United States
Environmental Protection
Agency
Office of Air Quality
Planning and Standards
Research Triangle Park, NC 27711
EPA-454/R-92-005
November 1992
Air
EPA
GUIDELINE FOR MODELING
CARBON MONOXIDE FROM
ROADWAY INTERSECTIONS
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EPA-454/R-92-005
GUIDELINE FOR
MODELING CARBON MONOXIDE FROM
ROADWAY INTERSECTIONS
U S Environmental Protection Agency
Region 5, Library (PL-12J)
77 West Jackson Boulevard, 12tn rioor
Chicago, IL 60604-3590
U.S. Environmental Protection Agency
Office of Air Quality Planning and Standards
Technical Support Division
Research Triangle Park, North Carolina 27711
November 1992
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DISCLAIMER
This report has been reviewed by the Office of Air Quality Planning and Standards,
U.S. Environmental Protection Agency, and has been approved for publication. Any mention
of trade names or commercial products is not intended to constitute endorsement or
recommendation for use.
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TABLE OF CONTENTS
List of Figures iv
List of Tables v
Acknowledgments vi
1 Introduction 1-1
1.1 Overview 1-1
1.2 Background 1-3
1.3 Scope of Intersection Analyses 1-6
2 Receptor Siting 2-1
2.1 Receptor Site Selection 2-1
2.2 Criteria for Siting Intersection Receptors 2-1
3 Intersection Selection Procedure ..3-1
3.1 Rationale 3-1
3.2 Level-of-Service Determination 3-1
3.3 Ranking and Selecting Intersections 3-3
4 Intersection Analysis 4-1
4.1 Evaluation Overview 4-1
4.2 Project/Intersection Description (Step 1) 4-2
4.3 Air Quality Objectives (Step 2) 4-4
4.4 Assembly of All Data (Step 3) 4-4
4.5 Multiple Intersection Ranking (Steps 4 through 12) 4-4
4.6 Individual Intersection Analysis (Steps 13 through 18) 4-6
4.7 Input Data Selection 4-6
4.7.1 Ambient Conditions 4-7
4.7.2 Estimating 8-Hour Concentrations from 1-Hour Concentrations . . 4-11
4.7.3 Background Concentrations 4-12
4.7.4' Other Input Data 4-12
5 Examples 5-1
5.1 Example of a SIP Attainment Demonstration 5-1
5.1.1 Ranking by Volume and LOS 5-2
5.1.2 Emissions Modeling 5-4
5.1.3 Dispersion Modeling 5-8
5.2 Example of a Project Level Analysis 5-13
6 References 6-1
iii
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LIST OF FIGURES
Number Page
2-1 Example receptor siting on one intersection approach 2-4
4-1 Overview of intersection evaluation procedures 4-3
5-1 MOBILE input file used in the example 5-6
5-2 MOBILE output file for the input file listed in Figure 5-1 5-7
5-3 Geometric layout of Main St. and Local St. for example intersection 5-9
5-4 The CAL3QHC model input file used for the SIP attainment example 5-10
5-5 The CAL3QHC model output file for the SIP attainment example 5-11
5-6 The CAL3QHC model input file used for the project level example 5-14
5-7 The CAL3QHC model output file for the project level example 5-15
IV
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LIST OF TABLES
Number Page
4-1 Surface Roughness Lengths (z0) for Various Land Uses 4-10
4-2 Free Flow Speeds for Arterials 4-15
4-3 Arterial Class According to Function and Design Category ". . . . 4-16
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ACKNOWLEDGMENTS
The draft version of this document was prepared for the U.S. Environmental Protection
Agency (EPA), Office of Air Quality Planning and Standards, under Contract No. 68-02-4394
by George Schewe of PEI Associates, Inc., Cincinnati, Ohio. The draft document was subject
to public review and comment through inclusion in Docket A-88-04 on the Fifth Conference
on Air Quality Modeling. The final version of this document, which responds to the public
comments, was prepared under Contract No. 68D90067 by Donald C. DiCristofaro of Sigma
Research Corporation, Concord, Massachusetts. Mr. Guido Schattanek of Parsons Brinckerhoff
Quade and Douglas, Inc. of New York, New York provided comments regarding the final
document Special thanks are given to Thomas Braverman, the EPA Technical Director, for
his guidance and assistance in resolving technical issues.
