to the issue of overall economic
and social development, and the implementation of a metropolitan strategy,
local land use zoning and controls have been notably deficient. The
result has been that development has generally assumed the form of
uncontrolled sprawl. . ปป ,
Gradually, however, there has been a change in the thinking about
land use regulation away from the belief that the purpose of the regula-
tion was for the protection of the commodity value of land. There was a
realization that Important social and environmental goals require more
specific controls on the use that may be made of scarce land resources.
This change 1n attitude is seen not only 1n the new state role in land
use regulation but also in the actions of many local governments.
Modern zoning ordinances typically rely ess on pre-stated regulations,
and require the developers to work with local administrative officials
in designing a type of development that fits more closely into the
surrounding area. Typical of this new direction are planned unit develop-
ment {"PUD) zones which encourage larger scale development in which the
various land uses are arranged and designed according to the comprehen-
sive plan for the specific site as opposed to the traditional lot-by-lot
development. There is also a greater tendency on the part of local
governments to develop more specialized use districts which permit only
those uses appropriate to the geographic area rather than to some
abstract category of uses. This 1s evidence of the growing attempt to
tailor land use regulations to local needs. Finally, and probably most
significantly, for the purposes of planning, there has been a rapid
increase 1n recent years 1n local zoning and subdivis!On regulations 1n
relatively undeveloped areas. Here the concern is with the development
of optimal long-range land use patterns.** This new, more comprehensive
* Modernizing Urban Land Policy, ed. Marion Clawson (Baltimore: Johns
Hopkins University Press, 1973).
**Fred Bosselman and David Callies, The Quiet Revolution in Land Use
Control (Washington, D.C.: Government Printing Office^ 1971).
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approach to zoning may eventually eliminate the over-use of re-zones,
exceptions and variances that tend to distort the patterns.
b. The Integrative Aspect - If the land use and comprehensive plans
are to be useful tools, they should be part of a comprehensive integra-
tive effort to achieve this objective; the broader the base of the plan,
the more likely that it will have some effect. This section will discuss
how the planning agency interfaces with other agencies that might
provide specialized information, as well as the relationship of the plan
to other land planning efforts.
As the concern for the environment is only just beginning to be
incorporated into the comprehensive land use planning process, there has
traditionally been very little need for coordination between the local
planning agency and any existing environmental agencies in the area.
The present concern with expanding the definition of the comprehensive
plan to include environmental considerations, and the requirements of
NEPA and the A-95 Review have probably resulted in an increased level of
interaction between these two groups. In the area of air pollution, the
Hackensack Meadowlands Air Pollution Study has indicated that there is
a lack of a clear distinction between the responsibility of the planner
for the abatement of air pollution problems in the long term and that of
air pollution control officials. It was found that many planners felt
that it is not within their jurisdiction to incorporate air pollution
into the planning process, but rather felt that more effective solutions
could and should be achieved by direct control of emission sources
through the air pollution control agencies and their powers of regu-
lation and enforcement. It would appear that a greater coordinative
effort is necessary so that both strategies are implemented as well as
being mutually supportive. This type of coordination is particularly
important for the control agency so that control strategies can be
closely related to the land use patterns that are developed.
The relationship of a plan to plans of a larger and/or smaller
scale depends to a large extent on the existence of a standard system of
land use categories throughout the area under consideration. There has
been a great problem of comparability of plans as many areas use their
own definitions and collect differents types of data at different levels
of detail. This means that local land use plans cannot always be summed
to produce a regional plan. There are examples where the land use plan
for a region does represent a compilation of the land use plans of the
component jurisdictions. In this case, greater specificity in regional
projections can be gained from looking more closely at the studies that
went into the land use patterns for each of the component jurisdictions.
Because of the variability of the plans, it is difficult to say where
regional and local plans are compatible and where they are not. A
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significant source of conflict may occur in the case where local plans
may reflect community goals over which they have very little control.
For example, a no-growth policy in some local jurisdictions, may be an
appropriate response to the community's ability to provide adequate
facilities and services. However, the local government may possess
neither the regulations nor the will to withstand private development.
On the other hand, especially in less developed areas, local "boosterims"
and wishful thinking may result in vast areas being planned and zoned
for commerce and industry with little support by economic realities.
The evaluator will have to make a decision on a case by case basis.
c. The Planning Document as a Reliable Source of Information - The
degree to which land use plans and zoning maps will be useful to the air
pollution control officers will vary widely from agency to agency because
of the uncertainty that is inherent in the findings and recommendations
contained in planning documents. Some of the factors that must be taken
into consideration are:
A characteristic of almost all plans is that they are not
current. The base year for much of the socioeconomic projec-
tions is information from the census. Techniques for updating
such information vary considerably. Land use inventories are
continuously updated in some agencies, while others may be
several years old. In addition, local actions affecting the
plan may not be reflected on the plan.
Many plans may be so general as to be of little use as a guide
for quantifying and locating future problems in air resource
management. In such cases, the text to the plan may be more
important than the map, as specific development policies or
guidelines may be well articulated. For example, the planning
map may not indicate the location of commercial facilities
while the text may describe locational criteria, service
areas, range of facilities according to function, size, etc.
In the decision-making process, then, the planners would not
be committed to a specific location in advance but would
measure private development proposals against these criteria
set out in the plan.
Planning maps may indicate significant areas for urban develop-
ment which would not necessarily be reflected on the zoning
map. In such cases, the local strategy is to "under zone,"
thereby requiring all potential developers to appear before
local planning and zoning boards and legislative bodies to
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gain plan approval. Under such circumstances, the local
government is likely to have more influence on the type of
development that occurs than if the developer already has the
appropriate zoning. The plan indicates the proposed land use
and provides a guide for zoning action.
4. The Potential for Change
An effective comprehensive plan is not a static document but
rather represents a dynamic process that is regularly updated to reflect
new conditions and objectives. The incorporation of new information
with regard to the relationship between land use and air quality should
be part of the updating procedure. The review process is particularly
important for plans in areas that still developing but are already
experiencing air pollution problems.
The basic guidelines for the development of a comprehensive plan
suggest that the plan should be reviewed annually. "Once a year the
legislators should re-examine the plan and consider possible amend-
ments."* These amendments would normally be initiated by the planning
staff. They would then be screened by the planning commission and
forwarded to the legislators." The importance of the annual review
cannot be overemphasized. This is the main process which is intended to
assure that the plan will be kept up to date. If it is neglected it is
possible that the plan will "ossify" and be ignored. Annual review,
however, is a fairly recent innovation."**
There should be a major reconsideration of the entire plan after
five or ten years. This should provide for an overhaul of the entire
plan, including new surveys, updated forecasts, and the restudy of major
alternatives. The effort expended on this should be similar to that put
into the original plan, and the same general procedures should be
followed. The rationale behind this step is that amendements made at
annual review time will not suffice to keep the plan current after an
extended span of years. Gradual changes (particularly those caused by
re-zonings, variances, and exceptions) may be imperceptible.
The ability to change the plan may not always serve the best
interests of those interested in air quality. That is why it is incum-
bent upon those who have responsibility in this area to review plans at
the operative level and to provide inputs that will provide a basis for
developing plans that contribute more to the achievement of air quality
goals.
* Alan Black, "The Comprehensive Plan," Principles and Practice of
Urban Planning, edited by Goodman and Freund (Washington, D.C.: ICMA,
1963).
**Ibid.
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B THE 3-C PROCESS
The term "3-C process" comes from the Federal-Aid Highway Act of
1962 which requires that all programs for Federal Aid Highway Projects
approved after July 1ป 1965ป in urban areas of more than 50,000 popula-
tion must be based on a Continuing, Comprehensive transportation planning
process carried on Cooperatively in the state and local communities.
1. Current Practice
Generalizations about the process and procedures followed in the
planning studies are very difficult because no two studies follow iden-
tical methods or procedures. All studies vary widely in terms of the
level of detail for specific portions of the study and the analytical
processes used to analyze and evaluate data in the planning process.
While there is considerable variation in the detailed procedures
used in each study, the comprehensive planning process requires that
certain concepts are common to all 3-C planning efforts. These include
evaluations of existing and future economic, population, and land use
data; estimates of future demands for all modes of public and private
transportation; inventories and analyses of all existing transportation
facilities; the development of a comprehensive transportation plan; and
the implementation of a continuing program to monitor and, as necessary,
revise the original transportation plan. The guidelines for implementing
the 3-C process are documented in a series of Policy and Procedure
Memoranda (PPM) prepared by the Federal Highway Administration (FHWA).
Copies may be obtained from the regional FHWA office or the local 3-C
transportation planning agency. (The relevant document in PPM 50-9.)
Figure IV-1 shows the generalized activities of almost all 3-C
planning processes grouped into the following four phases.
Phase I: Data Collection - Various surveys are conducted to
provide a detailed and complete picture of existing travel and
socioeconomic conditions in the study area.
Phase II- Analysis - Analytical methods are used to develop an
understanding of the factors influencing travel demands and
develop procedures for estimating future travel demands and
transportation requirements.
Phase ttt. rm-prastina and Plan Development - In light of the
anticipated land use and land activity, transportation demands
in the study area are forecasted, alternative transportation
strategies are developed and tested, and a final transporta-
tion plan is developed.
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Figure IV -1
pPHASE I
Oat*
Collection
BASIC INVENTORIES
Population
Employment
Land Use
Economic Activity
Laws and Ordinances
Financial Resources
Vehicle Ownership
Labor Force
Income
Social and Community
Values
EXISTING TRAVEL
VOLUME AND
PATTERNS
~ Auto
Public Transportation
ป Truck
ป Taxi
p PHASE II
Analysis
p PHASE III
Forecasting and
Plan Development
, PHASE IV
Implementation &
Continuing Planning
TRANSPORTATION
FACILITIES
Highways
Public Transit
Parking
Terminal and Transfer
Facilities
Traffic Control
Features
Accident Records
MODEL DEVELOPMENT
AND CALIBRATION
Trip Generation
Trip Distribution
Land Use
Land Activity
Mode Split
COMMITTED
TRANSPORTATION
FACILITIES
FUTURE LAND USE
AND LAND ACTIVITY
Population
Land U*e
Economic Projection
Employment
Vehicle Ownership
FUTURE
TRAVEL
DEMAND
ANALYSIS OF FUTURE
ALTERNATIVES
Development
Testing
Evaluation
Selection
SHORT AND
LONG-RANGE
PROGRAMS
CONTINUING
PLANNING
IMPLEMENTATION
Surveillance
* Design Volumes
Public Policy
* Land Use and Land
Re-Evaluation
4^
Activity
Service
Project Planning
Reports
Special Studies
Procedural
Development
46
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, Phase IV: Implementation and Continuing Planning - Under a
continuing program to monitor the planning concepts used in
the development of the original transportation plan, the
transportation strategy developed in Phase III is implemented
and its effectiveness monitored.
The end results of this process are twofold. First, based on a
detailed investigation and analysis of the existing situation, a trans-
portation plan and program can be developed that serves as a common
framework for all agencies charged with transportation systems improve-
ment and operation in the study area. Second, it provides the basic
information and procedures for continually reviewing the appropriateness
of transportation strategy as required by changing events and changing
coimiunity goals and objectives. In almost all major urban areas, the
transportation planning process is in Phase IV, Implementation and
Continuing Planning.
2. Legislative Requirements
The Federal-Aid HighwayAct of 1944 was the first Federal program
to provide regular Federal-aid highway funds for use 1n urban areas
The 3-C planning process in all urban areas with population over 50,000
were established In response to Section 9 of the Federal-Aid Highway Act
of 1962, which amended Chapter I of Title 23, United States Code, by the
addition of a new section, 13A, which states:
It is declared to be in the national interest to encourage and
promote the development of transportation systems embracing various
modes of transport in a manner that will serve the states and local
communities efficiently and effectively. To accomplish this objec-
tive the Secretary shall cooperate with the states, as authorized
in this title in the development of long-range highway plans and
programs which are properly coordinated with plans for improvements
in other affected forms of transportation and which are formulated
with due consideration to their probable effect on the future
development of urban areas of more than fifty thousand population.
After July 1 1965, the Secretary shall not approve under Section 105
of this title any program for projects in any urban area of more
than fifty thousand population unless he finds that such projects
are based on a continuing comprehensive transportation planning
process carried on cooperatively by states and local conmunities in
conformance with the objectives stated in this section.
A description of all Federal, state and local legislation as it
applies to the current 3-C planning process in all urban areas is beyond
the scope of this document. The following is a listing of some of the
47
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major Federal legislation relating the 3-C planning process and air
quality control.
Clean Air Act of 1970 (42 USC 1857(h-7). Purpose: To require the
Environmental Protection Agency to review and comment in writing on
the environmental impacts of any matter relating to duties and
responsibilities granted pursuant to this Act or other provisions
of the authority of the Administration when such impacts result
from a project to which section 102(2)(C) of the National Environ-
mental Policy Act of 1969 applies.
Federal-aid Highway Act of 1970 (23 USC 109). Purpose: To require
the Secretary of the Department of Transportation to issue planning
and design guidelines to be applied to all highway projects which
are approved after the issuance of such guidelines. Under the FHWA
guidelines for Section 109(h) (PPM 90-4), each highway agency shall
develop an Action Plan which describes the organization to be
utilized and the process to be followed in the development of
Federal-aid highway projects from initial system planning through
design.
Section 23 USC 109(h) directs the following:
Not later than July 1, 1972, the Secretary, after consultation
with appropriate Federal and state officials, shall submit to
Congress, and not later than 90 days after such submission,
promulgate guidelines designed to assure that possible adverse
economic, social, and environmental effects relating to any
proposed project on any Federal-aid system have been fully
considered in developing such project, and that the final
decisions on the project are made in the best overall public
interest, taking into consideration the need for fast, safe,
and efficient transportation, public services, and the costs
of eliminating or minimizing such adverse effects and the
following:
(1) air, noise, and water pollution
(2) destruction or disruption of man-made and natural
resources, esthetic values, community cohesion and
the availability of public facilities and services
(3) adverse employment effects, and tax and property
value losses
(4) injurious displacement of people, businesses and
farms
(5) disruption of desirable community and regional
growth
48
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Such guidelines shall apply to all proposed projects with
respect to which plans and specifications and estimates are
approved by the Secretary after the issuance of such guidelines.
The Urban Mass Transportation Assistance Act of 1970 and Section 204
of the Demonstration Cities Act of 1966, further clarified by
Bureau of the Budget Circular A-95. Purpose: To require submis-
sion of all applications for the planning or construction of
facilities using Federal loans and grants to the designated area-
wide agency responsible for metropolitan and regional planning
prior to Federal approval of the application.
These agencies (A-95 Clearinghouse) have the responsibility for
reviewing and commenting upon all applications for Federal assist-
ance for public projects to assure that "to the maximum extent
possible, consistent with national objectives, all Federal aid for
development purposes shall be consistent with and further the
objectives of the state, regional, and local planning."
Air Quality Guidelines for Use in Federal-aid Highway Programs (23
CFR 770) Purpose: To promulgate air quality guidelines for use in
planning and construction of proposed highway improvements con-
structed pursuant to United States Code Title 23. Under these
guidelines, highway agencies planning, constructing, and main-
taining highways pursuant to 23 U.S.C. shall consult with appro-
priate local, state, and Federal air pollution control agencies and
assure that decisions on highways are consistent with approved
State Implementation Plans and that adequate consideration is given
to preservation and enhancement of air quality.
Each 3-C transportation plan must be reviewed annually by FHWA in
order to obtain certification for funding of Federal-aid projects.
Under another FHWA directive (PPM 50-11), an Intermodal Planning Group
must also be established so that planning for all modes of transpor-
tation can be integrated.
All state highway agencies that propose projects for which plans,
specifications, and estimates are approved by FHWA must develop an
"Action Plan" as required under Section 109, Title 23, United States
Code. The "Action Plan" for each state highway agency specifies for
that agency the specific organizational structure and processes to be
followed in the development of Federal-aid highway projects from initial
Planning through design. Therefore, the organizational structure and
proceedings for each agency could vary to reflect the unique situation
of each state.
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Most of the 3-C planning studies are currently in the continuing
planning phase of the study and therefore an "Operations Plan for
Continuing Urban Transportation Planning" has been prepared. Each of
these plans includes:
An outline of the organizational structure for performing
continuing planning, including related committees
An outline of the scope of the continuing planning, with a
breakdown of the functional and financial responsibilities of
all participating agencies
ง A description of the surveillance methodology to be employed
in identifying changes in land development and travel demand,
including assignment of responsibility for providing inputs to
the various models
A description of the land use and travel forecasting pro-
cedures to be utilized, including specific information required
for the various analyses.
A description of any work remaining to be completed on the ten
basic elements (PPM 50-9 paragraph 5) including a schedule for
completion of work.
3. Responsible Agencies
The specific organizational structures for each of the existing 3-C
planning programs vary to some degree. In general, the following types
of committees are formed:
t Policy Committee (sometimes called a Policy Board, Coordi-
nating Committee, Steering Committee, etc.). - This committee
is composed of local elected officials and representatives of
agencies or organizations which have been designated by the
state to provide policy guidance and direction for the study.
In most cases, this conmittee also includes representatives of
the state and FHWA.
Technical Advisory Committee - This committee generally
consists of staff appointed from the various state, regional,
and local governmental agencies participating in the study,
plus representatives of other agencies or organizations who
have special skills in various study items or a special interest
in the transportation planning process. In general, it is the
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responsibility of the Technical Advisory Committee to direct
the study and review all procedures for technical adequacy and
to make recommendations to the Policy Committee.
In some areas, citizens' committees have formed to aid in the
establishment of communications between the technical staff and the
public. These committees also help provide lines of communication
between the public and the governmental units represented on the Policy
Committee.
Generalization about the agencies with statutory authority to
conduct planning studies and adopt plans for their respective areas is
very difficult because of the many variations that exist throughout the
country. In some areas, city planning commissions and/or metropolitan
planning commissions are the only local agencies with this authority.
4. General Description of the 3-C Process
Generalizations about the 3-C planning process are diffcult because
no two studies follow identical working methods and procedures. The
specific type of data collected, the level of detail, and the level of
analysis performed in each study vary to a considerable extent. The
following is a generalized description of the type of data collected and
the types of information developed 1n each of the four phases of the 3-C
process.
a. Phase I: Data Collection - The major inventories conducted in the
initial phase of the 3-C planning process can be combined into three
general classes:
Basic Inventories of Existing Land Use and Land Activity.
Economic Data and Social and Community Values.
The land use and land activity data in general is collected
at the traffic zone level. The number of traffic zones within
a study area vary in total number from several hundred to more
than 4,000 and from a single block to many square miles in
area. Traffic zones are generally small geographic areas in
the more populated areas and large geographic areas in the
outlying, less populated areas.
The land use data Is generally measured 1n acres per zone
and would include the following classifications:
Low density residential
High density residential
Industrial
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Commercial
Agriculture
Public and quasi-public
Vacant
Roads and streets
In some cases the land use codes contained in "The
Standard Land Use Coding Manual," Urban Renewal Administration
and U.S. Bureau of Public Roads, dated January 1965, are used.