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SECTION 1
INTRODUCTION
1.1 Overview
This guideline is designed to evaluate air quality impacts at one or more roadway inter-
sections where vehicular traffic will cause or contribute to increased emissions of carbon
monoxide (CO). The explicit purpose of this guideline is to provide a consistent, scientifically
acceptable method for estimating the air quality impacts of vehicular traffic at intersections to
determine if such impacts may exceed the National Ambient Air Quality Standards (NAAQS)
for CO. The NAAQS for CO are as follows:
Averaging Period NAAQS (ppm)
1 Hour 35
8 Hour 9
This guideline is appropriate for project level analyses in accordance with State
Implementation Plans (SIPs), including conformity analyses. This guidance may also be used
for Environmental Impact Statements (EISs). Development projects such as street and
intersection reconfigurations, mall constructions, and other construction projects that could
significantly affect traffic patterns will require air quality impact assessment. For such studies,
the effect of the project on traffic, congestion, and subsequent air quality impacts must be
studied. This guideline offers guidance for applying dispersion and emission modeling
techniques for such analyses.
For SIP evaluations and urbanwide studies, the procedures in this guideline should be
used in conjunction with an areawide model. This combined modeling technique will allow.
the determination of areas that may be in violation of the CO NAAQS, best suited locations
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for monitor siting, control strategy evaluations, and air quality characterization over broad
geographic areas as input to population exposure studies.
The original EPA guidance for intersection CO modeling was to use the Carbon Mon-
oxide Hot Spot Guidelines (EPA, 1978a) or the Guidelines for Air Quality Maintenance Plan-
ning and Analysis Volume 9 (Revised): Evaluating Indirect Sources (EPA, 1978b) (hereafter
referred to as Volume"9) for intersection screening. If the results of screening modeling
showed a potential for exceedances of the CO NAAQS, then refined analysis of intersections
was necessary using Worksheet 2 of Volume 9 for traffic and emissions input to CALINE3
dispersion. Both "the Hot Spot Guidelines and Volume 9 have been criticized as being
outdated, inadequate, and difficult to use. These techniques are considered outdated for the
following reasons:
° The major emissions component is the modal emissions factors which are based
on pre-1977 vehicles.
0 The correction factors to the modal emissions model are from the MOBILE1
emissions model which has been updated to the MOBILES emissions model
(EPA, 1992a).
° The traffic component is based on the 1965 Highway Capacity Manual (HCM)
which was updated in 1985 (TRB',1985).
These techniques are considered inadequate because they cannot handle overcapacity
intersections and are considered difficult to use because they are in a workbook format rather
than executable on a personal computer.
The guidance in this document updates the intersection techniques presented in Volume
9. The intent of this guideline is to provide techniques that reflect the current state of
emissions calculations (MOBILES Emissions Model) and traffic flow and delay (1985 High-
way Capacity Manual (HCM)). The EPA has completed studies to evaluate CO intersection
modeling techniques (EPA, 1992b). Based on the results of these studies, the CAL3QHC
(Version 2.0) model (EPA, 1992c) has been selected as the recommended CO intersection
model in the Guideline on Air Quality Models (Revised) (EPA 1986). for .intersection
modeling. CAL3QHC contains the CALINE3 dispersion model and utilizes procedures in the
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1985 Highway Capacity Manual to calculate queue length. The latest version of the MOBILE
emissions model is used to calculate emissions input to the CAL3QHC model. Guidance is
provided for the modeling of intersections in the form of CAL3QHC input specifications and
application techniques.
1.2 Background
Air quality modeling has long been used to estimate CO concentrations at many
locations throughout the country. Its primary use has been for analysis at the highway project
level. Air quality modeling analyses for highway projects are performed to estimate the air
quality pollutant concentrations that will result from the project. Modeling has also been used
to aid in siting monitors. Intersection modeling has been useful in screening suspected areas to
determine candidate monitor sites for worst case CO air quality. Urban area modeling has
been used in some instances to aid in the siting of background monitors. In addition, urban
area modeling has been used to evaluate the effects of control strategies for State
Implementation Plans and to obtain population exposure estimates.
A number of CO models have been utilized for project level analyses. The Guidelines
for the Review of the Impact of Indirect Sources on Ambient Air Quality, Volume 9:
Guidelines for Air Quality Maintenance, Planning, and Analysis (EPA, 1975a), released in
1975, contains the first EPA recommended technique for project level analysis. This document
contains procedures on estimating CO potential concentrations from hot spots such as
congested intersections. The traffic component of the Volume 9 procedure is based on the
1965 Highway Capacity Manual (HRB,1965), emissions on the Modal Emissions Model
(EPA, 1974), and dispersion on the HIWAY model (EPA,'l975b). In 1978, EPA released a
revised version of Volume 9, entitled Guidelines for Air Quality Maintenance Planning and
Analyses Volume 9 (Revised): Evaluating Indirect Sources (EPA, 1978b). The revised version
was similar to the earlier version, except that it required more input data be provided by the
user.
Also in 1978, the EPA released the Carbon Monoxide Hot Spot Guidelines (EPA,
1978a). These guidelines, also based on the 1965 Highway Capacity Manual, Modal Emis-
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sions Model, and HIWAY dispersion model, contain a number of procedures of varying com-
plexity for highway project analyses. The screening procedure is the easiest to use because it
requires the least input. It indicates whether a project has the potential to exceed the CO
NAAQS, although it does not estimate concentrations. To obtain concentration estimates, the
verification procedure must be utilized. This procedure provides a more thorough evaluation
of hot spots than does the screening procedure using physical and operating characteristics
specific to a location. Greater data requirements must be provided by the user of the
verification procedure, although requirements are still not as demanding as with Volume 9.
The screening and verification procedures of the Carbon Monoxide Hot Spot Guidelines
and Volume 9 are in a workbook format. The Intersection Midblock Model (IMM)
(NYSDOT, 1982), a computerized model originally part of the Carbon Monoxide Hot Spot
Guidelines, is based on the same principles as the verification procedure, but it allows added
flexibility in performing an analysis because it is totally computer based. It has since been
modified by the State of New York, including- one modification that updated the HIWAY
Model dispersion component with the HIWAY-2 Model (EPA, 1980).
Several states have developed their own models for project level analysis. The models.
TEXIN and its update, TEXIN2 (Bullin et al., 1990), were developed by Texas in 1983 and
1987, respectively; the Georgia Intersection Model (GIM) (EMI Consultants, 1985) was devel-
oped by Georgia in 1985; the CAL3Q model was developed by EPA Region I in 1987; and
successive versions of the CALINE model were developed by California, with CALINE3
(Benson, 1979) in 1979 and CALDSTE4 (Benson, 1989) in 1984. Most of these models have
been used in areas of the country outside the state in which they were originally developed. It
should be noted that CALINE3 is simply a dispersion model and does not contain an emissions
or traffic component as do the other models mentioned. In fact, the dispersion component of
these other models is essentially CALINE3 with, in some cases, very minor modifications.
Because of its widespread use nationally, CALINE3 became the EPA recommended
dispersion model for highway project level analysis in 1986. It produces comparable
concentration estimates to HIWAY-2. In addition, there have been a number of criticisms
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raised with the traffic and emissions components of the Volume 9 and Carbon Monoxide Hot
Spot Guidelines procedures. The EPA has completed studies to evaluate CO intersection mod-
eling techniques (EPA, 1992b). Based on the results of these studies, the CAL3QHC (Version
2.0) model (EPA, 1992c) has been selected as the recommended CO intersection model in the
Guideline on Air Quality Models (Revised) for intersection modeling. CAL3QHC contains the
CALINE3 dispersion model and utilizes procedures in the 1985 Highway Capacity Manual to
calculate queue length. The latest version of the MOBILE emissions model is used to calcu-
late emissions input to the CAL3QHC model.
In an urban area, sources of mobile emissions are especially widespread. Ambient
concentrations of CO may be high near locations where vehicles tend to accumulate, slow
down,.and idle for a period of time (e.g., at an intersection). The extent of this problem is a
direct function of the number of vehicles, their operating mode, their movement, and the length
of delay. Thus, the CO distribution across an urban area is not only a function of the
distribution of major urban development in the area, but also of individual intersection, street,
and traffic characteristics-
Mobile source emissions and air quality impact studies have been the subject of
numerous State Implementation Plans and new highway/intersection impact studies in various
parts of the United States. The scope of these studies has ranged from modeling (simplified
rollback and detailed dispersion modeling analysis) to roadside monitoring programs. The
increased understanding of the potential emission contributors (i.e., mobile sources) has
allowed the development of reasonable and representative emission and dispersion modeling
techniques. These techniques use specific data pertaining to the vehicles, traffic, and roadway
configurations at an intersection. Some of the existing models are easy to use and provide a
simplified characterization of vehicles and roadways by combining factors into conglomerate
effects. Other techniques require the detailed discernment of individual roadway segments or
link components, vehicle emissions by operating mode, and integration over link lengths.
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This guideline recommends the use of the CAL3QHC (Version 2.0) model for intersec-
tions and the combined use of CAL3QHC (Version 2.0) and areawide models for overall urban
area analysis.
Either the Urban Airshed Model (UAM) (EPA, 1990) or the RAM model (EPA, 1987)
is recommended for urban area CO modeling. Exceedances of the CO NAAQS often occur
during the period beginning with the evening rush hour traffic and extending to about midnight
on cold, clear nights with strong nighttime radiation inversions and light and variable winds.
Under these conditions, motor vehicle and other emissions, such as wood smoke, are trapped
under the inversion. The rapid change in mixing height and stability combined with light and
variable winds often lead to high CO concentrations that can be handled better by the UAM
than the RAM model. The UAM is a numerical model that provides better treatment of the
time-dependent change in meteorological conditions than the Gaussian RAM model. However,
the UAM is a complex model to execute since it requires a great deal of input data, some of
which are difficult to obtain. Thus, although the UAM is better able to handle the conditions
leading to GO exceedances than the RAM model, the UAM is more resource intensive,
difficult to execute, and costlier than the RAM model. Because of the high cost of collecting
input data for and executing the UAM, it is routinely used to evaluate several high CO
episodes in an urban area. Because the RAM model uses standard National Weather Service
data for an entire year, it provides CO concentrations for each hour of an entire year.