Land activity data by traffic zone would include:
Population
Dwelling units
Median and/or mean family income
Auto registration
Employment (by standard industrial classification
code)
Labor force
School enrollment
Existing Traffic Volumes and Patterns
Three basic types of surveys are made to determine the
number, purpose, mode, and time of day trips are made by all
persons and vehicles within, into, out of, and through the
transportation study area. These three surveys are the home
interview, external, and truck and taxi surveys.
In the home interview survey, a sample of all dwelling
units within the study area is selected, and all trips made by
the residents of these dwelling units are recorded. The
sample size varies from 12 percent for small urban areas to
4 percent or less for very large urban areas. The charac-
teristics of the dwelling unit are also recorded in this
survey. These characteristics would include number of persons
in the household, number of cars owned, total household
income, number of persons employed, type of employment, age of
residents, etc. The data for each trip made on a given day by
each member of the household would include the purpose of the
trip, the origin and destination of the trip, the mode of
travel (auto driver, auto passenger, transit passenger, walk
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to work, etc.)- the time the trip began and ended, the number
of passengers in each vehicle, etc.
In the external survey, 25 to 50 percent of all vehicles
crossing the external cordon line of the study area on major
routes on a given day are interviewed. The origin and destin-
ation of the trips, trip purpose, number of persons per
vehicle, type of vehicle, time of interview, etc., are recorded
for each vehicle trip interview collected at the external
cordon.
In the truck and taxi survey, a 10 to 20 percent sample
of all trucks and taxis garaged within the study area is
selected. All trips made by these vehicles on a given day are
recorded. The same type of information collected at the
external cordon line is recorded for each trip.
All of the trip interview data is expanded to reflect the
sample rates, checked and verified so that travel information
reflecting all trips made on a typical day of the survey
period is produced.
In some studies, an on-board transit survey is also
conducted. In this type of survey, a large sample of the
transit riders is interviewed to provide in-depth transit
travel pattern data. Two common types of transit surveys are
direct interviews conducted on the vehicle by trained per-
sonnel and the postcard survey in which questionnaires are
distributed to passengers on the transit vehicle.
From the expanded travel pattern survey data, a detailed
tabulation of the number of trips made between any zones
within the study area by time of day, trip purpose, and mode
of travel is developed.
Transportation Facilities Survey
The third general class of inventories conducted in the
first phase of the 3-C planning process, is a detailed inven-
tory of all transportation facilities within the area to
determine the quantity and quality of the existing transpor-
tation system. Included in the facilities survey are:
Detailed inventory of all- highway facilities which
include detailed tabulation of pavement width and
intersection approach width, all traffic control and
traffic engineering features, as well as extensive
traffic volume data. From this data, existing
levels of service and the capacities of the facil-
ities are determined.
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Detailed inventories of the existing transit system
and its usage. This information would include
location of routes by type of service, transfer
points, frequency of service, and operating charac-
teristics and statistics.
Travel time studies to determine the peak and off-
peak hour speeds on the various segments of the
transportation facilities.
Parking inventories to identify the quantity and
usage of existing parking in the major urban areas.
Location and inventory of major goods terminal and
transfer facilities.
Location and analysis of major traffic generators.
Tabulation and analysis of accident data.
From the facilities survey data, highway and transit
"networks" are developed. These networks are computer-pro-
cessable representations of the existing highway and transit
system operating in the area.
The trip data from the travel pattern survey can be used
in connection with these networks and a system of electronic
computer programs to produce "network assignments." These
assignment procedures and techniques allow zonal trip inter-
change data to be allocated to specific elements of the trans-
portation systemtransit trips to various combinations of
transit routes, auto trips to various highway facilities, etc.
Through these procedures and techniques, it is possible to
approximate the movement of people and vehicles between
various land activities on the existing transportation facil-
ities.
The information available from the assignment techniques
would include vehicle miles of travel, average speeds on
various components of the network, types of trips on various
segments of the transportation facilities, vehicle and person
trip ends by traffic zone, trip length in miles and time for
various types of trips and modes of travel, and the various
area to area movements that result in specific volumes on
individual transportation facilities or combination of facilities,
etc.
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b. Phase II: Analysis - The fundamental purpose of the second phase of
the transportation study is to develop procedures to estimate future
travel demands. The analysis is aimed at obtaining an understanding of
the fundamental characteristics of travel, its repetitiveness, stability,
and regularity. These findings are quantified in a series of mathe-
matical formulas that relate travel demand to the land use/land activity
and transportation system characteristics within the study area. The
analysis is focused on quantifying the answers to specific questions,
such as: What are the relationships that exist within the transpor-
tation study area between the magnitude of trips generated by or attracted
to various Jand activity and the intensity of activity of each location?
What effect does spatial separation of varying land activities have on
the number of trips made between one portion of the study area and
another? What unique patterns exist in the present distribution of
travel demands? How are these patterns explained, and how will they
relate to the transportation demands of the future? How reliable and
how stable are the various methematical formulations used to develop
travel demand estimations? What factors influence the number of trips
made within the area?
These and similar questions must be asked, analyzed, and carefully
answered so that subsequent forecasts will rest on a firm foundation.
The results of this analysis of the base year survey data provide the
basic input for the forecasting phase of the study.
In general, the following type of mathematical models are developed,
calibrated and validated in the larger transportation studies.
Land Activity Models
These models provide a technique for distributing regional
activity levels to small areas and subsequently to drive other
land activity and socioeconomic data related to the activity
distribution. Three general types of activity allocation
models are in current use. They are trend analyses, econo-
metric models and probability-based models. (See Appendix E
for detailed discussion of these models.) It should be noted
that this level of quantified land activity modeling has been
applied in only a few urban areas. Other areas apply the
technique described below.
t Trip Generation Models
These models provide a technique for formulating the
relationships between the trip made in an area and the charac-
teristics of the area such as land use, land activity measures,
or other economic activity measures. Many alternative tech-
niques are used for trip generation. The two most common
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techniques are multiple-regression analysis and cross-classi-
fication analysis. The multiple-regression analysis is a
statistical technique in which multivariable equations are
developed to relate land activity measures within an area to
the number of trips by trip purpose generated by the area.
Cross-classification is a technique in which the tripmaking
attributes of persons or households by trip purpose can be
measured when the changes in two or more other attributes of
the person or household are accounted for.
Trip Distribution Models
Once the zonal trip generation is developed, the trip
distribution models are applied to predict the distribution of
these trips between the zones within the study area. The
three most common trip distribution models are the growth
factor technique, the gravity model techniques, and the
intervening opportunities model. In the growth factor tech-
nique such as the Fratar method, an existing trip distribution
is modified by applying origin and destination factors for
each zone in an iterative process until the desired trip
growth at each zone is reached. This technique is generally
used only in smaller and slowly growing areas.
The intervening opportunity model is a probability
function based on the premise that total travel time from a
point is maximized, subject to the condition that every
destination point considered has a stated probability of being
acceptable. More precisely, the opportunity model states that
the probability that a trip will terminate within some volume
of destination points is equal to the probability that this
volume contains an acceptable destination, times the proba-
bility that this volume contains an acceptable destination,
times the probability that an acceptable destination closer to
the origin of the trip has not been found.
The model operates on inputs concerning the total trips
originating in a zone, the total destinations in a zone, and
an empirically derived probability constant which requires the
average density of trip ends and the trip length.
The gravity model is the most widely used of the three
trip distribution techniques. It is based on the assumption
that trips produced at an origin and attracted to a destina-
tion are directly proportional to the total trips produced at
the origin, the total trip attraction at the destination, an
empirically derived measure for interchange travel between
zones with a given impedance separation, and in some incidences
a socioeconomic adjustment factor.
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Mode Split Models
These models are generally applied to a disaggregate of
total person trips into auto-driver trips, auto-passenger
trips, and transit-passenger trips. Three types of mode split
procedures are the most commonly used: direct transit and
auto trip generation, trip-end modal split models, and trip-
interchange modal split models. In the direct trip genera-
tion, transit and auto trips are developed directly from trip
generation equations. The trip-end modal split model uses the
total person trips produced by the trip generation equations
and produces an estimate of the auto and transit trips prior
to trip distribution. The trip-interchange modal split models
use the person-trip distribution from the trip distribution
models.
c. Phase III: Forecasting and Plan Development - The development of a
transportation plan for the area calls for the preparation and testing
of alternatives and evaluating results in light of the overall goals and
objectives of the communities in the study area. This procedure results
in the recommendation of the regional transportation program based on
the established objectives and standards of all of the communities
contained within the study area. Preparing alternative transportation
plans calls for imagination and judgment as well as a deliberate attempt
to arrange the transportation facilities so that future transportation
strategies can be developed within the limitations of the financial
constraints and community values.
Each of the alternatives tested must be evaluated in light of the
total developments of the area as well as the specific facilities and
their effect on their immediate environment. Existing and planned
renewal and redevelopment areas, housing projects, new subdivisions,
industrial districts, regional parks, open space, etc., must be taken
into account. The selected plan must be as compatible as possible, and
must, to the extent possible, promote other community goals and ob-
jectives, including air quality, energy conservation, and mobility.
The final result of this phase of the planning study is a coordin-
ated and acceptable plan of action to meet the needs generated by the
forecasted land activity, land use, and traffic demand and to provide
the study area with the best solution to the transportation needs that
will exist in the future.
t Forecasting
In the plan development and analysis process carried out
in many metropolitan areas, multiple land use and transportation
plans were considered. In some areas, transportation alter-
natives were developed in relation to a single land use plan
or forecast.
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In those studies in which only a single land use plan was
used, the first step in the forecasting procedure was to
estimate the future land use and land activity for the entire
study area. These forecasts were then disaggregated so that
the employment, population, and other land activity measures
are distributed into the subareas of the region.
The next step in the forecasting procedure is to convert
the estimates of future land use and land activity into
estimates of future travel demand. This is done by applying
the mathematical procedures developed in the analysis phase to
the forecast land use and land activity information. The
result of this procedure is a systematic and detailed estimate
of the location and magnitude of future travel demands through-
out the area. Once the future travel demand is established,
it is studied in relationship to the available transportation
system in the area. In this way, the location of future
facilities and services was developed and evaluated. In the
metropolitan areas where alternative comprehensive land use
and transportation plans are tested, the procedures for developing
alternative land use and land activity forecast varied greatly.
In some studies various land use and land activity con-
cepts such as radial corridor development, multitown (satellite
towns) development, compact city, spread city, linear city,
etc., are selected as general land use and land activity
forms. Forecasts of future land use and land activity were
developed based on these concepts and various alternative
transportation plans. In some studies, the type and density
of activity forecasted for a given area was strongly influenced
by the relative level of proposed transportation facilities
and service available to the area. In other studies, various
combinations of these approaches for developing alternative
land use and transportation plans were used.
Plan Development and Testing
In addition to the variations in developing various land
use and land activity forecasts, several transportation
alternative concepts were used in most studies to develop and
test alternative plans. These included transportation varia-
tions such as highway-intensive plans, freeway-intensive,
radial systems, grid systems, minimum improvement, maximum
improvement, etc., as well as various combinations of these
network concepts.
In testing and evaluation of each of the land use plans
and transportation alternatives, many types of procedures and
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techniques were emphasized. One generalized procedure,
common to almost all studies, involves the development of
future travel demands, the assignment of these travel demands
to the transportation network, and the evaluation of the
assigned volumes relative to some performance measures.
In addition to the evaluation of the performance of a
single land use and/or transportation plan, comparison of the
alternatives was also made in most areas. In many studies,
comparisons and evaluations to a no-improvement alternative,
in which only the existing transportation facilities and
service were included in the network, were also made.
Performance measures used in these evaluations at both
the regional and subregional levels include total trips by
persons and vehicles by mode and purpose; travel times and
cost by mode and trip purpose; vehicle miles and vehicle hours
of travel; average speed by mode and facility type; measures
of system capacity versus travel demand by mode and facility
type; trips to and from major subareas (such as the CBD) by
mode and trip purpose; average length by mode and trip pur-
pose, etc.
Another type of system evaluation commonly used was an
economic analysis such as the benefit-cost analysis. In this
type of analysis, facility cost and transportation cost by
both the public and private sector were estimated. Comparisons
were then made of the benefits derived from decreased travel
distance and travel time and the cost of providing the proposed
facilities and service.
Performance measures of accessibility provided by the
highway and/or transit system to various subareas as well as
general measures of accessibility to population, employment,
and other land use activity were also developed by some
studies. Many forms of analyses were developed in various
studies to evaluate the impact of various land use plans and
policy elements. Incorporated in many of the studies were
evaluations of the impact of various public policies regarding
the transit systems, parking facilities, sewer policies, open
space, land use control for commerical and industrial develop-
ment, etc.
From the analysis of alternative land use and transpor-
tation plans, one of the alternatives or a next plan developed
from several alternatives was selected for implementation.
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d. Phase IV: Implementation and Continuing Planning - Most of the 3-C
transportation studies are complete through the first three phases of
the study process and are now in the implementation and continuing
planning phase of the study.
5. Data Sets and Formats
Many reports, technical memoranda and tabulations, and summaries of
data are produced through the 3-C Planning Process. The 3-C Planning
Process dates back to the early 1960s in most urban areas and was used
in some studies begun in the mid-1950s. In that time period, there have
been many studies and updates of inventory data. Also, significant
changes have taken place in the technology used in the planning process
so that the original models developed in many studies have been revised
and reapplied to develop more reliable future forecasts and provide
better analytical data for the evaluation of transportation problems.
Because of the dynamic nature of the planning effort in many areas,
problems can occur in the evaluation of published reports and tabula-
tions of data. In many cases, detailed documentation of current prac-
tices and forecasts, which may differ substantially from those previously
documented, are either not available or exist only in the form of tech-
nical memoranda with limited distribution. Thus, efforts to utilize
transportation planning data must be accomplished through staff of the
local 3-C planning agency.
a. Reports
Annual Report - Each of the 3-C studies is required to prepare
an annual report. This report contains a summary of the
current planning activity and the surveillance program as
developed in the operations plan for the individual study.
Reports are also developed for many of the study areas when
major reviews and plan revaluations are made. The major
review is generally performed at five-year intervals and the
plan reevaluation at ten-year intervals unless the annual
review indicates a need for more frequent examination.
The Operations Plan - This plan for each study in the con-
tinuing phase describes the organizational structure, scope of
the continuing planning and the methodology and procedures
used in the study. The operations plan is revised when
significant changes occur in the study operations.
The Unified Work Program - This report is developed annually
by most 3-C study areas and describes the allocation of funds
for the planning activity.
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The Action Plan - Each state has developed an action plan
describing the organizational structure and processes to be
followed in the development of Federal-aid projects from
initial system planning through design.
Study Reports - In addition to numerous technical reports
generated by each study, several summary reports are typical
to most studies:
Base Year Findings Report - This report presents in
a summarized and graphic form the results of the
data collection phase of the study.
Model Development Report - This report contains a
description of the development and validation of the
models used in the study.
Forecast Report - This report contains a description
of the land use, land activity and travel forecast.
Transportation Plan Report - This report describes
the procedures used to develop and evaluate the
various transportation and land use alternatives,
and the resulting plan or plans developed from this
analysis.
Capital Improvements Plan - This is the short and long range
dollar budget for implementing each phase of the plan. It is
from this budget, when adopted, that state and local funds are
allocated for transportation projects.
b. Computer and Other Data
Most of the 3-C studies have compiled the following types of data:
Existing and Forecast Land Use and Land Activity Data by
Traffic Zone - In most studies, there is a tabulation of the
base year data described previously. This data is updated
under the procedures described for the operations land. The
forecast data is generally developed for short-term projec-
tions and for the target or design year. The short-term
projections would be a 5 or 10 year projection and the long-
term projection for 15 to 20 years.
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Transportation Facilities - Base inventories of the existing
highway and transit facility and travel demand are also up-
graded annually under the continuing phase of the transpor-
tation study. This would include traffic counts on highway
facilities, patronage, and revenue data for the transit system
and an update of the inventory of transportation facilities.
In addition to this information almost all studies will have
developed short-term and long-term travel demands. These area
travel demands, based on the forecasted land use and land
activity data, are assigned to future transportation networks
to provide approximations of the future demand for all major
transportation facilities. Data available from these proce-
dures would include area-to-area travel demand by trip purpose
and mode, total travel demand generated by subareas, vehicle
miles and vehicle hours of travel by facility type and sub-
areas, total travel demand on each segment of the highway and
transit system and the travel speed on each segment of the
highway network.
This generalized discussion is intended to serve as a guide to air
pollution control personnel who may be participating in air quality
maintenance planning. It should be recognized that in many urban areas
the data required for air quality maintenance planning may not be
readily available, or will require reformatting, or even reanalysis. It
may be expected that, over time, the 3-C process will include compatible
inputs, analysis, and products that can be used for comprehensive
environmental planning.
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Meshenberg, Michael J. Air Zoning: An Application of Air Resources
Management. Chicago, Illinois: American Society of Planning
Officials, July 1966.
Northeast Illinois Planning Conmission. Managing the Air Resources in
Northeast Illinois. Chicago, Illinois: Northeast Illinois Planning
Commission, 1967.
Office of Management and Budget, Standard Industrial Classification
Manual. Washington, D.C.: U.S. Government Printing Office, 1972.
Pelle, William J., Jr. "Bibliography on the Planning Aspects of Air
Pollution Control," Washington, D.C., 1964. (mimeographed).
Rydell, C. Peter and Collins, D. "Air Pollution and Optimal Urban Form."
Paper presented at the 60th Annual Meeting of the A1r Pollution
Control Association, Cleveland, Ohio, June 11-16, 1967.
65
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Rydell, C.P. arid Schwarz, 6. "Air Pollution and Urban Form: A Review
of Current Literature." Journal of the American Institute of
Planners, March 1968.
Sterm, Arthur C., ed. Air Pollution. Vol. I: Air Pollution and Its
Effects. New York: Academic Press, 1968.
Studholme, Edward Dickinson. "Prospective Effects of Motor Vehicle Traffic
on a Portion of the Urban Interstate Highway SystemAn Environmental
Planning Analysis." Unpublished Master's Thesis, The George Wash-
ington University, 1972.
The Urban Land Institute. The Community Builders Handbook. Washington,
D.C.: Urban Land Institute, 1968.
U.S. Environmental Protection Agency. A Guide for Reducing Air Pollution
through Urban Planning. Washington, D.C.: U.S. Government
Printing Office, 1967.
"Maintenance of National Ambient Air Quality Standards."
Federal Register, Vol. 38, No. 116, June 18, 1973, 15834-15837.
"Preparation, Adoption and Submittal of Implementation
Plans." Federal Register. Vol. 38, No. 74, April 18, 1973, 9599-9601.
"Prevention of Significant Air Quality Deterioration."
Federal Register, Vol. 38, No. 135, July 16, 1973, 18986-19000.