1.3 Scope of Intersection Analyses
Evaluation of the air quality impact of an intersection requires adding the incremental
impact of the intersection to background ambient levels at the site and then comparing the total
with the NAAQS. The background CO concentrations are due to areawide mobile and
stationary sources of emissions. Emphasis in this guidance document is on intersections.
Intersections for analysis will be selected from those intersections whose conditions are sus-
pected to be the most conducive to high concentration impacts. For project level analyses, the
criteria for intersection modeling depends on whether the project has the potential to create an
adverse air quality.impact by either significantly increasing traffic or reducing distances from
receptors where the public has general access.
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The calculation of air quality impacts for intersections depends on the hour of the day,
the day of the week, the month or season, the year of analysis, and the averaging time of
concern. These factors affect both the traffic and emissions calculations. Generally, the
highest concentrations would be expected during the peak hour of traffic. The peak hour traffic
conditions are defined as the average or typical values during the hour of the day which
usually records the peak hour traffic, rather than the worst case traffic conditions for the entire
year.
An overall procedure is necessary for the consistent selection and analysis of inter-
sections. This procedure includes the following:
o The gathering of data related to the project of concern, including traffic and
operating characteristics, and roadway configurations and geometry.
o The screening of all intersections to determine the need for additional analysis.
° ' The ranking of all screened intersections.
o The computation of traffic flow conditions and emissions for intersections
requiring further analysis, based on both those vehicles moving through the
intersection without stopping (free-flow) and those that are delayed and stopped
(queued vehicles).
° The selection of receptor locations.
o The use of dispersion models to calculate estimated concentrations due to inter-
sections.
° The overall tabulation of total concentrations due to the intersection and
background.
To provide guidance on the performance of the procedures outlined above, this report is
divided into several sections that address each step of the evaluation of intersections. Section
2 provides procedures for selecting appropriate and reasonable receptor locations near intersec-
tions. Section 3 describes the procedure for ranking and selecting intersections for modeling.
Section 4 presents the overall intersection modeling procedures. Section 5 provides examples
and references are given in Section 6.
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SECTION 2
RECEPTOR SITING
2.1 Receptor Site Selection
The locations at which concentrations are estimated are known as receptors. As a
general rule, receptors should be located where the maximum total project concentration is
likely to occur and where the general public is likely to have access. This means that
receptors should be located at sites in the vicinity of those portions of the intersection where
traffic is likely to be the greatest and the most congested, e.g., along a queue.
2.2 Criteria for Siting Intersection Receptors
Much was written regarding the selection of reasonable receptor locations for air quality
impact analysis near intersections in the Volume 9 guidance (EPA, 1978b). The general
criteria for receptor siting expressed in the Volume 9 guidance included: 1) places of expected
1-hour and 8-hour maximum concentrations, 2) places where the general public has access over
the time periods specified by the NAAQS, and 3) reasonableness. Reasonableness is defined
in terms of proximity to the intersection, but not on the roadway itself. Both specific and
general locations are recommended for intersection analyses.
An objective of this document is to provide guidance for estimating maximum CO
concentrations near an intersection. Roadways are not potential receptor sites. In addition,
receptors should not be located within 3 meters of the traveled roadways which comprise the
intersection, where vehicle turbulence does not allow current models to make valid
concentration estimates. If there is a structure (i.e., building) within the 3 m zone, then the
EPA Regional Office should be contacted for a determination of proper receptor siting.
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To clarify what might generally be regarded as reasonable and unreasonable receptor
sites, a few examples are cited here.
1. Examples of Reasonable Receptor Sites
0 All sidewalks to which the general public has access on a more-or-less
continuous basis.
0 A vacant lot near an intersection, where the general public would have
continuous access in the immediate vicinity.
0 Portions of a nearby parking lot to which pedestrians have continuous
access.
0 In the vicinity of parking lot entrances and exits, provided a nearby area
contains a public sidewalk, residences, or structures to which the general
public is likely to have continuous access.
0 On the property lines of all residences, hospitals, rest homes, schools,
playgrounds, and the entrances and air intakes to all other buildings.
Within the context of these sites, the actual locations of the receptors should be
as follows:
0 At least 3 m from each of the traveled roadways that comprise the
intersection and at a height of 1.8 m; these apply in general to all re-
ceptors with further refinements below.
° Nearby occupied lot — nearest the edge within the lot to which the gen-
eral public has continuous access. If this cannot be determined, the
property line of the lot nearest to traffic lanes should be used.
0 Vacant lot ~ same as for occupied lot.
Sidewalks — present a problem in that the general public is unlikely to
occupy a relatively small portion of the walkway continuously.
Nevertheless, the general public does have access to the sidewalk as a
whole on a continuous basis. Thus, it is appropriate to consider the
whole sidewalk as a reasonable receptor site. For the analysis proce-
dures in this guidance, a receptor should be located at least 3 m from
each of the traveled roadways which comprise the intersection. If the
width of the sidewalk allows, it is recommended that receptors be placed
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at the midpoint between the curb and the building line. At a minimum
receptors should be located near the corner and at mid-block for each
approach and departure at the intersection. Receptors should be placed
on both sides of the road. For long approaches, it is recommended that
receptors be located at 25 m and 50 m from the intersection corner.
More receptors can be located where desired by the user.
Any location near breathing height (1.8 m) to which the general public
has continuous access.
2) Examples of Unreasonable Receptor Sites
0 Median strips of roadways.
0 Locations within the right-of-way on limited access highways.
0 Within intersections or on crosswalks at intersections.
0 Tunnel approaches.
0 Within tollbooths.
For most studies, receptors should be placed at each approach on both sides of where
the queues develop. In all cases mentioned above the receptors should be located on the
adjacent sidewalk or at the right-of-way limit if no sidewalk exists. An example receptor
siting of one intersection approach is shown in Figure 2-1.
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i
3m
3m
3m
3n
3m
3m
NOT DRAWN
TO SCALE
RECEPTORS
Figure 2-1. Example receptor siting on one intersection approach.
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SECTION 3
INTERSECTION SELECTION PROCEDURE
3.1 Rationale
This guidance provides a ranking and selection procedure to allow the discernment of
those intersections that could be potential hot spots, i.e., have high CO concentrations. The
guidance will be used primarily to determine potential hot spots in a SIP analysis, but will also
be useful for project level analysis when more than three intersections are affected.
Intersections are first selected for analysis on the basis of the study objectives. Study
objectives would include the characterization of potential CO hot spots for the development of
a SIP attainment demonstration or a conformity analysis of projects to the SIP. All signalized
intersections are reviewed for the potential to create an adverse air quality impact by either
significantly increasing traffic or reducing roadway distances from receptors where the general
public has access. The selection of intersections for modeling should be based on the ranking
procedure discussed in Section 3.3. The calculation of Level-of-Service (LOS) for use in the
ranking of intersections is discussed in Section 3.2.
3.2 Level-of-Service Determination
Level-of-Service (LOS) measures the operating conditions in the intersection and how
these conditions affect traffic flow and delay. The LOS is a measure of the combined traffic
volume, signal timing, and related congestion and delay. It is related both to the physical
characteristics of the intersection and to various operating conditions that occur when the inter-
section is carrying variable traffic volumes (Garber, 1988).
In a signalized intersection, LOS is defined in terms of vehicle delay time (TRB, 1985).
The Highway Capacity Manual (HCM) (TRB, 1985) states that LOS delay is:
"... a measure of driver discomfort, frustration, fuel consumption, and lost travel time.
Specifically, level-of-service criteria are stated in terms of the average stopped delay ..."
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The following synopsis of each LOS is given in the HCM.
Level-of-Service A - describes operations with very low delay, i.e., less than
5.0 seconds per vehicle.
Level-of-Service B - describes operations with delays in the range of 5.1 to
15.0 seconds per vehicle. More vehicles stop at LOS B than at LOS A, which results
in higher levels of average delay.
Level-of-Service C - describes operations with delays in the range of 15.1 to 25.0
seconds per vehicle. A significant number of vehicles stop at this level; however, many
still pass through the intersection without stopping.
Level-of-Service D - describes operations with delays in the range of 25.1 to 40.0
seconds per vehicle. At LOS D, the influence of congestion becomes more noticeable.
Many vehicles stop, and the proportion of vehicles not stopping declines.
Level-of-Service E - describes operations with delays in the range of 40.1 to
60.0 seconds per vehicle. This is considered to be the highest limit of acceptable delay.
Level-of-Service F - describes operations with delays in excess of 60.0 seconds per
vehicle. This is considered to be unacceptable to most drivers. This condition often
occurs with oversaturation, i.e., when arrival flow rates exceed the capacity of the
intersection.
Intersections with the same LOS can be ranked by degree of delay. As the Level-of-
Service decreases, volume-to-capacity ratios increase, progression of vehicles through the
intersection decreases, long vehicle queues occur, and idle emissions increase. As part of the
procedure for determining critical intersections, those intersections at LOS D, E, or F or those
that have changed to LOS D, E, or F because of increased volumes of traffic or construction
related to a new project in the vicinity should be considered for modeling. Intersections that
are LOS A, B, or C probably do not require further analysis, i.e., the delay and congestion
would not likely cause or contribute to a potential CO exceedance of the NAAQS.