"Requirements for Preparation, Adoption, and Submittal
of Implementation Plans." Federal Reaister. Vol. 36. No. 158. Au-
gust 14, 1971, 15486-15506.
VanNest, William J. and Hagevik, George H. Air Pollution and Urban
Planning: A Selective Annotated Bibliography. Monticello, Illinois:
Council of Planning Librarians, February 1972.
Voorhees, Alan M., Barnes, Charles F. Jr., and Coleman, Francis.
Traffic Patterns and Land Use Alternatives. Presented at Highway
Research Board 41st Annual Meeting.
Voorhees, Alan M. Practices and Trends in Transportation Planning.
Presented at the Highway Management Institute, March 1969.
Williams, James D. and Edminsten, Norman G. An Air Resource Manage-
ment Plan for the Nashville Metropolitan Area. Washington, D.C.:
U.S. Department of Health, Education and Welfare, September 1965.
66
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Willis, Byron H. "The Hackensack Meadowlands Air Pollution Study Summary
Report." Submitted to the State of New Jersey Department of En-
vironmental Protection by Environmental Research and Technology,
Inc., August 1972.
Willis, Byron H., Gaut, Norman E., and Newman, Elliot. "AQUIP--An Air
Quality Evaluation System for the Planning Community," Paper pre-
sented at the 64th Annual Meeting of the Air Pollution Control Asso-
ciation, Atlantic City, New Jersey, June 27-July 2, 1971.
Willis, Byron H. and Mahoney, J.R. "Planning for Air Quality." Paper
presented at Confer-In '72 of the American Institute of Planners,
Boston, Massachusetts, October 1972.
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APPENDIX A
PROJECTING AND ALLOCATING EMISSIONS AND/OR
AIR QUALITY
-------
PROJECTING AND ALLOCATING EMISSIONS AND/OR
AIR QUALITY
The following sections describe the methodology for projecting and
allocating emissions and/or air quality in AQMAs. This approach main-
tains the identity of the individual source types contributing to the
future air quality, so that control measures developed as part of the
maintenance plan can be directly related to their impact on the future
source types and distribution. The methodology assumes:
The future emissions of all source types can be projected
using available economic projection factors on a county basis.
A methodology will be available to project county emissions by
these source types for the years 1975, 1980, 1985 (Booz-
Allen/EPA).
The projected county emissions can be allocated to a more
detailed spatial distribution required by some air quality
modeling techniques using traditional local planning inputs.
The allocation method for each source category is discussed in
the following sections.
The projected emissions can be related to ambient air quality
using available modeling techniques (to be defined by EPA).
A. UTILIZING TRADITIONAL PLANNING DATA AND CONCEPTS
Methodologies for projecting countywide emissions and methodologies
for relating emissions to ambient air quality are to be reproduced in
detail elsewhere In the Guidelines Series. The following discussion
will focus on procedures for utilizing traditional planning data or
concepts to redistribute or allocate projected emissions to a subcounty
area.
The local 3-C planning agency is a prime source for land use and
transportation data and should be requested to assist 1n the collection
and application of the best available data. In many regions, a subarea
A-l
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plan (county plan) may contain more detailed data to evaluate problem
areas than the composite regional plan. However, these detailed data
may be based on assumptions that conflict with the regional 3-C plan.
Before proceeding with these data, the 3-C planning agency should be
asked to comment on the uncertainties in them.
B. DETAILED METHODOLOGY
The following paragraphs discuss the detailed methodology for
projecting and allocating emissions and/or concentrations of: total
suspended particulates (TSP); and sulfur dioxide (S02); and carbon
monoxide (CO); total hydrocarbons (HC; oxides of nitrogen (NO ); and
photochemical oxidants (0 ).
X
1. Particulates and Sulfur Oxides
Figure A-l illustrates the methodology for projecting and allocating
emissions (concentrations) of total suspended particulate and sulfur
dioxide. As discussed in the general work flow plan, the concept of the
methodology is to maintain the identity of the significant sources to
the extent possible so that their individual and composite impact on
emissions or air quality can be determined. Therefore, the methodology
diagram illustrates that the emissions projections and emissions allo-
cations of area sources, power plants, and point sources are to be
performed independently. All of the point and area sources emissions
may be displayed on a base map of the AQMA (or county). If an air
quality projection method is available which accepts all such sources
(see Appendix D), the allocated emissions can be immediately input to
such a model to determine air quality for the time period of interest.
If such a model has not been calibrated for the study area, a simple
Gaussian-type model can be used to independently calculate the point
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FIGURE A-1
TOTAL SUSPENDED-PARTICULATES
AND SULFUR DIOXIDE
1980, 1985
EMISSIONS AND AIR QUALITY
A-3
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source concentration isopleths and the area source concentration iso-
Pleths. These can be superimposed to produce the composite concen-
tration isopleths for the area.
A more detailed discussion of the emissions projection and allo-
cation methods for each source type follows.
3^ Area Source Emissions Figure A-2 illustrates the steps of the
Area Source Emissions Projection and Allocation Procedure."
S.teRs, 1-3 - A methodology for projecting area source emissions on
a county basis for 1980 and 1985 is currently being prepared under a
contract to EPA by Booz-Allen. The 1970 NEDS data is used as base
year values. The countywide totals by type are then factored to
1980 and 1985 based on expected county growth rates. In the absence of
county growth rates by type for the forecast years, BEA statistics
for the area can be used. Since the existing data (1970) does not
reflect the emission reductions expected to result from the SIP, the
1980 and 1985 totals will be reduced to compensate for the reductions
expected.
Steps 4-5 - These area source emissions can be distributed to a
grid network within the county using the CAASE (Computer Assisted Area
Source Emissions) technique and software package currently being prepared
for EPA. This technique would have to be modified to project the demo-
graphic distribution factors using available land use plans or associated
socioeconomic data. If time or funds do not permit this modification,
the basic output for the existing inventory and conditions can be adjusted
manually to reflect growth and development plans or data.
Since most available land use forecasts are generalized, some
judgements must be made regarding the nature of new development indicated.
To allocate the projected countywide total emissions to the grid system,
A-4
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FIGURE A-2
AREA SOURCE EMISSIONS AND AIR QUALITY
A-5
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changes in the existing land use must be quantified. The first task
should be to determine where new commercial, industrial, and residential
development most likely will occur within the forecast period. This
should be indicated on the grid system used. Next, the total number of
grids within each county by land use type should be determined for both
1980 and 1985. For residential and commercial emissions, total emissions
can then be averaged over total area. While this will tend to neglect
densities of development, it should be suitable for identifying approxi-
mate ranges of emissions.
To allocate industrial area source emissions, two rates should be
developed for each county; one for light industry and one for heavy
industrial development. Many areas differentiate between these two
categories on their land use plans. Since this is not always true, some
judgement will be required to indicate what type of development may be
expected. In lieu of observed rates for varying industrial types, a
ratio of 5 to 1 should be sufficient to identify problem areas. Thus
while one grid of light industry might be allocated one ton of TSP per
year, an adjacent grid of heavy industry would receive five tons per
year.
Step 5 ' Wherever Possible, the new source emissions should be
distinguished from those sources which existed in 1975 (and their growth
to 1985) for the purpose of maintenance measure evaluation. This step
is only applicable if county level growth rates have been used to project
the emissions. If BEA statistics are used, new sources will normally be
underestimated 1n outlying areas and overestimated in the urbanized core
of the AQMA. This is primarily attributable to the low existing
pollutant levels in the areas within AQMAs where the growth potential is
most prevalent.
Steps 6-7 ' Area source concentration isopleths can be computed
using any of several Gaussian-type diffusion models that accept the grid
A-6
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network data produced by CAASE. These include AQDM and Grifford-Hanna.
The modified "roll-back" or "roll-forward" technique may also be used
where air quality data is available. EPA is currently preparing guide-
lines on available air quality projection techniques.
b. Power Plant Emissions Figure A-3 illustrates the steps of the
Power Plant Emissions Projection and Allocation Procedure.
Steps 1 and 2 - Because of power plant siting regulations and
detailed permit requirements, the location and general characteristics
of proposed power plant emissions are known approximately ten years in
advance. Source growth and control factors can therefore be obtained
for this category.
Step 3 - Existing power plant emissions and their projected growth
should be distributed independently from the new source emissions for
the purpose of control plan development. Although the new power plant's
location may already be planned, it may affect the location of other new
major sources in the area.
Steps 4 and 5 - Since power plant emissions come from very tall
stacks, these sources must be considered independently of other point
source types. Proportional air quality modeling techniques should not
be applied to power plant emissions unless some factor is included to
account for the effect of emission height on local concentrations. EPA
will recommend the diffusion modeling techniques to be applied. In many
cases, existing power plants have already been modeled.
c. Point Source Emissions' Figure A-4 illustrates the steps of the
Point Source Emissions Projection and Allocation Procedure.
Steps 1. 2, and 4 - A methodology 1s currently being prepared for
EPA to project emissions on a county basis. The projected emissions
A-7
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FIGURE A-3
POWER PLANT EMISSIONS AND AIR QUALITY
A-8
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FIGURE A-i>
POINT SOURCE EMISSIONS AND AIR QUALITY
A-9
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will be based on industrial growth statistics by source category (such
as SIC code or SCC code). For plan preparation purposes, the total
emissions must be separated into at least the following categories:
Existing sources - current (1975)
Existing sources and growth at existing sources (1980, 1985)
New sources (1980, 1985)
Therefore, a survey procedure is suggested (Steps 3, 5, 6, and 7)
to determine the expected growth at existing sources.
Steps 3, 5, 6, and 7 - Survey existing sources to determine the
f ol 1 owi ng:
Existing operating capacity
Existing operation as a percentage of maximum existing oper-
ating capacity
Expansion plans (next 10 years)
t Control plans
Opinion of possible growth of this particular industry type in
the area and where in the area (county) the resources are
available to support such a new facility
The Plan Revision Management System (PRMS) has a software package
which will sort the National Emissions Data System (NEDS) inventory data
for an AQCR to determine those sources which contribute 80 to 90 percent
of the total emissions for a given pollutant. This list can be further
sorted by county and source type (SIC code or SCC code) to provide a
list of existing significant sources to be surveyed. Experience with
several AQCRs for which such lists have been compiled indicates that
there are probably no more than 30 to 50 such sources for any one pollu-
tant in an AQMA and probably no more than three to five such sources for
A-10
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any one county. Therefore, it appears feasible to perform such a
survey within the time constraints of AQMA plan preparation. It is
recommended that a local planner or regional planning agency perform the
actual survey. Item 5 of the survey will then assist the planner in
distributing the new sources as proposed in Step 8.
Items 1 to 4 of the survey can be used to estimate the fraction of
the total emissions (from Step 4) which are due to existing sources and
their attendant growth. This can be subtracted from the total projected
emissions (Step 4) to obtain the new source emissions (Step 6).
Steps 8 to 11: Emissions Allocations - The existing point sources
and their attendant growth (Step 7) can be located by referencing the
NEDS Inventory (Step 9). The stack parameters associated with each
source should be retained (see NEDS) for input to the air quality pro-
jection model (Step 12).
The "new source" emissions (Step 6) can be distributed by one of
the following methods using the survey results (Step 3) and land use
plan data or techniques:
a A weighting system that evenly distributes the emissions among
those industrial zones (see county zoning plans) which in the
opinion of the survey and the regional planning agency would
be most likely to attract new manufacturing.
b. A weighting system that evenly distributes emissions based on
an "industrial growth plan." Some urban areas, for example
Philadelphia, have prepared industrial growth plans to en-
courage new development in the most "appropriate" areas. Such
plans may be used to locate new sources if it appears reason-
able to the planning agency.
c. An informal emissions allocations procedure further restricting
the location of significant sources to those "most probable"
location areas in (a) and (b) above not projected to be sig-
nificantly close to the standards levels before inclusion of
the new source emissions. The basic assumption behind this
A-11
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allocation procedure is that new sources will not be allowed
to locate in an area such that the provisions of the AQMP will
be violated.
The rationale for distribution of emissions using this system would be
as follows:
New point source emissions will be a small fraction of the total
emissions contributing to the ambient concentrations in the area. New
source performance standards will control the amount of emissions from
any one source and will discourage the location of "heavy polluters" in
urbanized areas. If total point source emissions are projected by
source category in a county and the projected emissions of existing
sources is subtracted from this total by source category, the residual
emissions (those due to new point sources) will indicate the amount of
new source emissions which could come from any one source within that
category. For example, if S02 residual emissions for the SIC code
containing sulfuric acid plants is greater than the allowable emissions
process weight curve, there will be more than one new source of S02 to
locate in the county. An examination of the planned industrial areas in
the county which would have the facilities to support a new, major S02
source would probably reveal that no more than two or three sites could
possibly support a new "heavy industry" of this source type. The con-
centration isopleths for all area sources, power plants, and existing
point sources should be superimposed to produce the concentration pattern
"due to all sources except the possible new significant source(s). All
areas within a given percent the standards could be identified as "potential
problem areas." Two conditions could then be evaluated the "most probable"
and the "worst-probable" case.
The "most probable" case would be that the new sources will not be
placed in any potential problem area. The emissions could then be
A-12
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evenly distributed to those sites which are not in problem areas. The
"worst-probable" case would be to allocate the emissions to one or more
problem areas and determine if the standards will be exceeded. If the
standards are exceeded by this case, the AQMP could provide a control to
prevent the growth from occurring at this location.
Steps 12 and 13: Air Quality Projection - It may not be desirable
or necessary to complete the detailed emissions allocation procedures in
Steps 8 through 11 above if new point source emissions are insignificant.
The total point source emissions (Step 4) and the simplified distribution
system for new sources could be used as input to an air quality model.
2. Carbon Monoxide. Hydrocarbons, Oxides of Nitrogen and Photochemical
Oxidants
Figure A-5 illustrates the steps of the Methodology for Emissions
Projection and Allocation of Carbon Monoxide, Total Hydrocarbons, Oxides
of Nitrogen and Photochemical Oxidants. The initial designation criteria
implies that most AQMAs designated for any of these pollutants will be
Transportation Control Plan (TCP) AQCRs. It is also assumed by the
definition of a maintenance plan, that the TCPs will be able to meet the
standards by the 1975 or 1977 attainment dates. In the transportation
control plan AQCRs, mobile sources of these pollutants currently account
for 60 to 90 percent of the total emissions of CO, HC, and NO . There-
fore, a fourth source type category projection and allocation scheme is
added to the methodology requirements. However, area sources, power
plants, and points sources are still retained as significant sources of
emissions.
If CO standards are met by 1975 or 1977, then they will not be
exceeded by 1985 on a regional basis. This hypothesis is based on a
comparison of the emissions control curve, which shows an 80 to 90
A-13
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FIGURE A-5
CARBON MONOXIDE, HYDROCARBONS
ANP "OXIDES OF NITROGEN
1980, 1985
EMISSIONS AND AIR QUALITY
A-14
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percent reduction in vehicle emissions between 1980 and 1985, and the
maximum regional growth estimates for any urban area (-5 percent).
These pollutants may exceed the standards in sub-AQCR areas where
urban congestion and/or traffic congestion is projected to occur at
levels exceeding the regional growth rates.
If mobile source emissions are reduced by between 50 and 90 percent
of their baseline (1970-1972) emissions levels, and coincidentally, area
source or stationary source emissions are not controlled, these secondary
source types may represent between 30 and 60 percent of total emissions
by 1980 or 1985. Therefore, problem areas within the AQMA may represent
mobile source congestion, or uncontrolled stationary source growth, or
a combination of source problems.
The emission projection and allocation metnods tor area, point, and
power plant sources above are still applicable. However, since the
standards for CO and oxidants and the guidelines for hydrocarbons are
short-term values, the air quality projection steps must incorporate a
means of relating the annual emissions and/or concentrations to short-
term values. This may require that the emissions projections be converted
to short-term (i.e., for CO1-hour and 8-hour, and for hydrocarbons
6:00 to 9:00 average values).
a. Mobile Source Emissions In the discussion above it was noted
that problem areas due to mobile source emissions will be found only
where congestion or unaccounted for growth occurs. This is due to the
significance of the speed factor which increases greatly as low average
speeds or congestion is approached. This indicates that mobile source
problems will be "hot-spot" problems. The data base and allocation
methodologies must be capable of determining these "hot-spots." In most
cases, the data base and projection techniques are available to perform
A-15
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these evaluations, however, it is likely that the techniques are too
costly and time consuming to be performed within the timeframe for air
quality maintenance and plan development.
In the following discussion of methodology some simplified techniques
are suggested for obtaining the required projections, however, the
assumptions upon which the analysis is based should be carefully con-
sidered.
It is recommended that these assumptions be reviewed on an annual
basis and should they become invalid, the AQMP should be flexibile
enough to incorporate these changes.
Figure A-6 illustrates the steps of the basic concept of the
Mobile Sources Emissions Projection and Allocation
Steps 1 to 3 - The mobile source inventory should be available in
Appendix C format (40 CFR 51) for all transportation control plan areas.
This inventory must be allocated to the AQMA(s) and divided into motor
vehicle emissions and other mobile source emissions such as airports and
significant centralized transportation systems.
Step 4 - In all AQMAs that exceed the population of 50,000, a 3-C
transportation plan is available in some form. The data available in
these plans is discussed in detail elsewhere in this report. The
significant data element of this plan for vehicle emissions is the
traffic network assignment. In order to accurately assess the "hot-
spot" problems, the detailed network assignment for the year of interest
must be obtained. This may not be available and some method of inter-
polation between available data and the year of interest must be used.
However, linear interpolation would not be reliable between, for example,
a 1970 network and a year 2000 network because of the change in dis-
tribution pattern expected. A procedure for obtaining an approximation
for the year of interest is as follows:
A-16
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FIGURE A-6
CO, HC, AND NOx
1980, 1985 MOBILE SOURCE EMISSIONS
PROJECTION AND ALLOCATION PROCEDURE
A-17
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Obtain the network assignment which most closely relates to
the year of interest
Request the 3-C transportation agency to determine whether
sketch planning techniques or macro-level analysis techniques
could be used to estimate the changes in the network to the
level of accuracy desired for analysis. At the regional
level, the following tools have been utilized to estimate
macro-scale changes:
"A Methodology for Estimating Macro-Level Travel Demand
in Baltimore Metropolitan Area" - a method presented
for calculating regional VMT for a number of transportation
actions. The results indicate that the greatest change
in VMT is brought about through restraints and non-
capital intensive actions. The tool was developed for
EPA, working cooperatively with the 3-C process in
Baltimore.
"CAPM (Community Aggregate Planning Model), Federal
Highway Administration, unpublished report (1973)," - a
method of calculating regional VMT given an estimate of
vehicle trip end density, arterial and freeway spacing,
and speed limits. The calculations can be done by hand,
but a computer program is available to do the work in a
few seconds. The tools have been used in a few urban
areas. There are some problems with the mode choice
component of the model.
If the sketch planning techniques are not appropriate, request
the 3-C planning agency or other professional familiar with
both the regional characteristics and the tools to be applied,
to prepare a link-node assignment for the year of interest,
suitable for input to an emissions or air quality model.