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3.3 Ranking and Selecting Intersections
The following steps should be used for ranking and selecting intersections for
modeling:
1) Rank the top 20 intersections by traffic volumes;
•
2) Calculate the Level-of-Service (LOS) for the top 20 intersections based on
traffic volumes;
3) Rank these intersections by LOS;
4) Model the top 3 intersections based on the worst LOS; and
5) Model the top 3 intersections based on the highest traffic volumes.
It is assumed that if the selected intersections do not show an exceedance of the
NAAQS, none of the ranked intersections will. This assumption is based on the assumption
that these intersections will have the highest CO impacts and that intersections with less traffic
volumes and congestion will have lower ambient air impacts. Thus, if no exceedances of the
CO NAAQS occur for the attainment year when the results of the intersection modeling are
added to the urban areawide component of the CO concentration at the intersection, then the
CO attainment demonstration is complete. If CO exceedances do occur, then further controls
are necessary.
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SECTION 4
INTERSECTION ANALYSIS
4.1 Evaluation Overview
The analysis procedures in this guidance document are specifically designed for
screening analysis of signalized intersections using worst-case meteorological defaults. The
use of measured meteorological conditions for a refined analysis will be considered on a case-
by-case basis by the local EPA Regional Office. If the intersection modeling analysis is
combined with Urban Airshed Model (UAM) results for a SIP analysis, then the measured
meteorological conditions used by the UAM for temperature, wind speed, and wind direction
should also be used in the CAL3QHC model.
For a SIP areawide analysis, these intersection impacts should be considered together
with the contributions from areawide modeling. The areawide model should be the Urban
Airshed Model or the RAM Model. These models are used in urban areas to: 1) show
locations throughout the urban area with the highest areawide component of CO concentrations
and magnitude of these concentrations, 2) evaluate the effects of control strategies for SIPs, 3)
obtain characterization of ambient CO levels over broad geographic areas as an input to
population exposure models, .and 4) determine candidate sites for air quality monitors. As
mentioned above, when UAM is combined with CAL3QHC results, the same meteorological
conditions for temperature, wind speed, and wind direction should be used for both models.
The CAL3QHC model should be run using the UAM hourly temperature, wind speed, and
wind direction from the grid square where the intersection is located for each hour of the
episode being modeled. The UAM modeled concentration from the grid cell where the
intersection is located should be entered into the CAL3QHC model as the background
concentration to determine the total impact for each hour. The results should then be averaged
over 8 hours to determine the maximum 8-hour concentration.
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Figure 4-1 outlines the general evaluation procedures a user would follow if performing
a complete comprehensive analysis of multiple intersections, such as for a new project (i.e., a
mall or major roadway construction) that would affect traffic on nearby roads, or evaluating
intersection impacts for a State Implementation Plan (SIP). In the case where only a few or
one intersection is involved, ranking and selection may not be required and the analysis of all
sites under consideration may be important.
In Figure 4-1, the small number code in the upper left-hand corner of each box
corresponds to the steps described in this section. As shown, the steps that should be followed
are a logical sequence in the intersection evaluation procedure. For an individual intersection,
the modeling steps are the same except that ranking by volume and LOS are not required.
Each step is presented in detail in the following subsections.
4.2 Project/Intersection Description (Step 1)
Step 1 in this evaluation is to provide a good project or intersection related narrative,
including diagrams. In the preparation of an air quality impact assessment for a new roadway
project or evaluating existing intersections, a qualitative and quantitative description of the
traffic and physical characteristics is needed. If a new sports complex or mall is planned,
many existing roadways will be affected, and increased traffic will occur to service the facility
for events or business. A study of traffic and roadway design and planning will have been
performed by professional traffic engineers and planners to forecast the impacts on existing
and future traffic levels. The increased intersection and roadway demands translate into higher
potential air quality impacts than would have occurred without the project. For the assessment
and potential mitigation of intersections, a descriptive and informative overview of each
intersection is necessary. Such overviews would allow decision makers to arrive at informed
conclusions and interpretations regarding estimated air quality impacts and to form mitigative
measures to address potential "hotspots."
4-2
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CAL30HC
I Apply p«r-«lvtttnc«
Tactor ana background
119
Cdmparo rwcultB
witn NAAQS
•
Figure 4-1. Overview of intersection evaluation procedures.
4-3
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4.3 Air Quality Objectives (Step 2)
Determining the air quality objectives or goals of an analysis of air quality impact due
to an intersection is the next required step. The objectives will dictate the level of analysis,
the resources, and the amount of effort required. If a project permit review is involved, the
specific objective may be to assess the worst case potential for exceeding either the 1-hour or
8-hour CO NAAQS.