Step 5 - Project the airport emissions for the year of interest
using the land use plan or current information available from the 3-C
planning agency, such as the FAA grant application.
Step 6 and 7 - Several emissions models have been used to calculate
emissions directly from network data. These include the APRAC 1A (SRI
model) and the SAPOLLUT model (which is not part of the Federal Highway
A-18
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Administation (FHWA) program battery). The TASSIM study which was
reviewed for its utility in this methodology is described in Appendix C.
This study method simplified the traffic network before calculating
emissions. The assumptions inherent in this simplification may greatly
affect the accuracy and spatial distribution of emissions resulting from
its application. However, TASSIM is readily available and fairly simple
technique to apply.
Step 8 - Air quality projection techniques are available for
carbon monoxide and include such models as APRAC 1A (SRI), Gifford-
Hanna, and TASSIM. Other modeling techniques are currently under
review by EPA and will be described in the guidelines for analysis.
Air quality projection techniques for reactive hydrocarbons, NO ,
X
and photochemical oxidants are poorly defined at this time and are not
available for subarea analysis. The forthcoming EPA guidelines will
provide some interim method for analysis until the current studies of
these reactive pollutants are available and generally applicable.
Regionwide rollback of total hydrocarbon emissions appears to be the
only available technique for oxidant and N02 evaluation.
A-19
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APPENDIX B
A REVIEW OF THE STATE-OF-THE-ART QUANTIFYING THE
RELATIONSHIP OF LAND USE AND TRANSPORTATION TO AIR QUALITY
-------
A REVIEW OF THE STATE-OF-THE-ART QUANTIFYING THE
RELATIONSHIP OF LAND USE AND TRANSPORTATION TO AIR QUALITY
A. REVIEW OF RELATED STUDIES
If the process for relating land use and transportation plans to air
quality is to be used to prepare or evaluate the air quality main-
tenance plans, all of the techniques and data required to provide the
information described above must be available and generally applicable*
A review of several studies or models that have attempted to relate land
use and/or transportation plans to air quality was performed to determine
the utility of the study techniques or results to the preparation of
air quality maintenance plans. These studies include:
The Hackensack Meadowlands Air Pollution Study (Environmental
Research and Technology)
Air Pollution/Land Use Planning Project (Argonne National
Laboratories)
A Report on Guidelines for Relating Air Pollution Control to
Land Use and Transportation Planning in the State of California
(Livingston and Blaney)
The Transportation and Air Shed Simulation Model (TASSIM)
Reports, DOT-OS-30099 and S0T-0S-20099-4, March 1974.
(Harvard University)
0 The Baltimore Regional Environmental Impact Study (BREIS),
March 1974)
The Hackensack Meadowlands Air Pollution Study was developed by
Environmental Research and Technology, Inc., to provide a general
methodology for considering air pollution in the formulation and evalua-
tion of alternative urban plans and applied the methodology to alternatives
B*1
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developed for the New Jersey Meadowlands area. The Air Quality for Urban
Industrial Planning (AQUIP) model was developed; this model uses a set
of submodels requiring detailed data for land use, emission factors,
meteorology and ambient air quality.
The Air Pollution/Land Use Planning Project was completed by the
Argonne National Laboratory. The objective was to investigate the utility
of various land use parameters in describing the air quality impacts of land
use plans, using the Chicago region as a test. The tests were made for
manufacturing and residential/commercial land uses.
Guidelines for Relating Air Pollution Control to Land Use and Trans-
portation Planning in the State of California were developed by Livingston
and Blaney. The purpose was to integrate the goal of achieving and main-
taining air quality with the land use and transportation planning process
in California metropolitan regions. The primary concept is one of allo-
cating allowable emissions to subareas within air basins.
The Transportation and Air Shed Simulation Model (TASSIM) was
developed at Harvard University. The study was designed to develop a
model that would integrate existing urban transportation models, vehicle
emissions factors, and a simple air diffusion model to analyze air quality
effects of various transportation policies. The model was applied and
calibrated in the Boston area, using a district level "spider" network,
representing the average characteristics of the facilities represented
by the network.
The Baltimore Regional Environmental Impact Study (BREIS) evaluated
the environmental impacts of the proposed urban interstate highway system
in the City of Baltimore. All environmental analyses were performed
including air quality. The study was performed by Alan M. Voorhees and
Associates, Inc. for the Interstate Division of Baltimore City.
B-2
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The review of each of these studies is given in Appendix C of this
report. In general, no generally applicable model or technique is
available that will meet all of the information requirements discussed
above. The models or studies listed above could serve as a core to a
community specific process or model. However, all such models require
extensive data bases which are not generally available.
B. SUMMARY AND CONCLUSIONS
The review of the studies and methodologies listed above, and the
techniques described suggest the following conclusions regarding the
state-of-the-art in relating land use to air quality and its application to
air quality maintenance planning:
1. General Conclusions
a. Land use can be quantified. However, the available techniques
require detailed area-specific data bases.
b. Procedures do exist for the conversion of detailed land use
and activity data to pollutant emissions. However, the pro-
cedures are specific to the study area for which they have been
generated and the results imply that these procedures would need
to be developed on an area-specific basis.
c. Data allocation procedures do not exist for disaggregating
pollutant emissions data. However, the disaggregation of
projected (long-term) pollutant emissions is dependent upon
detailed land use and activity data that may not be available.
d. Several procedures exist to relate land use and/or transportation
data to air quality. However, they are specific to the area
for which they have been developed and would require considerable
effort to develop the required data bases in other areas.
B-3
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e. No generally applicable procedure currently exists for pro-
jecting the long-term air quality impact of land use within
the level of detail and accuracy required for the preparation
of air quality maintenance plans.
2. Emissions Calculations
a. Techniques are available to calculate emissions given detailed
process data for each source.
b. Techniques are not readily available or generally applicable for
converting land use or activity data directly to the process
data necessary for emissions calculations.
3. Emissions Projections
a. Short-term (1 to 5 years) emissions projections techniques
assume little or no change in past trends. Application of
any of these techniques requires careful consideration of the
assumption and generalities used to simplify the techniques
in order to interpret the results.
b. Long-term emissions projection techniques are available for
projecting regionwide emission totals, given a detailed existing
emissions inventory and reasonable regional growth factors.
However, existing long-term growth factors are not accurate in-
dicators of the change in emissions and should only be used as
"indicators" of a possible problem.
c. Long-term projection techniques for traffic and transportation
network data are available that given the geographic detail
necessary to show significant carbon monoxide problem areas within
an AQMA due to these mobile sources. However, these techniques
are very costly to implement and require detailed data base
development that may include land use and activity projections
(Land Use and activity projection models are referenced in
Appendix C).
d. Long-term emissions projection for small area (sub-county)
for stationary sources (other than power plants) is dependent
upon detailed knowledge of the future location of specific
sources. These specific data are not currently available.
B-4
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Assumptions can be made to estimate the probable location
of future stationary sources within the AQMA; however, emissions
projections based on these assumptions would not be sufficiently
accurate to make subarea planning decisions without careful
surveillance and evaluation of these assumptions as new in-
formation becomes available. These emissions projections could
be used to indicate possible or "most probable" problem
areas.
4. Air Quality Diffusion Models
a. Diffusion models are currently available to project carbon
monoxide (CO), total suspended particulates (TSP) and sulfur
dioxide (S02) for any geographic levels of detail for which
emissions data are available. The accuracy of these projections
is dependent upon (1) the accuracy of the emissions data, ambient
air quality, and meteorological data used to calibrate and
validate the given model and (2) the degree to which the area
topographic and meteorological characteristics fit the model
assumptions.
b. Diffusion models are not currently available to represent
the air quality concentrations of any of the secondary
pollutants such as reactive hydrocarbons (HC), nitrogen
oxides (NO ) and oxidants (0 ).
x x
The state-of-the-art in emissions projections and air quality
projections are summarized in Tables 2 and 3ป respectively. It is noted
that microscale emissions and air quality projection techniques are dependent
on the ability to project growth at that level of detail.
B-5
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TABLE 2
STATE-OF-THE ART SUMMARY
EMISSIONS PROJECTIONS TECHNIQUES
Level of Detail or Geographic Scale
AQMA
Microscale Subarea (or regional)
lutant-Source
N
s
L
N
s
L
N
s
L
CO-Mobile
X
X
?
X
X
X
X
X
X
CO-Stationary
X
X
?
X
X
7
X
X
X
HC-Mobile
X
X
?
X
X
X
X
X
X
HC-Stationary
X
7
0
X
X
7
X
X
X
NO -Mobile
x
X
X
?
X
X
7
X
X
X
NOx~Stationary
X
7
0
X
X
7
X
X
X
TSP-A11
X
7
0
X
X
?
X
X
X
so2-aii
X
7
0
X
X
?
X
X
X
NNow (1975)
SShort term (to 1980)
L--Long term (to 1995 or beyond)
o--Not available
?dependent on detailed
data base projection
xcurrently available
B-6
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TABLE 3
STATE-OF-THE ART SUMMARY
AIR QUALITY PROJECTION TECHNIQUES
Level of Detail or Geographic Scale
AQMA
Microscale Subarea (or regional)
Pollutant
N
s
L
N
S
L
N
S
L
CO
X3
X3
X3
X2
X2
?
X2
X2
X2
HC
0
0
0
0
0
0
X1
X1
X1
NO
0
0
0
0
0
0
X1
X1
X1
X
0
X
0
0
0
0
0
0
X1
X1
X1
TSP
X
X
?
X
X
?
X
X
X
SO
X
X
?
X
X
?
X
X
X
Proportional models, i.e., roll back or roll forward
2Subarea and microscale models--6aussian models, statistical models,
climatological models, etc.
3Microscale COLine source models, etc., dependent on traffic assign-
ment projection data.
NNow (1975)
S--Short term (to 1980)
LLong term (to 1995 or beyond)
0--Not now available
?Dependent on data base availabil
XCurrently available
B-7
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APPENDIX C
REVIEW OF SELECTED STUDIES RELATING
LAND USE AND TRANSPORTATION TO AIR QUALITY
-------
I. THE HACKENSACK MEADOWLANDS AIR POLLUTION STUDY ENVIRONMENTAL
RESEARCH AND TECHNOLOGY, OCTOBER 1973.
A. Study Purpose and Scope
The purpose of this study was to (1) develop a general methodology
for considering air pollution in the formulation and evaluation of
alternative urban plans; and (2) to apply this methodology to the planning
alternatives developed for the New Jersey Hackensack Meadowlands District.
In addition, a planning guidelines document was produced to enable urban
planners to introduce air pollution considerations into the planning
process.
B. Analytic Techniques
The Air Quality for Urban Industrial Planning (AQUIP) System developed
and applied in this study consists of a set of submodels or routines
that perform the following:
Preparation of input data descriptive of land use or trans-
portation plan
Conversion of these data into pollutant emissions data.
Prediction and display of mean ambient pollutant concentra-
tions within the area of interest.
ง Evaluation and ranking of the plan with respect to other plans
through analysis of air quality contours and the computation
of quantitative measures of impact.
Utilizing these submodels and techniques, the following can be
evaluated:
The compliance with ambient air quality standards
The impact of regional air quality leyels
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The degree of impact in specific receptors or land use cate-
gories that are especially sensitive to the effects of pollutants
An indication of ways to modify the plan(s) to improve air
quality
LATRAN is the submodel which processes the land-use and transpor-
tation data. The data are independent of grid size and land use is
allocated by geographic coordinates and land use zones. Activities are
designated as point source, line source, or area source generators for
input to the dispersion model. Land use activity and intensity data are
converted to emissions using a set of conversion factors, emission
factors, and activity parameters based on data specific to the Hacken-
sack plan. A set of default parameters was also developed (specific to
Hackensack data) for use when data is missing or incomplete. The air
quality dispersion model used (MARTIK) to convert these emissions to air
quality is a modification of Martin and Tikvart as used in the Air
Quality Display Model (AQDM). The modifications were made to improve
accuracy and to treat line sources directly. Approximation techniques
were used to save computer time. The SYMAP software was used to display
the model output. This displays concentrations as intensity shadings
across the area of interest.
The air quality impact subroutine then performs the following
comparisons on a pollutant-specific basis based on the output from
MARTIK:
Compare maximum concentrations to ambient air quality stan-
dards (AAQS).
Determine percentage influence of background concentration of
total air quality within each plan.
Determine the "average" regional air quality.
Determine the "average" exposure of critical receptors and
land use categories to pollutant concentrations for the aver-
age or worst meteorological conditions.
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C. Model Application
The sample analysis was performed for the Hackensack Meadowlands
Planning District, a four by eight mile area near the densely developed
lower Manhattan area. Four plan alternatives for 1990 were evaluated
and ranked. The pollutants evaluated were TSP, S02, CO, HC, and NO for
X
annual, summer, and winter averages. The analysis was for regional
impact only (microscale impacts were beyond the scope). The sample
analyses concluded that:
The background concentration contribution for the Hackensack
area was so significant that land use planning on a regional
scale would be ineffective for abatement of regional air
pollution levels.
The analysis of impact of alternatives showed significant
difference among spatial patterns due to:
Percent mix of land use
Relative location of land use activities
Relative intensity of land use activities
The observed spatial differences were especially sensitive to
the percent mix of manufacturing and transportation related
land use.
Percentage open-space did not have a significant impact on
regional air quality.
D. Conclusions and Recommendations
The application results were evaluated and a guidelines document
was prepared that can be "generally applied to the land use and transpor-
tation planning process for the consideration of air pollution" in
ranking alternative plans. The guidelines should be applied to other
planning situations only for consideration of regional scale air quality.
Detailed analysis would require the application of the complete AQUIP
system and the development of the associated detailed data bases.
C-3
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Some general conclusions resulting from the analysis are:
It is important to evaluate and rank plans on the basis of
pollutant concentration rather than emissions because:
Air quality standards are related to concentration levels.
Meteorological conditions are critical in determining
capacity of a region to assimilate local source emissions
(i.e., to determine conditions under which planned land
use developments will exceed or comply with AAQS).
Meteorology is critical in determining levels of back-
ground pollutant concentrations transported into and out
of the planning region.
Regional air quality considerations are good for making broad
estimates of the relative air quality impact of alternative
plans but are totally insufficient for the level of detail
required to form the basis for evaluating subarea planning
alternatives.
Regional scale air pollution considerations are not applicable
to the explanation or solution of microscale problems (i.e.,
CO over short time periods and small distances is more likely
to be determined by localized influence or short-term extremes
in meteorological conditions).
The regional scale air pollution considerations are appropriate
within the planning process to improve regionwide air quality
and reduce exposure to the general population and high risk
groups within the general population to high concentrations.
If total concentrations do not exceed AAQS and if the varia-
tion in total regional impact among plan alternatives is less
than 15 percent, the planner can be neutral in the choice of a
plan with regard to regional air quality considerations.
If background air quality concentrations exceed 60-70 percent
of total regional concentration, land use planning is not an
effective abatement strategy for regional problems.
Plan design factors having a primary influence on regional air
quality concentrations and spatial pattern are:
C-4
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Percent mix of land use (manufacturing and transportation
dominate)
Location of land use
Intensity of land use (clustering)
Local topographic and meteorological conditions have a major
influence on air quality patterns.
The following recommendations for further study were made by ERT
based on the results of the study:
Refinements in emissions data, especially activity indices and
projection indices, are required.
Further development of default parameters is needed.
Further calibration of the air quality model (MARTIK) is
required. Meteorological effects studies are needed for model
validation.
A software interface between AQUIP and the computerized data
base of air pollution agencies is needed.
"Rapid estimation techniques" for evaluation and ranking of
plans need to be refined.
Extend AQUIP to the microscale.
Perform sensitivity analysis and development guidelines for
impact.
ง Air quality needs to be examined in relation to other environ-
mental and planning issues, (i.e., water quality, solid waste,
cost/benefit, etc.).
E. Data Requirements
To complete the entire AQUIP sequence, detailed land use intensity
or activity, emission factors, meteorological and topographic, ambient
air quality, and conversion of default parameters are needed. Accuracy
is greatly reduced as any of these data are missing.
C-5
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F. Model/Calibration
Existing ambient air quality and meteorological data were used to
develop simple ratios of existing to projected data to calibrate the
model. Where meteorological or topographic conditions vary significantly
from the Meadowlands conditions, the model would require extensive
recalibration.
G. Model or Study Status
AQUIP is operational for the Hackensack planning region only and is
currently operational on the ERT computer only.
H. Applicability to Other Areas
Based on the characteristics of the Hackensack land use plans, the
following can be said: (1) some new routines would be required to
reflect the appropriate planning assumptions of new planning develop-
ment. However, the overall AQUIP procedures and subroutines are suffi-
ciently general to be applied wherever data are sufficient to operate
them, (2) the explicit quantitative results are less generally appli-
cable as they are representative of the meteorology and topography of
the Meadowlands. Any variation from these conditions must be considered;
and (3) AQUIP can be used as a projection tool as well as a diagnostic
tool, (i.e., it can be used to evaluate strategies).
II. A REPORT ON GUIDELINES FOR RELATING AIR POLLUTION CONTROL TO lAND USE
AND TRANSPORTATION PLANNING IN THE STATE OF CALIFORNIA
A. Study Purpose and Scopp
The study purpose was to prepare guidelines for integrating the
goal of achieving and maintaining air quality with the land use and
C-6
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transportation planning processes in California metropolitan regions.
The initial idea was to develop guidelines for preparing air pollution
elements in local general plans. However, this idea was dismissed
because of the regional nature of the air pollution problem resulting in
several technical and administrative problems. Instead, a combination
regional/subarea approach to integrating air quality goals into the
planning processes was suggested as a solution.
The process consists of six steps: (1) compiling detailed inven-
tories of air polluting emissions in subareas of air basins, (2) desig-
nating maximum emissions allowable in each subarea, (3) project subarea
emissions likely to be generated by sources indicated in land use and
transportation plans for future years, e.g., 1985 and 1995, (4) evaluate
and revise the plans so that the maximum emission limits are not exceeded,
(5) adopt and implement the plans, and (6) monitor public and private
development through a refined environmental impact assessment process.
The key to the process is the concept of allocating allowable emissions
to subareas within air basins. The premise is that the emission limits
will be set up so that air quality standards will be met if plans and
projects conform to the limits. An appeal process is suggested to allow
deviations in those cases where technical information is available to
ensure that air quality standards will not be violated.
B. Analytic Techniques
1. Land Use Model
At least three sectors of land use would be modelled: manu-
facturing, residential, and commercial.
Land use inventories and projections by planning subarea would
be required.
Useful source variables to be inventoried and projected as far
as possible are: acreage, residential density, employment
density, nature of uses, production levelt fuel consumption,
location with respect to transport facilities, and other
physical or socioeconomic variables, as well as amounts of
emissions.
C-7
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2. Data Allocation or Disaggregation Technique
The analyses proposed for this study are geared to a planning
subarea basis, so data would be allocated or disaggregated by
planning subarea.
No grid with receptor points is specifically mentioned, but
might be used in the monitoring process which is suggested.
Land use would be given in terms of acreage for use with
emission density factors of emissions per acre in stationary
source area source emissions calculations; no specific area
size is mentioned in connection with mobile source area source
emissions calculations.
3. Previous Emissions Inventories
Existing inventories for counties and air basins are too
general for detailed air quality planning; suggests that Basin
Coordinating Councils compile planning subarea emissions
inventories.
Five major pollutants covered in 1970 inventories: organic
gases, particulate matter, oxides of nitrogen, sulfur dioxides,
and carbon monoxide.
Four source groupings used in breakdown of emissions by source
in 1972 inventory: process losses, fuel combustion, waste
disposal by burning, and mobile sources classified by point
and area sources.
4. Emissions Inventory Development -- The study suggests that total
emissions inventory be composed of three separate inventories:
(1) point sources, (2) stationary source area sources, and (3)
mobile source area sources. Point sources are defined as any
stationary source that emits more than 100 tons per year of any
pollutant within an urban place with a population over one million
or more than 25 tons per year in a less populated area (high
emitters). Area sources, all other stationary sources (low emitters),
are aggregated on an area basis; mobile sources, also treated on an
area basis, are aggregated on an area basis.
C-8
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Point Sources:
Point sources emissions inventory information can be obtained
directly from emissions data or indirectly using standard
emissions factor on source parameter data collected by previous
inventories and disaggregated by planning subareas.
Stationary Source Area Sources:
Emission density factors would be developed for various land
use categories.
Development of emission density factors would be based on
nature and intensity of land use data on existing sources;
types of nature and intensity of land use data are: residen-
tial or employment density, nature and level of production,
nature and level of fuel consumption, location with respect to
transport facilities, and other physical and socioeconomic
variables.
The emission density factors would be multiplied by acreage
devoted to each existing land use in a planning subarea to get
detailed stationary source area source emission inventories
for planning subareas.
Mobile Source Area Sources:
Emissions inventories by planning subarea would be derived by
multiplying vehicle-miles traveled information by appropriate
emissions factors.
Emissions factors for transportation systems have been developed
already.
Vehicle-miles traveled information from transportation plans
would be in link format and would have to be aggregated by
planning subarea.
Separate calculations would be needed for the different modes
(auto, bus, train, truck, ship, and aircraft).
Total Inventory:
Total emissions inventory in each planning subarea would be
determined by combining the three inventories.
-------
5. Emissions Model:
Emissions model consists of the methodology used in developing
the inventory.
Future emissions would be projected for 1985 and 1995 based on
current or modified emission or emission density factors and
projections from land use and transportation plans of: (1) either
point source emissions or source parameter data, (2) area
source acreage by land use category, (3) vehicle-miles traveled.
Modifications to emission factors would reflect future techno-
logy, changes in fuel usage, motor vehicle emissions controls,
etc; modifications to emission density factors would reflect
all of the above plus changes in nature and intensity of land
use parameter distributions of future sources.
Modifications of factors and projections would be made as new
data becomes available.
The National Emissions Data System is a computer program to
facilitate emissions calculations for point and area sources;
could be used after emissions inventory information is put
into the necessary format.
6. Air Quality Model:
No sophisticated validated air quality model is presently
available to predict values in California air basins.
The study recommends that the initial program use the pro-
portional model with provisions for deviation from the model
where technical information is available to ensure that ambient
air quality standards not be exceeded by the proposed deviation;
recommends usage of a more refined model for the continual
program, if and when such a model (or models) is developed,
calibrated, and validated for individual California air basins.
The basic relationship of the proportional model is:
Maximum Concentration
of pollutant m base year
in air basin
Air quality standard m
E allowable in air basin
E base year in air basin
m
m
C-10
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where:
Em is the emissions of pollutant m; the output item is the Em
allowable in the air basin.
ง The air quality modeling assumption implicit in the proportional
model is that the worst ambient air quality concentrations in
the air basin are roughly proportional to the total amount of
emissions in the basin.
7. Air Quality Impact Model:
The control method proposed is a proportional rollback of this
form:
Em in planning subarea Em allowable
in 1970 = in planning subarea
Em in air basin in 1970 Em allowable in air basin
where:
Em is the emissions of pollutant m; the output item is the
Em's allowable in planning subareas.
The air quality impact modeling assumption implicit in the
control method is that reducing emissions by a constant pro-
portion in all planning subareas will result in roughly that
proportion improvement in air quality to the region in general
and to the worst concentrations in particular.
C. Application
The applications would be to the air basins of the State of Cali-
fornia.
D. Study Recommendations/Conclusions
The study recommends a regional/subarea approach to integrating air
quality goals into land use and transportation plans, rather than the
development of separate air pollution elements to local general plans
and regional transportation plans.
The study also recommends using the proportional model for modeling
air quality and rollback as a control method, with provisions for allowing
C-ll
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deviations from emissions limits where an adequate case can be made for
the deviation not interfering with attainment or maintenance of air
quality standards.
The study recommends separating stationary sources into high emitters
and low emitters and treating the former as point sources, using point
source emission factors, and the latter as area sources, using emission
density factors. Mobile sources are treated as area sources, but emissions
are based on emissions/VMT factors.
The study recommends using more refined models as they are cali-
brated and validated for California. Periodic updating of emission and
emission density factors is also recommended.
E. Data Requirements
Land use plan parameters: covered under "Land Use Model" transpor-
tation plan parameters: vehicle-miles traveled, possibly speed and
other traffic flow characteristics emission factors: point source emission
factors based on process weight, energy consumption, etc. (available);
emission density factors for low emitter stationary source area sources
(need to be developed); emission factors per vehicle-mile traveled and
possibly speed, by mode (available or soon to be available).
F. Validation or Calibration
The proportional model has so far proven to be as reliable as would
be derived from a more complicated method. However, more refined models
calibrated or validated for individual air basins in California would be
desirable. Currently research is underway to develop such models in the
San Francisco Bay Area, in the South Coast Air Basin, and in San Diego.
G. Model or Study Status
The study presents a set of recommended guidelines, application
results have not been published.
H. Applicability to Other Areas
The guidelines recommended are applicable to any area.
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III. THE TRANSPORTATION AND AIR SHED SIMULATION MODEL (TASSIM) REPORTS,
DOT-OS-30099-3 AND D0T-0S-30099-4, MARCH 1974
A. Study Purpose and Scope
The purpose of this study was to develop a model that integrates
existing urban transportation models, vehicle emission factors, and a
simple air diffusion model to analyze the air quality effects of various
transportation policies. The model was calibrated and applied for the
Boston area, disaggregated into 122 subareas to simulate the air quality
effects of various transportation controls, land use controls, and
stationary source policies. The model structure and several model
applications are described.
B. Analytic Technique
The TASSIM computer technique is composed of three separate programs,
each of which have two or more sub-programs.
1. TASAQD Program The TASAQD program is a simplified version of the
Air Quantity Display Model (AQDM) which models air pollutant concentra-
tions in each subarea resulting from individual large point sources.
The basic simplification is the substitution of a single typical stability
class.
2. TASSIM Program The TASSIM program contains the following seven
sub-programs.
TR6EN - Forecasts total person trips made to and from each
sub-zone. This submodel uses the trip generation equations
and zonal land activity data typical to most urban trans-
portation studies.
TRIPAL - Uses the zonal productions and attractions developed
by TRGEN and performs trip distribution, mode split and net-
work assignment to a composite highway and transit district or
"spider" network.
C-13
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EMIT - Calculates auto emissions based on the network assign-
ments and speeds and combines them with non-mobile area emissions
to produce air quality surfaces for the region and determines
the frequency with which the Federal standards are exceeded in
each of the subareas. The diffusion model used for mobile
and area sources in this subprogram is a Gaussian vertical
distribution (Honna-Gifford model).
t MODSPT - Adopts the mode split models developed in the urban
transportation study to the district level composite highway
and transit network to produce estimates of transit person and
auto trips for various pricing, level of service, and control
policies.
TRPDST - Adopts the gravity model for person trip zonal distri-
bution to the district level network.
SKIMT and JAY - Calculates the interdistrict impedance using
a modificaton of the "Moore" minimum path model. Highway only
and combined highway-transit network interdistrict impedances
are calculated and used as input to the mode split model.
DIAL and DIALT - Assign transit trips to the transit subnet
and uses a version of the parallel probabilistic assignment
algorithm to assign auto person trips to the composite auto-
transit network.
3. TASMAP Program -- The TASMAP program generates maps portraying the
geographical concentrations or concentration changes using the data
developed by the diffusion models.
C. Application
The models described above were calibrated for the Boston regional
area and applied to test the effect on air quality by:
Reducing vehicular emissions
t Applying various prohibition and licensing schemes to auto
trips
t Increasing auto occupancy
Reduction of transit fare
C-14
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Performance improvements of highway and/or transit systems
t Controlling urban development patterns
Reducing stationary source emissions
The regional and subarea air quality for 122 subregions were
evaluated for the total pollutants, TSP, S02, CO, HC, and NO, and the
change in these pollutants with the various policies and system changes
listed above.
D. Study Recommendations and Conclusions
The application for the Boston area permitted an analysis of a wide
variety of factors that would affect the air quality. The TASSIM model
contains submodels for trip generation, trip distribution mode split,
assignment, composite highway and transit network representation, point
source emissions, area source emissions and mobile source emissions, as
well as a diffusion model. It also provides for analysis at the sub-
area level as well as the regional level. Because the model chain
contains all submodels which are executed very economically in sequence,
the effect of policy decisions on the entire model chain can be analyzed
for a large number of policy considerations at the subregion as well as
the regional level.
Some general conclusions resulting from the analysis were:
t It is very important to consider the total effect of localized
air quality control policies since an improvement of air
quality may occur in one subarea but may be reduced in other
subareas.
Reducing vehicle emissions to the level set forth in the 1970
Clean Air Act is an extremely effective technique for improving
air quality in the metropolitan area.
t The spatial distributions of emissions, and not just the
metropolitan-wide aggregate of emissions, must be considered
in order to effectively evaluate the effects of individual
policies or combinations of various policies.
C-15
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It is very difficult to generalize about the effectiveness of
point source controls because the relationship between point
source and concentrations vary widely due to the local meteoro-
logy, topography, and the location of large point sources.
An evaluation of the cost and effectiveness of various policies
indicate some of the control strategies analyzed produced
small improvements in air quality at relatively large cost.
E. Data Requirements
To apply the TASSIM model requires:
Subarea, interarea travel times and trip interchange
Inventories of stationary emissions
Meteorological parameters
Vehicle emission rates
Social-economic characteristics of the population for the
calibration and application of the trip generation and mode
split equations
Person trip generation equations (usually developed as part of
the transportation planning process)
A "Gravity Model" trip distribution procedure. ("F" and "K"
factors developed as part of many of the transportation planning
process)
t A "Mode Split Model" to be applied to person trips distributed
by the gravity model
F. Calibration
The models for trip generation, trip distribution, and mode split
developed as part of the transportation planning process, were used with
1970 census land activity data and employment data, and the forecasted
air quality compared favorably to the monitoring data collected in the
area. If the trip generation, trip distribution, mode split models,
interarea travel times, trip interchange, and inventory of stationary
sources are available, the model could be calibrated for other metropoli-
tan areas.
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G. Model or Study Status
The TASSIM model is operational, and FORTRAN decks of the programs
have been executed on an IBM 370/145 and 370/165.
H. Applicability to Other Areas
The TASSIM model is designed to use data and models developed by
many of the urban transportation studies. If person-trip generation
equations, gravity type distribution models, and post-distribution mode
split models are available, the TASSIM model could be calibrated and
applied. In some cases substantial modification would be required to
the TASSIM model to accommodate the models generated by the transpor-
tation study. The model would be applied at a 100 to 200 subregion
area level. These subregions would probably be combinations of the 600 i
to 1000 transportation planning zones to facilitate the model calibration
data developed in the transportation study at the zone level.
The model uses a district level spider network in which all highway
and transit facilities are represented by direct connection between
district centroids. These "links" are encoded with average characteris-
tics of all the transportation facilities they represent. For the
mobile source emissions, the number of vehicles assigned to the link
and the adjusted speed assigned to the link are used to calculate the
emission of all facilities represented by this link. They are prorated
to the two subareas connected by the link based on the square root of
the area of the subregions. With this technique it is difficult to
identify the unique characteristics of specific facilities and the
effect traffic volume would have on the operating speeds of individual
routes.
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IV. AIR POLLUTION/LAND USE PLANNING PROJECT, PHASE II, FINAL REPORT,
VOLUME II, ARGONNE NATIONAL LABORATORY, CENTER FOR ENVIRONMENTAL STUDIES,
MAY 1973.
A. Study Purpose and Scope
The general purpose of the project was to examine relationships
between air quality and land use guidance and control practices. The
specific objective of the work was to investigate the utility of various
land use parameters in describing the air quality impacts of land use
plans. The Chicago metropolitan region was used as the test region.
B. Analytic Techniques
The methodology envisioned for predicting the air quality impacts
of land use plans from various land use parameters, a part of which is
investigated involved:
A land use model to forecast growth or change in land use
based on rates of change in land use, employment, and pro-
ductivity for the different kinds of manufacturing land uses,
changes in housing stock and population for residential land
use, and changes in square footage of floor space for commer-
cial land use.
An emissions model based on either emission density factors
(emissions per acre) or other emission factors to relate
emissions to land uses.
An air quality model to determine air quality levels in the
region, assuming knowledge of quantity of emissions. The air
quality model used was the Air Quality Display Model.
The work described examined the feasibility of developing useful
emission factors for an emissions model. Only one pollutant was exa-
mined as a test case-particulates.
Separate analyses were conducted for manufacturing land use and for
residential/commercial land use.
For manufacturing land use, two methods of developing emission
factors were tried. The first method was to develop emission density
C-18
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factors. Four sets of emission density factors, based on mean, median,
and "best fit" representations of source inventory data were tried. The
usefulness of each set of emission density factors was determined by
seeing how well the air quality representation obtained using the factors
compared to the air quality representation obtained using the point
source emissions data.
The second method was to test the feasibility of using some com-
bination of the following parameters-number of employees, process weight,
fuel consumption as well as acres of land-to forecast emissions of
manufacturing activities. Linear regression was used as a method of
analysis. Statistical tests such as correlation coefficients were used
to judge usefulness of parameters for prediction.
For residential/commerical land use, the observation was made that
for the test pollutant, particulates, that emissions were a direct
function of fuel consumption and therefore, that it was sufficient to be
able to predict fuel consumption. The land use parameter used for
prediction of residential fuel consumption was mean energy use per
dwelling unit, by dwelling unit category. The land use parameter used
for prediction of commercial fuel consumption was mean energy use per
thousand square feet by commercial size category. Analysis of variance
was used to determine the breakdowns of dwelling unit categories and of
commercial size categories that were significant.
C. Application
The test analyses were performed on data from the Chicago Metropoli-
tan Air Quality Control Region. The primary data sources used were
emission inventories collected by the City of Chicago and the State of
Illinois Environmental Protection Agency and land use data on a square-
mile basis collected by the Northeastern Illinois Planning Commission.
D. Conclusions
None of the four sets of emission density factors tested
predicted air quality deterioration from manufacturing land
use sufficiently well. Thus, the emission density concept was
rejected.
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One of the linear regression models tried to predict manu-
facturing emissions on the basis of number of employees and
acres of land. As these two parameters are easier to predict
or more likely to be predicted in most land use planning than
the other two parameters being examined, the model was an
effort to determine if they were sufficient to predict manu-
facturing emissions. They were not. The linear regression
model based on all four parameters, however, was sufficent.
An attempt was also made to see if number of employees and
acres of land could be used to determine the other two para-
meters, process weight and fuel consumption. If the latter
two could be determined from the former two, input would then
be available for prediction of emissions from the four para-
meter model. However, the results were inconclusive.
For prediction of residential emissions, the breakdown of
dwelling unit categories that was determined significant was
between light residential (less than or equal to twenty dwelling
units per building) and heavy residential (more than twenty
dwelling units per building). For prediction of commercial
emissions, the breakdown of commercial size categories that
was determined significant was between light commercial (less
than or equal to 20,000 square feet per building) and heavy
commercial (more than 50,000 square feet per building). Mean
energy use per dwelling unit or per thousand square feet were
determined for each category and were found useful predictors
of emissions.
E.,F.,G.Data Requirements, Model Calibration, Model or Study Status
The Argonne project terminated before a methodology or model for
predicting air quality impacts of land use plans from land use parameters
was developed.
H. Applicability to Other Areas
The approach taken by the project is applicable to other areas.
However, the specific research results for the emission model cannot be
assumed applicable to other areas, as they reflect data specific to the
Chicago region.
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V. BALTIMORE REGIONAL ENVIRONMENTAL IMPACT STUDY (BREIS) ALAN M.
VOORHEES AND ASSOCIATES, INC., MARCH 1974.
A. Study Purpose and Scope
The purpose of BREIS was to evaluate the regional environmental
impacts of alternative land use and transportation policies in the
Baltimore region. Several environmental analysesair, noise, water,
solid waste, socioeconomic, and trafficwere performed for a 1970
base year plus three 1980 alternatives and four 1995 alternatives for
the highway system.
B. Analytic Techniques
The Urban Systems (USM) land use model was first used to determine
regional development data for each of the alternatives. Next, a series
of transportation models were used to determine trip generation, modal
split, and traffic assignments for each alternative.
An emissions model was developed to calculate motor vehicle emis-
sions by link and by trip ends (for cold start and hot soak emissions)
from the output of the transportation models. Emissions of CO, HC, and
NO were summed to the regional planning district level and further
x
summarized by county and for the entire study area. Comparison of
emissions from different alternatives indicated the effect of the highway
system on automotive emissions and the trend in emissions over time
(1970, 1980, and 1995).
Emission data for stationary sources and non-automotive mobile sources
were obtained from available inventories. These were projected by a two-
step procedure. First, controls that would be applied to individual
point sources in the future and to area source categories were esti-
mated. Then, the controlled emissions were increased by use of appro-
priate growth factors from the Urban Systems model data or U.S. Depart-
ment of Comerce projections to account for growth. The two partial
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inventories were combined to show the differences in total emissions by
alternative and the contribution of motor vehicle emissions in each case.
C. Model Application
For pollutants other than CO, maximum projected concentrations were
simply estimated by proportional reduction with the emissions data. For
carbon monoxide, the APRAC-1A urban diffusion model was used to determine
maximum CO concentrations for each alternative. Areas of high suspected
concentrations were found by using the grid-point version of that model.
Then, receptor points were specified in the areas indicated by the grid-
point version to have high background levels, and the synoptic version
with the street-canyon subroutine was used to estimate maximum 1-hour and
8-hour concentrations alongside the major streets in those areas.
D. Conclusions and Recommendations
The results of this study have been used by Federal agencies to
assess the regional impact of alternative land use and transportation
policies. Because the traffic data was prepared at link level it has
been possible to perform minor level CO analysis as well for assessment
of highways at the project level. Further applications will be completed
for the efforts of transportation control strategies and energy consump-
tion. The local decisionmakers are utilizing the results to further
evaluate alternative policies.