4.4 Assembly of AH Data (Step 3)
A data base is necessary to formulate inputs to the modeling procedure. Some items
that should be included in the data base are as follows:
0 A scaled map of the intersection and nearby approaches/departures.
0 Traffic engineering characteristics of each approach/departure to be analyzed,
i.e., number of lanes, road width, turning channels, type of intersection control,
and signal timing.
0 Through, turning, and total traffic volumes and speeds for each road for the
average peak hour traffic.
0 Link coordinates and specification of the coordinate origin.
0 Receptor coordinates.
0 Background and local CO air quality measurements.
0 Meteorological data, if areawide modeling using RAM or UAM will be
performed.
0 Miscellaneous demographic data, such as urban/rural characterization and diur-
nal roadway traffic patterns.
4.5 Multiple Intersection Ranking (Steps 4 through 12)
Whenever the study objectives and project scope require the consideration of many
intersections, steps 4 through 12 can be implemented. These steps provide a logical sequence
of analysis that permits a quick review of intersections to determine which are likely to have
the highest ambient air quality impacts based on the total volumes of traffic using the intersec-
4-4
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tions and the delay of traffic (level-of-service) calculations. These two factors, number of
vehicles and vehicle delay, are related directly to the emission production at the intersection
and therefore provide a direct indicator of related air quality impacts (concentrations are
directly proportional to emissions).
Step 4 is the identification of all signalized intersections of consequence identified in
Steps 1 through 3. Rank the top 20 intersections by traffic volumes in Step 5. In Step 6, for
the top 20 intersections ranked in Step 5, the user must calculate the level-of-service (LOS) for
each intersection. This may be accomplished by using the worksheet techniques for signalized
intersections given in Chapter 9 of the Highway Capacity Manual (HCM) (TRB, 1985) or by
using one of the 1985 Highway Capacity Manual personal computer software packages that
have been developed over the past several years. Basically, the level-of-service calculations
utilize the number of lanes, lane width, red time, green time, total cycle time, approach speeds,
lane capacities, turning movements, and other factors to adjust driver and traffic mix
characteristics. In Step 7, the top 20 intersections should then be ranked by the LOS
determined in Step 6.
The level-of-service calculations will provide an overall rating for the intersection in
terms of a letter classification from A (the least delay and best operating) to F (the most delay
and worst congestion and operation). Intersections that are calculated with a current or future
level-of-service of A, B, or C (Step 8) need not be considered further because they do not have
sufficient traffic volumes and delay to require further review (Step 9). For those intersections
with a level-of-service D, E, or F, however, additional analysis (Step 10) is required to
determine if these congested intersections should be reviewed further for air quality impacts.
The remaining part of this procedure is to analyze the three highest LOS ranked intersections
(Step 11) using the CAL3QHC model. Similarly, in Step 12, the three highest traffic ranked
intersections should be modeled using the CAL3QHC model. An example of the procedures
discussed in this section for ranking intersections is given in Section 5 of this report.
4-5
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4.6 Individual Intersection Analysis (Steps 13 through 18)
When the multiple intersection screening using the traffic and LOS ranking (Steps 1
through 12) results in one or more intersections requiring further analysis, or when an
individual intersection or group of intersections is being considered, the procedures in Steps 13
through 18 should be followed. This guidance is divided into two main components:
1) Steps 13 through 15: Assembling all required data including roadway geometry
and receptor locations.
2) Steps 16 through 18: Applying the CAL3QHC model to calculate 1-hour and 8-
hour concentrations for comparison with the NAAQS.
In a typical evaluation, the individual intersection or group of three highest ranked
intersections based on traffic and LOS (from Steps 1 through 12) would be modeled to
calculate 1-hour and 8-hour concentrations for comparison with the NAAQS. When all
intersections of interest have been modeled, the analysis may stop. The next step is to mitigate
the violating intersections through lane reconfiguration, signal timing, traffic diversion, exclu-
sive vehicle allowances per lane, or other techniques and then to rerun the analysis for the
adjusted scenarios.
4.7 Input Data Selection
The remainder of Section 4 provides specific guidance regarding individual inputs for
the modeling of an intersection. The calculation of emissions from the movement and delay of
vehicular traffic and air quality impacts through dispersion modeling requires specifying
particular inputs describing the site geometry, signalization, and ambient meteorological
conditions.
4-6
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4.7.1 Ambient Conditions
Meteorological conditions must be specified for both emission estimates and dispersion
modeling. Ambient temperature is required for input to the latest version of the MOBILE
emission factor model (hereafter referred to as MOBILE). Wind speed, wind direction,
atmospheric stability class, mixing height, and surface roughness are required for input to the
CAL3QHC dispersion model.