E. Data Requirements
The procedure applied in Baltimore served to update the 3-C trans-
portation plan as well as to provide a regional environmental assessment.
Thus, the activity allocation model and the travel simulation models
required input data at the zonal level (approximately equal to 2-5 square
miles) as part of the overall process. The air quality and other environ-
mental assessments were conducted at a more aggregate level.
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F. Model Calibration
The land use and transportation models were calibrated according to
standard practice. The CO model was calibrated on limited receptor
sites.
G. Model or Study Status
The BREIS study is essentially complete; however, ongoing analysis
will further refine the data and the procedures.
H. Applicability to Other Areas
The approach is readily applicable to those areas that have a
quantified land use model and/or a comprehensive update of the trans-
portation modeling process. It can be used to evaluate alternative plans
as well as incremental plan changes.
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APPENDIX D
AIR QUALITY MODELS
-------
AIR QUALITY MODELS
The following is a brief summary of the current state-of-the-art
models that might be utilized. These can be broadly categorized as
Emission Models and Dispersion Models.
1. EMISSION MODELS
Emissions models are usually simple in form. Their product often
takes the form of emissions maps of the community which show pollutants,
in terms of tons per day, discharged on a subarea basis. By this means,
areas overburdened by pollution can be identified for purposes of abate-
ment and avoidance of adding to an existing problem by appropriate
planning and zoning measures.
Emissions modeling usually begins by surveying the various sources
of air pollution within each subarea including stationary, mobile,
refuse, and industrial combustion or evaporation loss sources. The
volume of daily fuel burned or chemicals subject to evaporation processes
is obtained. Research-produced emission factors are used which correlate
the amount of pollutants produced per unit of fuel or chemical; they are
multiplied times the above volumes to obtain the daily contaminant
production. Pollutant tonnages from all sources are cumulated to dis-
cover the total weight of each pollutant being produced in the subarea.
The final result is usually expressed in tons per square mile.
2. DISPERSION MODELS
Four major groupings of dispersion models are currently in use. The
first type is a statistical model in which air pollution levels are corre-
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lated with an emission inventory and meteorological data for a given region.
This type of model may be used for pollution-episode forecasting provided
that there is ample data.
A second type is the "box model" in which the pollutants in a
volume of air enclosed by a given area on the ground are assumed to be
uniformly mixed. The concentration of pollutants within this box are
then given by the rates of emissions at the ground area and transported
by horizontal wind through the box. Transport by wind out of the box is
air at the pollution concentration in the box. Transport by wind into
the box is air at the pollution concentration of the neighboring box just
upwind. This model has been used with some success for pollution pre-
dictions given a suitable emission inventory. Depending on resolution
requirements, a region may be divided into several such boxes. Major
problems are the assumption of uniform mixing with the box and the usual
lack of knowledge of the altitude of the temperature inversion, if any.
The third, and currently the most popular, grouping is the Gaussian
plume type. These models give the pollutant concentration as a normal
Gaussian distribution in directions crosswise to the wind. The standard
deviation for these distributions is provided as a function of travel
time or distance from the source and the current meteorological condi-
tions (especially wind speed, terrain roughness and the strength of
incident solar radiation). Such distributions have been developed for
point, line, and area sources (see especially the work of Pasquill,
Gifford, and Turner). Such models are widely used for simple pollution
calculations for single sources. More recently, a large number of
workers has developed sophisticated computer programs for integrating the
pollution concentration of the plumes from many such sources (as might
comprise a region or city) to obtain the total pollution level at a
single location or a set of isopleths. A major drawback of this model is
that it is valid only for a relatively short period during which both the
D-2
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wind speed and meteorological conditions remain constant. Moreover, the
model becomes invalid at zero or low wind velocities (in which one such
model resorts to the box model).
The fourth grouping of models may be termed "analytical." In such
models, an attempt is made to solve the fundamental equations governing
air flow diffusion of pollutants. The preceding two groupings of models
presuppose a single solution to these equations and hence are limited
inherently in their range of applicability and accuracy. Moreover, the
use of an analytical model is less dependent on the availability of
detailed meteorological data (e.g., wind fields). Information on terrain
features is required instead.
Another major advantage of the analytical type of model is that
chemical changes to the emitted pollutants can be introduced in a natural
way. (This cannot be done in a Gaussian plume model). Thus the forma-
tion of photochemical oxidants can be modeled. Unfortunately, models of
the chemistry of the formation of photochemical oxidants are still in the
research stage. Such models developed to date have been used only with
partial success.
The following Evaluation of Some Climatological Dispersion Models is
extracted from the User's Guide for the Climatological Dispersion
Model, EPA-R4-73-024, December 1973. This evaluation provides an excel-
lent review of dispersion models available for evaluation of TSP, and SO2
air quality.
Simple models to estimate carbon monoxide air quality were des-
cribed in the Guideline for Designation of AQMAs. More sophisticated
approaches include the EPA-ARAC (a model which incorporates the Stanford
Research Institute Model for CO, and Gifford-Hanna Models. These models,
incorporated in three of the studies summarized in Appendix B, are:
t The Hackensack Meadowlands Study - used Gifford-Hanna (modified)
The BREIS study used SRI model (HPRAC 1A)
D-3
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TASSIM used a modified Gifford-Hanna approach
Models to project ambient concentrations of reactive hydrocarbons,
NO^, and photochemical oxidant are in the development stages and are not
currently available or generally applicable.
D-4
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AN EVALUATION OF SOME CLIMATOLOGICAL DISPERSION MODELS
by
D. Bruce Turner*, John R. Zitrimerman*, and Adrian D. Busse*
ABSTRACT
Six different dispfersion models were used in a climatological
mode of application with point source and area emission data to
calculate annual (1969) sulfur dioxide and total suspended particulate
matter for the New York Air Quality Control Region. Two of the models,
the Air Quality Display Model and the Climatological Dispersion Model,
use joint frequency distributions of wind direction, wind speed, and
stability class as meteorological data. The Climatological Dispersion
Model (single stability} requires only a wind direction frequency and
harmonic mean speed for each direction. The other three models: Gifford
"72, Modified Hanna, and Modified Hanna Including Source Height; require
only mean annual wind speeds for climatological application.
Simple models are as highly correlated with measurements as are
the more complex models, explaining 70% of the sulfur dioxide variance
and 40ฃ of the particulate variance. For S02, root mean square errors
for the best complex model are 52; those for the simple models are 56
to 59. The standard deviation of the measurements is 72. For particulates,
root mean square errors for the complex model are 16; those for the
simple models are 19 to 40. The standard deviation of the measurements
1s 23.
It is difficult to achieve results surpassing those of the simple
models. Of the two more complex models, the AQDM and the CDM, the CDM
yields smaller errors with means and maxima nearer those of the measurements.
Evaluation of models should include comparison of results with those
from simple models applied to the same data.
*0n Assignment from the National Oceanic and Atmospheric Administration,
Department of Commerce
D-5
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INTRODUCTION
Six different dispersion models were used to calculate annual
(1969) sulfur dioxide and total suspended particulate matter for the
New York Air Quality Control Region. Two of the models, the Air Quality
Display Model and the CIimatological Dispersion Model, use joint frequency
distributions of wind direction, wind speed, and stability, as
meteorological data. The CIimatological Dispersion Model applied for
a single stability requires only a wind direction frequency and harmonic
mean speed for each direction. The other three models based upon ideas
of Gifford and Hanna (1971, 1972) require only mean annual wind speeds
for climatological application. These are referred to as: Gifford '72,
Modified Hanna, and Modified Hanna Including Source Height.
The emission inventory, measured air quality data, meteorological
data, and climatological estimates of pollution concentration using the
Air Quality Display Model were obtained from EPA's Air Quality Manage-
ment Branch. Emission estimates for 1969 for both pollutants for 854
2 2
area sources varying in size from 1 km to 100 km , and for 674 point
sources were included. Estimates of stack height, stack diameter,
stack gas exit velocity, and stack gas temperature were also included
for the point sources. A stability wind rose (joint frequency distribution
of wind direction, wind speed, and stability class) was available for
La Guardia Airport based on the 3-hourly observations during 1969. These
observations are routinely available in computer compatible form (punch
cards or magnetic tape).
D-6
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Each of the models was used to calculate mean annual concentrations
of sulfur dioxide at 75 locations and total suspended particulate matter
at 113 locations. These estimates were compared with mean annual
ป
concentrations based upon measurements.
DESCRIPTION OF MODELS
1. Air Quality Display Model (AQDM)
The AQDM, a climatological model based on ideas of Martin and Tikvart
(TRW Systems Group, 1969; Martin and Tikvart, 1968; and Martin, 1971),
considers the joint frequency distribution of wind direction to 16
points, wind speed in 6 classes, and stability categories in 5 classes.
Computations for a receptor point are made by considering the contribution
of each point and area source to this receptor. Separate calculations
are made for each speed class - stability class combination for the
wind direction sector about the receptor that contains the source.
For area sources a modification of the virtual point source method is
used. Estimation of area source heights are assumed to be effective
height of the area source. The effective height can be different for
each area source. Holland's plume rise equation (Holland, 1953) is
used to estimate the effective height of point sources. A feature
of the AQDM is that a source contribution file consisting of the
partial concentration of each receptor due to each point and area
source 1s retained at the end of the computation. This is primarily
used as Input to control strategy studies.
D-7
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2. Climatological Dispersion Model (CDM)
The CDM described in detail by K. L. Calder (1971) has been applied
to air quality estimates for Ankara, Turkey, and St. Louis (Zimmerman,
1971, 1972) for the Committee on Challenges of Modern Society. Although
similar in many respects to the AQDM, the CDM contains several distinct
features. In the CDM, area sources are calculated using the narrow
plume hypothesis (Gifford and Hanna, 1971) applied for winds within a
sector (Calder, 1971) which involves an upwind integration over the
area sources. Emission rates at various upwind distances, using an
expanding scale, are averaged over an arc within the sector. A power
law for the vertical wind profile which is a function of stability is
used to extrapolate surface winds to the source height. Estimation
of effective height of point sources is by Briggs plume rise (Briggs,
1969). The total concentration at each receptor is the sum of 32
concentrations. These concentrations are those from point and from
area sources for each of the 16 wind directions. These values are
retained and are useful in plotting direction contribution pollution
roses. The running time of the CDM is about 73% of that required by
the AQDM.
3. Climatological Dispersion Model (Single Stability)
Whereas both the AQDM and the CDM are applied for 5 different
stabilities and 6 wind speed classes within each stability class,
this model performs the calculations for a single stability and further
D-8
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reduces the computations by using a single wind speed for each of
the 16 wind direction sectors. The single wind speed is a harmonic
mean of the average speed for each wind speed class weighted for its
frequency. The running, time of this single stability version of the
CDM is about 30% of that required by the CDM.
4. Gifford '72
Drs. Frank Gifford and Steve Hanna of NOAA's Atmospheric Turbulence
and Diffusion Laboratory in Oak Ridge, Tennessee, have been active
in developing simple dispersion models for estimating concentrations
(Gifford and Hanna, 1971; Hanna, 1971). In a recent manuscript
(Gifford and Hanna, 1972), they have suggested use of
VC.4- (')
u
where xA is the concentration in ygm"3 of the pollutant of interest
due to all area sources for a particular averaging time, C is a
dimenslonless constant, q 1s an average area emission rate In ygm^sec'1
In the vicinity of the receptor, and u 1s the mean wind speed in m sec"1.
Both q and u are for the same averaging time as the concentration, xA<
They suggest that the values of C are 50 for sulfur dioxide and 225
for particulate matter. Concentrations at this receptor from point
sources for the same averaging time should be added to the concentrations
D-9
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from area sources. These can be determined from an appropriate point
source model. Without firm direction from the manuscript of Gifford
and Hanna as to what area about the receptor should be used to obtain
average area emissions, the authors selected an area after an investi-
gation which will be described later.
5. and 6. Modified Hanna
Since emissions close to a receptor at about the same height as
the receptor have a greater influence than emissions at greater distances,
it was felt that an improvement to the above Gifford '72 model could
be made which would eliminate the use of the rather arbitrary constant
C, and would also eliminate the difficulty of not knowing just which
area should be considered in determination of the average area emission
rate. The model can be expressed as:
XA " "4" J ki ^ + b (2)
where i is an index referring to a range of distances from the receptor,
q. is the average area emission rate for this range.of distance about
the receptor, u is mean wind speed as before, b is background concentration
of the pollutant considered beyond the last distance considered in the
summation, and the coefficient, k, is determined from:
D-10
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th
where x-j and x^ are the lower and upper limits of distance of the i
range, az is a dispersion parameter dependent upon distance and
representative of mean stability conditions for the period of interest,
H is a single effective height of emission for the pollutant considered
area sources in the region under consideration. In general, the
value of b will be the concentration of the particular pollutant at
the boundaries of the region considered, i.e., the boundary of the
emission inventory. Note that the k's are dependent only upon the
mean meteorological conditions and the height of emission and, therefore
will be constant for a given distance range, and independent of receptor
location. On the other hand, thelT" 's are determined for different
distance ranges about each receptor and, therefore, are dependent
upon receptor 1 oration.
Model 5, referred to as the Modified Hanna, is applied with H=0.
This is the same in concept as that of Steve Hanna (1971). The only
difference is that 1n this model sources are considered for ranges of
distance without regard to direction variations. For this model the
values of k can be determined analytically.
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Model 6, referred to as the Modified Hanna Including Source Height,
uses a mean value of effective height of emission for each pollutant.
For this case the values of k are determined by numerical integration.
Both Models 5 and 6 can be considered as further simplifications
to the CDM and CDM (single stability) models since another liberty
has been taken, that of calculating emissions for various distance
ranges instead of in each wind direction sector.
APPLICATION OF THE MODELS TO THE NEW YORK REGION
With each of the models, calculations of ground level concentrations
of both sulfur dioxide and total suspended particulate matter were made.
Measurements of sulfur dioxide were available at 75 locations and of
particulate matter at 113 locations.
As indicated, the AQDM was applied to the data for this area by
_3
the Air Quality Management Branch. A background of 35 ygm was added
to each calculated value of particulate concentration before comparing
with measurements. A background of 35 was also added to each calculated
value of particulate matter by the CDM before comparina with the
measurements.
For applying the CDM for a single stability, Table 1 lists the
frequencies and the harmonic mean wind speeds for each direction. The
model was applied for three different single stabilities. The values
used for the cz parameter most closely approximate those corresponding
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TABLE 1
Frequencies and Harmonic Mean Wind Speeds for Each Direction
SECTOR
f(e)
u (e)
(m sec"^)
NNE
NE
ENE
E
ESE
SE
SSE
S
SSW'
sw
wsw
w
WNU
NW
NNW
N
0.088
0.054
0.076
0.084
0.036
0.010
0.014
0.025
0.117
0.044
0.062
0.075
0.071
0.086
0.082
0.075
3.65
2.98
3.27
3.53
2.82
2.04
2.78
3.54
4.00
2.93
3.27
3.72
4.73
4.43
3.90
4.12
TABLE 2
Dispersion Parameter Coefficients and Exponents
ฐz = a xb
Range of x C Stability C/D Stability D Stability
(meters) a b a b a b
<500 0.1120 0.9100 0.1078 0.87645 0.0856 0.8650
500-5000 0.1014 0.9260 0.1725 0.80072 0.2591 0.6869
>5000 0.1154 0.9109 0.3546 0.71611 0.7368 0.5642
D-13
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to Pasquill's C, D, and something between C and D (Pasquill, 1962;
Turner, 1967) so the notation: C, D, C/D is used to designate these.
The coefficients and exponents for various downwind distances from
the source, x, for these three stabilities used to determine a from:
z
az = axb (4)
are given in Table 2.
For application of the Gifford '72 model, the mean wind speed for
La Guardia Airport for the year 1969 as given by the Local Climatological
Data (Environmental Science Service Administration, 1969) of 11.6 miles
per hour (5.1852 m sec"^) was used. As indicated, Gifford (1972) is
not clear as to the size of the area that should be considered for
averaging area emission rates. Therefore, three distances were
selected: 3, 5, and 10 km. Using the emission rates for the area
sources on the 1 km basis previously prepared as part of the CDM run,
a computer calculation was made to determine average emissions for
both SOg and particulate within circles centered on each receptor for
radii corresponding to the three above-mentioned distances. If the
center of a 1 km source square was within the circle, it was included
in the averaging; if the center was outside, it was not included.
After determining the average emission rate for the three different
radius circles, the linear correlation coefficient of measurements of
concentration as a function of average emission rate was determined
D-14
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for both pollutants. This appears on the left side of Table 3. From
these results, the average emission rates for circles with a radius of
10 km were selected for use in applying the Gifford '72 model. At a
later time the average emissions for larger circles and the corresponding
correlation coefficients were determined. These appear in the right
hand portion of Table 3.
Since Gifford indicates that the values of the factor C of 50 for
sulfur dioxide and 225 for particulate matter were determined without
consideration of any background values, no background was added to the
estimates from this model before comparing with measurements. Comparisons
of this model were made with measurements for both, estimates from
area sources only, and estimates from the area sources using this model
with estimates of concentration due to point sources as determined
from the CDM model added to the area estimates. (After noting the
results achieved with this model, a background of 35 was added for
particulate matter estimates for an additional comparison.)
In applying the Modified Hanna Model to this region, six ranges
of distances were used as shown in Table 4. From intermediate results
punched on cards during the determination of the average emission rates
for various sized circles, it was simple to determine the average
emission rates for the 5 annular areas. For application of the Modified
Hanna Including Source Height (Model 6), the average emission heights
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TABLE 3
Linear Correlation Coefficients of Measured Air Quality Data
with Average Emission Rate of Circles of
Given Radius about Each Receptor
Pollutant
Number of
Radius of
Emission
Area
(km)
Receptors
3
5
1*
20
30
40
Sulfur dioxide
75
0.73
0.79
0.81
0.85
0.78
0.70
Particulate matter
113
0.61
0.64
0.63
0.63
0.63
0.60
TABLE 4
Limits of Integration and Corresponding
Values of k from Equation (3)
i
XI
xu
^i
km
km
Model 5
Model 6
H = 0
H = 10
H = 30
Particulate
S02
1
0
3
163.468
50.331
30.715
2
3
5
12.264
12.133
11.844
3
5
10
19.344
19.183
18.993
4
10
20
23.551
23.053
22.97-
5
20
30
16.085
15.580
15.555
6
30
40
12.589
12.120
12.110
D-16
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of 30 meters for sulfur dioxi'de and 10 meters for particulate matter
were chosen as representative of effective heights of emission for
the New York region. (One could apply this model using different
effective heights of emission for various receptor locations, but
only one height for each pollutant was used here.) Using values of
the dispersion parameter, az> corresponding to C/D stability the
k.'$ were determined by integrating analytically over appropriate
distance ranges for use in Model 5 and using the oz's for C/D stability
and the above en v.sion heights, numerical integrations were performed
to determine the values of the factors, k. for use with Model 6.
These are also shown in Table 4. Values of background concentration,
b, of 0 and 35 were used for sulfur dioxide and particulate matter
respectively in equation (2).
STATISTICS USED FOR EVALUATION
To evaluate the various models, 12 different statistics were used.
One of these was the mean concentration for all stations. Considering
the error for each location to be defined as the calculated concentration
from the model minus the measured concentration, the root mean square
error and the mean absolute error were determined. As an Indication
of the range of errors at the individual measurement locations, the
largest negative error (underestimate), the largest positive error
(overestimate), and the range of errors (the largest positive error
D-17
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minus the largest negative error) were tabulated. Linear correlation
coefficients, the variance of the correlation (the square of the
correlation coefficient) and the slope and intercept of the least
squares line of regression between model estimates and the measured
values were also calculated.
Because of its importance to the meeting of air quality standards,
the error at the location with the highest measured concentration is
of interest as well as the maximum estimated concentration at any of
the measuring station locations.
RESULTS
The results of the comparison of model estimates with measurements
are given in Table 5 for sulfur dioxide and in Table 6 for particulates.
In addition to comparing the calculated AQDM estimates with measurements,
the Air Quality Management Branch had used the measured air quality
data to calibrate the AQDM. Considering the calculations without
background as the independent variable, the measurements as the dependent
variable, least square lines that are forced to have an intercept of 0
for sulfur dioxide and 35 for particulate matter were determined. The
slope and intercepts for these lines are given in Table 7. Using the
equations of these lines, "calibrated" concentration estimates were
determined from the calculated concentrations. This was done similarly
for all other models. The comparisons of these estimates with the
121
D-18
-------
TABLE S. NEW YORK - SULFUR OIOXIDE
MAX MEAS 3SO
MEAN NUM RMSE MEAN LARGEST LARGEST ERROR LINEAR VARI- INTtR- ERROR AT MAXIMUM
(MEAS BER(STO ABSOLUTE
NEGATIVE
POSITIVE
RANGE '
CORWEL.
ANCE SLOPE CEPT
POINT OF
ESTIHATEI
ฆ135) QEV
ERROR
ERROR
ERROR
WITH
MAXIMUM
CONC. AT
or
MEAS.
MEAS.
A MEAS.
MEAS
POINT
"72)
I AIR OUALITY DISPLAY MODEL (AOOM)
211 75 121
92
-87
310
397
0.89
0.79 0.45 31
112
566
(116)( 75)( 37)
( 28)
(-117)
( 74)
(191)
(0.89)
(0.79)(0.82)(31)
( -97)
( 310)
2 HEMATOLOGICAL DISPERSION MODEL 22)
(118)
(240)
10.82)
(0.67)(0.68)(56)
(-101)
1 329)
3C COM
-------
TABLE 6. NEW YORK - PARTICULATE MATTER
MAX MEAS ฆ lf>9
MEAN NUM RHSE
(MEaS BERISTO
* 82) OEV
OF
MF AS
*?3)
MEAN LARGEST LARGEST ERROR LINEAR VARI- INTER- ERROR AT maximum
ABSOLUTE NEGATIVE POSITIVE RANGE COMPEL. ANCE SLOPE CEPT POINT OF EST ImaTEO
r.RROR
ERROR ERROR
WITH
MEAS.
MAXIMUM
MEAS.
CONC. AT
A MEAS.
POINT
1
AIR QUALITY DISPLAY MODEL
IAOOM)
10? 113
36
28
-51
115
166
0.62
0.39 0.38 43
5
199
1
77)1113)<
21)
<
15)
( -60)
(
54)
(114)
(0.63)
(0.39)(0.62)(34)
( -48)
( 136)
?
CLIMATOLOGICAL oispersion
MODEL (COM)
74 113
22
16
-63
68
131
0.61
0.37 0.63 35
-48
135
{
76)<113)ซ
22)
(
15)
I -62)
(
74)
(136)
(0.61)
(0.37)(0.59)(37)
( -43)
( 141)
3
COM (SINGLE STABILITY)
3A
COM (0 STABILITY)
AS 113
?ซ
21
-60
98
15H
0.64
0.41 0.42 45
-6
165
(
74)(113) 1
22)
(
17)
( -67)
(
65)
(132)
(0.64)
(0.40)(0.57)(40)
( -39)
( 13?)
3B
COM
< 172)
6B
wITM com point estimates
67 113
25
19
-71
37
108
0.62
0.39 0.63 39
-53
141
<
73)(113)(
2ซ)
(
18)
( -691
(
S5)
(124)
(0.62)
(0.39)(0.54)(42)
( -39)
( 1591
-------
TABLE 7
Equations of Least Squares Lines (y=a+bx)
Used to Determine Calibrated Concentrations
Model
Sulfur
Particulate
Dioxide
Matter
b ' a
b a
1. AQDM
0.5478 0
0.6162 35
2. CDM
0.8330 0
1.0630 35
3a. CDM (D Stability)
0.5429 0
0.7452 35
3b. CDM (C Stability)
1.0790 0
1.4956 35
3c. CDM (C/D Stability)
0.7653 0
1.0637 35
4. Gifford '72
ฆ
A. Area only
1.6909 0
0.7430 35
B. With CDM point estimates
1.3435 0
0.6557 35
5. Modified Hanna
A. Area only
0.2746 0
0.6063 35
B. With CDM point estimates
0.2676 0
0.5512 35
6. Modified Hanna Including Source Height
A. Area only
0.9435 0
1.4594 35
B. With CDM point estimates
0.8265 0
1.1717 35
D-21
-------
measured concentrations are reported in Tables 5 and 6 in parentheses
with each model. Note that the "calibrated" estimates are compared
with the same measurements used for determining the calibration equations,
not with independent data. Although the development of the coefficients
for the Gifford '72 should not require the addition of a background
concentration, the estimated values from this model were also tested
_3
after adding a background of 35 ygm to the particulate values. These
results are reported in brackets in Table 6.
Models 1 and 2 (both AQDM and CDM) each require joint frequency
distributions of wind direction, wind speed, and stability. For the
CDM (single stability) only the frequency and mean speed for each
direction (Table 1) are required. For the last three models only the
mean annual wind speed is used although the effects of the point sources,
that are added 1n, have used the joint frequency distribution information.
Considering first the results for sulfur dioxide, for the mean
concentration for the 75 locations, Model 2 with 138, Model 3c with
139, and Model 6 b. with 127 are all close to the mean of measurements
of 135 pgm . Note that calibration causes all models to underestimate
the mean. For the root mean square error, Model 2 with 52, Models 3b
and 6b with 56 are examples. Six of the 11 models have a RMSE
less than the standard deviation of the measured values, 72 pgm .
D-22
-------
As expected, calibration reduces the root mean square error but in
some cases only slightly. The smallest mean absolute errors are from
Model 2 with 37 and Model 6 b with 38. Calibration reduces the mean
absolute error. The range of errors is lowest, 186 (-131 to 49), for
Model 4 b. Note that all correlations are quite close, ranging from
0.77 to 0.89. The error at the point of the maximum measurement varies
from an underestimate of 175 ygm"3 to an overestimate of 112 ygm"3,
ignoring the huge overestimates of Model 5. Model 3 a. with an over-
estimate of 13 ygm"3 has the least error. Calibration causes Model 6
b's overestimate of 11 ygm"3 to be smallest. The maximum estimated
concentration at a measurement point ranges from 180 pgm"3 to 577 pgm"3
(again ignoring Model 5) with Model 2's estimate of 368 closest to the
measured maximum of 350 ygm"3. Calibration improves some estimates
of the max, notably Model 6 b. with 361.
In the results for the particulate matter (Table 6) for the mean
concentration, the 80 ygm"3 from Model 5 a is closest to the mean of
all measurements of 82. Models 3a, 2, and 5b also are close. Calibration
improves the means from most of the models. For the root mean square
error, only Model 2 with 21 is less than the standard deviation of
measure*. ,articulate values of 23 ygm"3. With calibration, Models 1,
2, and 3a have RSME less than 23. For the mean absolute error, Model
2 with 16 ygm"3 is the smallest. With regard to the largest errors,
D-23
-------
the models are not greatly different if Model 5 is excluded. Model
2 has the smallest error range, 131. Generally calibration doesn't
have too much effect on the range of errors. The correlations are
not greatly different for the various models ranging from 0.57 to
0.66 although they are poorer than those for SO^. The variance is
about half those for SO2: 0.32 to 0.43 for particulate, 0.60 to 0.79
for SOg. This may be due, in part, to the difficulty in obtaining a
reliable emission inventory for particulate matter and in obtaining
representative measurements. The error at the point of maximum
-3
concentration is a slight overestimate of 5 ygm for Model 1 and a
_3
slight underestimate of 6 pgm for Model 3a. For the maximum
concentration at any measurement point, Model 3a with 165 and Model
4b. with 164 are near the maximum measured at any sampling station
of 169. Generally, calibration does not greatly improve the estimate
of the maximum. An exception is Model 3b. whose calibrated maximum
is 171.
CONCLUSIONS
There is no one model that is superior in all statistics. The
AQDM (Model 1) overestimates concentrations. Although we feel that
the use of the Holland plume rise equation contributes to this over-
estimation, it is not the only cause. Many measurements of air quality
are needed in order to calibrate the AQDM. This results in a low
D-24
-------
error but also, in this case, results in underestimated concentrations
for both the mean and the maximum.
The CDM (Model 2) gives a good estimate of the mean and maximum
for SO in this test, but somewhat underestimates the particulate
2 *
concentrations, particularly the maximum. It should be noted that
this is without a calibration, therefore no extensive measurement
network was required to obtain the result.
The CDM (single stability) with the dispersion parameters given
by the C - D stability class (model 3c) gives a better estimate of
the mean of all stations than of the other statistics. The errors
are somewhat larger than the full model. Like the CDM Model, the
CDM (C/D stability) overestimates the S02 maximum concentration but
underestimates the particulate concentration.
The Gifford '72 Model underestimates both the mean concentrations
and also the maximum SO,, but produces a good estimate of the particulate
maximum for this test region. Although the errors are somewhat larger
than with the other models, they are not greatly different considering
the degree of simplicity of this model over the preceding ones. The
addition of a background of 35 usฎ"3 for the particulate estimates
Improves the results of this model 1n most statistics with the exception
of the maximum concentration at any measurement point.
D-25
-------
The Modified Hanna Including Source Height seems to be an improvement
over the Gifford '72 Model with regard to means and errors but does not
perform as well on the maxima, overestimating SOg and underestimating
particulate. Note that there is a relatively close correspondence
between the CDM (C/D stability) and Model 6b in nearly all statistics
and for both pollutants.
Simple models using only mean annual wind speeds and emissions do
quite well compared to the more complex models. The input and the
calculations are simple. They do have limitations when trying to
use the results to apply control strategies. For the simple models
at each receptor there are two concentration estimates available:
that due to point sources and that due to area sources. Of the
more complex models (1 and 2), these data indicate a preference for
the CDM over the AQDM.
ACKNOWLEDGEMENTS
The authors are indebted to Herschel H. Slater, William M. Cox,
Russell F. Lee, and others of the Air Quality Management Branch for
the emission inventory and air quality data for the New York Region
and the results of the computations by the AQDM. They are also indebted
to Frank Gifford and Steve Hanna for their unpublished manuscript
indicating their recent studies of simple modeling, and to Lea Prince
and Dot Avent for their, valuable assistance.
0-26
-------
REFERENCES
Briggs, G. A., 1969: Plume Rise. AEC Critical Review Series. Oak
Rdiqe, Tenn., USA, Atomic Energy Commission, Division of Technical
Information, 81 p. (Available from NTIS as TID-25075)
Calder, Kenneth L., 1970: Some miscellaneous aspects of current urban
pollution models. Proc. of Symposium on Multiple-Source Urban
Diffusion Models, 13 p. US tnvir. Prot. Agency Air Pollution Control
Office Pub. No. *\P-86.
Calder, Kenneth L., 1971: A climatological model for multiple source
urban air pollution. Proc. 2nd Meeting of the Expert Panel on
Air Pollution Modeling., NAT0 Committee on the Challenges of Modern
Society, Paris, France, July 1971, 33 p.
Environmental Science Services Administration, 1969. Local climatological
data, New York, N. Y., La Guardia Airport.
Gifford, F. A., Jr., and Hanna, Steven R., 1971: Urban air pollution
modeling. Proc. 2nd International Clean Atr Congress. Edited by
H> Englund and W. I. berry, Academic Press, New York and London,
1146-1151.
Gifford, F. A., Jr., and Hanna, S. R., 1972: Modeling urban air pollution.
Atmos. Environ, in press.
Hanna Steven R 1971: A simple method of calculating dispersion from
urban a?ea'sources, .i A?r. Poll. Contr. Assoc., 21, 12, 774-777.
Holland J Z 1953: A meteorological survey of the Oak Ridge area.
554-559, Atomic Energy Comm., Report ORO-99, Washington, D. C.,
584 p.
Martin, Delance 0., 1971: An urban diffusion model for estimating
long tern average values of air quality. J. ftir Poll. Contr.
Assoc., 21_> 1,16-19.
Martin Delance 0 , and Tikvart, Joseph A., 1968: A general atmospheric
diffusion model for estimating the effects of air quality of one
or more sources. APCA Paper 68-148, Presented at 61st annual APCA
meeting, St. Paul Minn., June 1968.
Pasquill, F., 1962: Atmospheric Diffusion. London, D. Van Norstrand,
297'p."
D-27
-------
TRW Systems Group, 1969: Air quality display model. Prepared for
Department of Health, Education, and Welfare, Public Health
Service, Consumer Protection and Environmental Health Service,
National Air Pollution Control Administration, Washington, 0. C.,
Contract No. Ph-22-68-60. (Available from NTIS, Springfield, Va.,
22151 as PB-189-194)
Turner, D. B., 1967: Workbook on atmospheric dispersion estimates.
National Air Pollution Control Administration, Cincinnati, Ohio,
PHS Pub. No. 999-AP-26, 84 p.
Zimmerman, John R., 1971: Some preliminary results of modeling from
the air pollution study of Ankara, Turkey. Proc. 2nd Meeting of
the Expert Panel on Air Pollution Modeling, NATO Committee on the
Challenges of Modern Society, Paris, France, July 1971, 28 p.
Zimmerman, John R.,1972: The NATO/CCMS air pollution study of St.
Louis, Missouri. To be presented at 3rd Meeting of the Expert
Panel on Air Pollution Modeling, NATO Committee on the Challenges
of Modern Society, Paris, France, October 1972.
D-28
-------
APPENDIX E
ANNOTATED BIBLIOGRAPHY OF ACTIVITY
ALLOCATION PROCEDURES
-------
Batty, Michael. Recent Developments in Land Use Modeling: A Review
of British Research. Urban Studies. June 1972.
This paper is primarily a discussion of the development and application
of Lowry-type models in England. These models have dominated British
research and have been strongly influenced by A.G. Wilson's entropy-
maximizing framework. Wilson's framework, which explicitly identifies
spatial interaction in terms of stocks and flows of activities, provides
a strong theoretical basis for refinements of the original Lowry model.
Building on Wilson's work, British researchers have devised several
constraint procedures which are consistent with Garin's matrix solution
of the Lowry model.
Several Wilson-Garin-Lowry models with constraints have been tested
at the subregional and town levels in Britain.
Batty reviews the current research undertaken in England to address
the following problems:
0 The static equilibrium nature of model projections
The lack of feedback between the population and service
sectors and the basic sector
The slow convergence of the constraints procedure under
model Modification I
The basic-service definitional problems
Improved parameter estimation techniques
t The optimum level of aggregation for the model (both in terms
of level of analysis and level of data)
Batty concludes that the Wilson-Garin-Lowry formulation 1s flexible enough
to allow for the solution of the above problems and the incorporation of
other model refinements as current research introduces them.
E-l
-------
Berry, Brian J. L. The Retail Component of the Urban Model. Journal
of the American Institute of Planners. May 1965.
The author analyzes work done in Chicago to identify the structure
of retail markets in an urban area. He concludes that the correct ecological
units for measurement of retail market areas are not transportation zones
or census tracts, since they cut across market boundaries. Larger analysis
units, however, are more likely to capture the effects of the retail business
center on its market area. The most useful definition of market area is
seen to be the area in which a constant rate of accumulation of trips
with distance holds.
The author employs factor analysis to determine the nature of the
interdependencies among variables indicative of the size and complexity
of the retail centers. Variables tested include functions, establishments,
total center area, shopping center area, ground floor area, area of
trade area, median income, social class, family class, total competition,
planned competition, unplanned competition, ribbon competition, discount
competition, and population density.
The results of the factor analysis suggest that the number of
functions and their size are highly related to the population of the
market area area and the position of the retail centers in a hierarchy.
Other independent factors, which are identified by factor analysis, are
population of the trade area and the independent variables above are
regressed by Berry to produce estimates of retail market area size for
planned and unplanned centers.
Chapin, Stuart F., Jr., and Shirley F. Weiss. A Probabilistic Model for
Residential Growth. Transportation Research. December 1968.
Chapin and Weiss view urban land development as a dynamic process
involving priming actions such as the building of expressways and major
industrial parks which promote secondary actions such as the opening of
shops or the choice of residential locations. The authors have focused
E-2
-------
their efforts on the study of residential land use conversion and have
determined that the most influential factors in this process are marginal
land not in use, accessibility to work, and assessed value.
A Monte Carlo simulation technique (linear form without replace-
ment) is adopted by the authors to distribute the expected level of new
housing units to grid cells on the basis of attraction probabilities.
Assessed values are used in computing the initial attraction probabilities,
while density and housing value constraints are imposed to modify these
initial probabilities. Ten density-value classes for subdivided and raw
land are considered by the model.
After each simulation period, the attraction probabilities for each
grid cell are modified according to anticipated new priming actions and
the effects of the land market in the previous development period. The
model developed by Chapin and Weiss allocates discrete household units,
and the number of these units to be allocated in each simulation period
is exogenously specified.
The model is applied to Greensboro, North Carolina, for the years
1948-1960 with three-year simulation periods. The results indicate that
the model may be used as a tool for investigating the effect of different
land use development policies on residential location patterns. In the
future, the authors are hoping to develop submodels which simulate human
values and behavior patterns in order to better understand the primary
influences on location decisions.
Cripps, E. L. and D. H, S. Foot. A Land Use Model for Subregional
Planning. Regional Studies. December 1969.
Wilson's entropy-maximizing approach has been applied in a Lowry-
type model to several regions and towns 1n England. This paper is a
full description of the application of such a model to the Bedforshire
multinodal subreglon.
E-3
-------
The model, which strongly resembles the Urban Systems Model, is
calibrated and applied in order to allocate population and service
employment to 130 zones. Plots of actual and estimated activity are
included in the paper as well as statistical indicators of the fit.
From the trip tables produced by the model, desire lines of spatial
interaction are examined to ensure that trips between selected towns are
adequately simulated.
In general, the authors find that the model is able to produce the
existing activity structure of the subregion within a reasonable margin
of accuracy and that the small-area projections made by the model are
sensible. However, the authors note the limitations of the static
equilibrium form of the model in describing the process of urban growth
and development.
The activity allocation model applied in Bedfordshire has a second
shortcoming cited by the authors. The model treats locational factors
after the decision to move has been made. The authors contend that
there is a need for behavioral submodels which simulate the motivation
to move itself. They reveal that such work is already done by A.G.
Wilson using the same framework as the Bedfordshire model, and they
conclude that such research represents the proper focus for future
modeling of locational decisions.
Evaluation of Regional Economic Effects of Alternative Highway Systems.
Curtis C. Harris Associates, Inc. FHWA Report, January 1973.
This report summarizes the development and application of a national
econometric model which projects population, employment, income, investments,
consumption, and government expenditures by 1973 OBE regions. The model
contains system sensitive components which may be used to evaluate the
effects of alternative transportation systems on regional activity
E-4
-------
levels. These components are embodied in the transport shadow prices
which are derived by solving a linear programming algorithm for each
industry.
The transport shipping costs developed by Harris include truck and
rail operating costs. The treatment of these costs is of particular
interest because the future location of basic employment may be influ-
enced by the level of truck and rail service.
The calculation of rail rates is based on the mark-up of out-of-
pocket costs incurred by the carrier. Out-of-pocket costs include
terminal and line haul expenses averaged over an extended time period.
These costs do not include equipment depreciation rates and overhead
expenses. The mark-up factors which reflect revenue to out-of-pocket
ratios for each region, are derived from the Annual ICC publication,
Procedures for Developing Rail Revenue Contribution bฃ Commodity and
Territory.
The methodology for developing truck operation costs which are
sensitive to highway system changes relates ICC average operating costs
per mile at specific speeds to the TRANSNET network. The ICC operating
costs are adjusted to reflect the type of road and terrain and penalties
for driving through or around major urban areas. Five highway types are
considered:
Limited access - divided toll
t Limited access - divided free
Other divided
Principal through highways
Local connectors
These types are further divided Into four speed categories depending
upon the terrain.
E-5
-------
The speeds associated with the TRANSNET network reflect composite
automobile-truck speeds. Therefore, TRANSNET speeds are adjusted to
reflect average truck speeds by the following formula:
TS = .77IS
where:
TS = Average truck speed, including stops
S = TRANSNET composite speed
The truck operating cost per vehicle mile is calculated for each
state on the basis of the ICC cost-speed data and the TRANSNET link
truck speeds. The cost per vehicle-mile is then used in TRANSNET to
compute the minimum truck cost path between OBE regions.
In order to account for the friction of traveling through or around
urban areas, TRANSNET imposes time penalties, depending on the size of
the city. In the Harris study, these penalties are increased by two
minutes for truck travel and are converted to costs using the ICC median
hourly truck operating costs.
By substituting truck costs for speed and time data in TRANSNET,
the Harris study has developed a methodology which is sensitive to the
changes in the highway system. For example, truck operating costs may
be decreased by the upgrading of a highway or the building of a bypass
around an urban area. The major assumption that is made in developing
the truck cost methodology is that motor carrier rates will actually
adjust to reflect such improvements in the highway system.
Goldner, William. The Lowry Model Heritage. Journal of the American
Institute of Planners, March 1971.
This article is a review of the basic Lowry model and its descen-
dants. The structure of Lowry's original model is discussed, and tables
of the Pittsburgh calibration parameters, allocation weights, and minimum
E-6
-------
service employment thresholds are presented. The subsequent theoretical
and operational revisions of the Lowry model discussed by Goldner are
summarized in the following tree:
Lowry Model (1962)
w/Rand for Pittsburgh
TOMM (1964)
Crecine for
Pittsburgh
TOMM II (1968)
Crecine for
Metro Project
Univ. of Mich.
BASS I (1965)
Goldner & Graybeal
at Berkeley
CLUG (1966)
Feldt
Cornel 1
Garin-Rogers
Contributions (1966)
1
f
PLUM (1968)
Goldner
for
San Francisco
~
A.G. Wilson
Contributions (1968)
at Center for Environmental
Studies, London
~
Urban Systems Model
Christopher Turner
at
Alan M. Voorhees & Associates
Under the aegis of A. G. Wilson, the Lowry model has been applied
at the subreglonal and town scale throughout England. Empirical work
-------
with the model in England has contributed meaningful improvements to the
original form.
Goldner maintains that the differences among Lowry-type models are
reflected in the following considerations:
Treatment of the time dimension
Degree of disaggregation
Handling of development constraints
Definition of the areal units
Number of variables considered
t Calibration and evaluation techniques
Goldner examines each of the Lowry model descendants with respect to
these model considerations.
Goldner concludes that the "promise of meaningful operationally"
which characterizes the original Lowry model has inspired a host of
variants developed for various planning applications. Although many
Lowry descendants in America have failed to reach operationally, British
modelers have applied the model at "conceptual, experimental, and
operational levels."
Illinois River Basin Pilot Project. Argonne National Laboratory.
January 1973.
The socioeconomic/land use mathematical model (SELUM) which was
developed in conjunction with the Illinois River Basin project is similar
to the trend analysis technique used in Missouri. The methodology
suggested for projection and allocation of state activity levels involves
the identification of subregions in the state. These subregions are
defined on the basis of activity growth patterns over time, i.e., fast,
stagnant, and independent. Trend projections of activity are then made
by subregions, counties, and municipalities.
E-8
-------
The Illinois activity allocation methodology assumes that the more
aggregate projections are most accurate. Therefore, county trend projections
are normalized to the appropriate subregional projection, and municipality
totals are normalized to the adjusted county projections.
The most attractive feature of this simple state projection and
allocation methodology is its flexibility and ease of utility. Data
requirements are small. Data for several points in time are the only
requirement for the projection of any activity. In addition, the
processing of data is greatly facilitated by the package of manipulation
and analysis programs developed for the Illinois project.
Kilbridge, M. D., Robert P. O'Block, and Paul V. Teplitz. A Conceptual
Framework for Urban Planning Models. Management Science. February
1969.
The authors present a framework for classification of urban plan-
ning models which emphasizes the basic characteristics of the model
rather than the application. The basic elements which are evaluated
for twenty major models are:
Subject (land use, transportation, population, and/or economic
activity)
Function (projection, allocation and/or derivation)
Theory (i.e., market theory, location theory, gravity theory,
etc.)
Method (econometric, stochastic, mathematical programming, or
simulation)
The authors also address the problems inherent in model building
efforts including the lack of adequate data and urban theory to support
the construction of models which accurately reflect urban phenomena.
E-9
-------
King, Leslie J. Models of Urban Land Use Development. Models of Urban
Structure. Lexington, Massachusetts, Lexington Books, 1969.
This paper is a summary of methods for classifying urban develop-
ment models, as well as an evaluation of the most influential models
which have been constructed. The author reviews the model classifica-
tion schemes suggested by Harris, Kilbridge, et. al, Wilson, and Lowry,
and then introduces his own systems analysis framework. This framework
involves a ranking of models based on the level of abstraction which
characterizes the model. The ranking continuum ranges from empirical
observations to simulation techniques to mathematical analyses.
Empirical observations include such "models" as Burgess' concentric
zone theory and Hoyt's sector hypothesis. Simulation techniques include
both gaming models and Monte Carlo simulations. King describes the most
famous urban gaming models, such as CLUG, METRO, and CITY, and summarizes
the uses of Monte Carlo techniques in model building. The most abstract
technique, that of mathematical analysis, is used in many urban devel-
opment models, and the author describes the general algorithms of
POLIMETRIC, EMPIRIC, and Lowry-type models. Several normative models
are discussed, including the Herbert-Stevens linear programming formu-
lation, and significant stochastic approaches are reviewed briefly. The
final recommendations of the author are addressed to agencies of small
metropolitan areas and these include:
Delineate specific goals with respect to land use development
Implement (even a simple linear regression) forecasting model
Consider participation in an urban simulation game
E-IO
-------
Model for Allocating Economic Activities into Subareas in a State.
Alan M. Voorhees and Associates, Inc. McLean, Virginia. Report for the
Connecticut Interregional Planning Program. May 1966.
A differential shift model is developed to allocate manufacturing
employment, population, and service employment by type to small areas.
The model is a set of simultaneous equations with independent variables
which include lagged dependent variables, holding capacities, and
accessibilities. The differential shift, which is the dependent variable
for each activity type, is added to the proportional share of state
growth term in the net change in small area activity over the forecast
interval. The model is applied in distributing activity to 169 Connec-
ticut towns, while a second set of similar models is applied to distribute
activity from towns to 804 traffic zones.
Readings in Economic Geography. Smith, Robert H. T., Edward J. Taaffe,
and Leslie J. King (eds.). Chicago, Rand-McNally and Company, 1968.
This book is a collection of classical and modern readings in
location theory. The sections of most interest with respect to the
development of a state activity allocation model involve discussions of
Central Place Theory.
In an early section, Brian J. L. Berry and Allan Pred discuss W.
Christaller's classical formulation of Central Place Theory. Chrlstaller
maintains that regions are characterized by a system of central places
whose arrangement 1s ordered on the basis of three competing principles;
namely, marketing, administration, and transportation. Chrlstaller also
hypothesizes that the range of a good 1s determined by the size of the
center, the Income of the consumer, subjective economic distance and the
quantity and price of the good.
John E. Brush presents results of an empirical study of Southwestern
Wisconsin which support many tenets of classical Central Place Theory.
E-U
-------
The settlements or trade centers in the study area are ranked as hamlets,
villages, or towns, according to the number of trade functions which
they perform and their spatial location. Brush concludes that trade
centers in Southwestern Wisconsin are distributed in a radial-circular
fashion, supporting the central place hypotheses of Kolb rather than
those of Christaller. Brush maintains that trade center hierarchies in
America differ from those in Europe and Africa. However, he concludes
that it may be possible to formulate hierarchy guidelines which are
applicable to similar regions in America.
Two other articles dealing with applications of Central Place
Theory are of special interest. A set of general equations is presented
by Berry and Barnum to summarize the fundamental characteristics of
central places. Specifically, the relationships between the trade area,
the population served, and population densities are plotted for four
regions. In a second article, Barry, Barnum, and Tennant's application
of Central Place Theory to Southwest Iowa suggests that factor analysis
is a useful tool for determining the hierarchy of central places.
A Review of Operational Urban Transportation Models. Peat, Marwick,
Mitchell, and Company. Final report submitted to FHWA, April 1973.
This document is a summary of operational urban transportation
procedures including five major activity allocation models: PLUM, USM,
EMPIRIC, Accessibility-Opportunity, and UPM. The comparison of activity
allocation models is preceded by a discussion of the appropriate evaluation
criteria and these are considered to be:
Conceptual structure
Solution method
t Policy sensitivity
Level of detail
Transferability
Man-machine interface
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Each of the five models is evaluated with respect to these criteria.
The major advantages and disadvantages of each model, as cited in the
report, are summarized below.
PLUM or the Projective Land Use Model is a static equilibrium
Lowry-type model with a deductive theoretical base. PLUM provides an
option for highly disaggregate output (if stratified input data is
available) and a land use accounting system is integrated into the
structure of the main model. Submodels are also available in the PLUM
package for the projection of socioeconomic data. PLUM suffers from the
same disadvantages as other Lowry models in that the basic-service
employment split is difficult to determine and the model requires
exogenous allocation of forecast year basic employment by small areas.
In many respects, the USM or Urban Systems Model is similar to
PLUM. It also is a Lowry-type, static equilibrium model, and therefore
has a tight, theoretical structure. However, the USM has a simple and
more clearly defined calibration process than PLUM due to its repeated
application and modification in Britain. The USM does not contain an
explicit land use accounting procedure, nor is the current form of the
model able to produce disaggregate activity types. The general limitations
of Lowry-type models are discussed above. These drawbacks are also
applicable to the USM.
EMPIRIC is a completely different type of model from the preceding
two in that its theorectical base is, at the same time, quite loose and
flexible. The basic structure of the model is a set of 3-15 simultaneous
equations, depending on data availability and desired disaggregation of
the output. The dependent variables in these equations represent
changes in shares of activities over the forecast Interval. The esti-
mation of coefficients for the model variables 1s a complex procedure
which requires a highly trained analyst. However, the package of data
manipulation programs which accompanies the basic model facilitates the
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calibration process. EMPIRIC activity output is generally disaggregated,
i.e., population by income group and employment by SIC group, and subordinate
models are available for projecting land consumption and socioeconomic
variables.
The Opportunity-Accessibility Model has a similar structure to that
of the basic modules of PLUM and the USM. The model has been used
primarily in allocating trip ends for transportation studies in urban
areas. Because of its principal use as an impact analysis tool, its
input data requirements are relatively small, and its output is of an
aggregated form. Its simplified structure precludes the testing of non-
transportation policies, an option which is available within the other
four models. Transferability of the model is limited, since it is not
actively supported by a staff effort.
The UPM or Urban Performance Model is a time-dependent model with
an attractive conceptual structure based on utility theory. The model
is principally noted for its use of "opportunity" and "quality" measures
which provide a simple and effective framework for the evaluation of
urban area projections. Some UPM forecasting options have not been
fully tested, however, and the calibration process is not well defined.
Therefore, the utility of the UPM in terms of producing urban area
projections is as yet unknown.
STAM Socioeconomic and Land Use Data File. West Virginia Department of
Highways. March 1972.
West Virginia is developing a comprehensive 1970 socioeconomic and
land use data base as part of a Statewide Traffic Assignment Model
Study. The socioeconomic variables which are being collected at the 778
zone levels can be allocated to the following seven categories:
Population
Auto Registration
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Employment
Indices of Productivity
t Education
Indices of Community Structure and Accessibility
Recreation Index
Work sheets and detailed instructions for implementing the data
collection process are provided in the West Virginia Manual.
A Summary of the Urban Systems Model. Alan M. Voorhees and Associates,
Inc., McLean, Virginia. January 1974.
The Urban Systems Model (USM) is a Lowry-type model which incor-
porates the entropy-maximizing formulation developed by A. G. Wilson.
The model consists of an integrated set of activity system submodels
which distribute population and service employment to small areas in a
metropolitan region as a function of:
The transportation cost (in terms of time or money) of traveling
to the small area
The intrinsic attractiveness of the small area to population
or service employment
The competitive attractiveness of all other such small areas
The activity holding capacity of each small area
Assuming regional projections of population, primary and service
employment, and a small area distribution of primary employment, the USM
operates iteratively to distribute increments of employment from work
place to residential locations and of service demand from residences and
work places to service centers. This iterative procedure converges on
the regional population and service employment control totals. After
regional convergence is attained and small area holding capacities are
satisfied, small area densities, accessibilities, and market potentials
are calculated for each activity.
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In addition to the calculation of the aforementioned indices, the
USM has the optional capbility of calculating the following environmental
indices:
Level of sewer service per resident and per primary employee
Level of water service per resident and per primary employee
Mobile source emissions (i.e., highway and transit) by district
Mobile source air pollution exposure indices (i.e., highway
and transit) by district
Noise pollution exposure levels from large stationary sources
(e.g., airports) by district
The USM is a static equilibrium model, which is operated recursively
(generally in ten-year periods) to predict activity distributions for
future points in time. The temporal dimension is treated implicitly in
the model via the usage of logged residential and service employment
attraction indices. The model may also be applied in a semi-dynamic
form to distribute the growth in activity during the forecast interval.
The USM has been calibrated and applied in the North Central Texas
(Dallas-Ft. Worth) and Baltimore regions, is being calibrated for
Kalamazoo, Michigan, and is also be adapted for application at the
statewide level in Connecticut.
Correlation coefficients (R2) and root mean square error are
calculated by the USM and provide statistical measures of the overall
quality of calibration results. The calibration procedure also provides
a comparison of the actual and estimated levels of population, service
employment, and total employment by small area. Analysis of the North
Central Texas calibration results show close correlation between actual
and estimated population, service employment, and total employment and a
good bit between the actual and estimated distributions of percent work
trips against travel cost.
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Wilson, A. G. Entropy in Urban and Regional Modeling. London, Pion
Limited, 1970.
This reference represents a synthesis of the work done by Wilson in
developing an entropy maximizing approach to spatial interaction within
an urban system. Wilson addresses the specific relationship of the
entropy-maximizing approach to transport models and locational analyses.
The gravity model, which has usually been derived thorugh analogies
with Newtonian mechanics, is derived by Wilson using a statistical
approach. The basic gravity model he produces is shown to be applicable
in a variety of transport flow situations.
In addition, Wilson demonstrates that the entropy-maximizing approach
can be applied to locational models which describe macro-system movements.
For example, the location of retail activity and residences may be
ascertained via Wilson's approach. However, the author concedes the
maximum entropy approach is probably not suitable in projecting discrete
industrial locations.
Wilson also discusses the close relationship of the entropy-maximizing
approach to input-output economic models and utility-maximizing systems
and concludes that the theory is quite adaptable in the field of urban
and regional modeling.
Wilson, A. G. Models in Urban Planning: A Synoptic Review of Recent
Literature. Urban Studies. November 1968.
The paper presents a systems framework for the design and implemen-
tation of planning models. Wilson presents the following hierarchical
relevance tree for planning*
Policy
t Action
Goals
Evaluation
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Design
Plan Formulation
Design Techniques
Problem Formulation
Understanding
Systems Models
Techniques
The author suggests that the most current model building efforts
belong to the Understanding stage, but that the future development and
application of models should involve both the Design and Policy levels.
Wilson proposes that the following basic questions be addressed
during the model development phase:
What questions is the model trying to answer?
Which concepts are measurable?
What variables are at least partially controlled by the planner?
What level of analysis and disaggregation will be used?
How will time be treated in the model?
What behavioral theories will the model represent?
What techniques are available for implementing the theories?
What relevant data are available?
How is model to be calibrated and tested?
Wilson delineates the following urban systems and discusses the
most recent modeling work in these areas:
Spatially aggregated population
Spatially aggregated economic
Residential
Workplace
Physical infrastructure
Economic activity
t Transport
Social services
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The remainer of the paper is a review of recent modeling contribu-
tions in each of the Policy and Design categories of the planning relevance
tree.
Wisconsin Place Classification for Transportation Planning. State of
Wisconsin, Department of Transportation, Division of Planning Januarv
1973.
Wisconsin has developed a framework for ranking activity centers
via a composite index of economic importance. Activity centers are
classified by the following six identifiers:
Urbanized area
Metropolitan center
t Regional center
District center
Area center
Special center
The classification procedure is based on the activity center ranking
as determined by the following variables: full valuation, sales tax,
population, employment, selected services, retail sales, and wholesale
trade.
The place classification methodology has been applied in ranking
Wisconsin activity centers in 1966 and has been updated for 1970. These
rankings have been used in determining the level, location, and type of
airports and highways needed in the prime market centers of the state.
It is anticipated that the place classification will also be useful in
the development of a statewide development and/or land use plan.
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