Temperature
The temperature corresponding to each of the ten highest non-overlapping 8-hour CO
monitoring values for the last three years should be obtained. The average 8-hour temperature
for each event should be calculated and then all ten values should be averaged for use with
MOBILE. The ten highest concentrations and the dates of their occurrence are available in the
Aerometric Information Retrieval System (AIRS) from EPA's National Air Data Branch. For
most major U.S. cities, these temperatures are available in the Local Climatological Data
Summaries published by the U.S. Department of Commerce or from any airport meteorological
station. As a simple alternative, the average temperature in January may be used instead of the
above approach for determining temperature input to the latest version of the MOBILE
emission factor model. When urban areawide modeling utilizing the Urban Airshed Model
(UAM) is being used in conjunction with the CAL3QHC intersection model, each hour
modeled in the UAM simulation should be modeled with CAL3QHC using the hourly
temperature from the UAM grid square where the intersection is located.
Wind Soeed
A worst-case wind speed of 1.0 m/s should be used in the CAL3QHC model for all
analyses, except.when urban areawide modeling using the Urban Airshed Model (UAM) is
being performed in conjunction with the CAL3QHC intersection model. In such cases, each
hour modeled in the UAM simulation should be modeled with CAL3QHC using the hourly
wind speed from the UAM grid square where the intersection is located.
4-7
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Wind Direction
For the applications of CAL3QHC, every 10° of wind direction from 0 to 350° (or a
total of 36 directions) should be used, except when urban areawide modeling using the Urban
Airshed Model (UAM) is being performed in conjunction with the CAL3QHC intersection
model. In such cases, each hour modeled in the UAM simulation should be modeled with
CAL3QHC using the hourly wind direction from the UAM grid square where the intersection
is located.
Atmospheric Stability Class
The atmospheric stability class that should be used for intersection analyses varies by
the urban/rural nature of the area surrounding the intersection. The following recommended
stability classes should be used for the area of interest.
Area Stability Class
Urban D (4)
Rural E (5)
If the land use classification technique of Auer (1978) indicates more than half of the area to
be rural, the use of E stability is recommended. If the land use classification technique of
Auer shows more than half of the area to be urban, the use of D stability is recommended.
Mixing Heights
A mixing height of 1000 m should be used for all 1-hour and 8-hour estimates. The
CAL3QHC model, as with most mobile source models, is not sensitive to mixing height
because the ambient impacts are very close to near ground-level sources.
Surface Roughness
Surface roughness (zj should be selected from the guidance provided in the CALINE3
manual. Table 4-1 which is reprinted from the CALINE3 manual provides the recommended
4-8
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values for z0 for various land uses. Some recommended values are 321 cm for a central
business district area, 175 cm for an office area, and 108 cm for a suburban area.
4-9
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TABLE 4-1
SURFACE ROUGHNESS LENGTHS (z,,) FOR VARIOUS LAND USES
Type of Surface
Smooth desert
Grass (5-6 cm)
Grass (4 cm)
Alfalfa (15.2 cm)
Grass (60-70 cm)
Wheat (60 cm)
Corn (220 cm)
Citrus orchard
Fir forest
City land-use
Single family residential
Apartment residential
Office
Central business district
Park
z0 (cm)
0.03
0.75
0.14
2.72
11.40
22.00
74.00
198.00
283.00
108.00
370.00
175.00
321.00
127.00
4-10
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4.7.2 Estimating 8-Hour Concentrations from 1-Hour Concentrations
The calculation of 8-hour concentration estimates from 1-hour concentration estimates
is a technique that has been used since the initial distribution of Volume 9 in 1975. The
primary focus in this calculation is on the relationship between 1-hour and 8-hour traffic
volumes and meteorological conditions. Because the ratio of the 8-hour to 1-hour
concentration estimate (persistence factor) represents a combination of the variability in both
traffic and meteorological conditions, the ratio of measured monitored concentrations should be
used to determine the persistence factor, since monitoring data include the effects of variability
in both traffic and meteorological conditions.
The following specifications for the use of a persistence factor to estimate 8-hour
concentrations from predicted maximum 1-hour CO concentrations are for application to the
intersection techniques described in this document. The preferred method is to use monitoring
data. The persistence factor should be based on values obtained using the ratio of the 8-hour
to the maximum 1-hour measured CO concentration within the 8-hour period. This persistence
factor should be calculated for each of the 10 highest non-overlapping 8-hour concentrations
obtained from the latest three CO seasons of monitoring data and averaged. A CO season is
generally defined as the period from October through April, but it may be longer or shorter in
some areas of the country. If less than three CO seasons are not available then the use of one
or two seasons of data would be allowed. If monitoring data are not available at all or there
are less than 3 months of one CO season of data available, then use a 0.7 default factor to
convert from a peak 1-hour concentration to a peak 8-hour concentration. The 0.7 factor is a
reasonably conservative persistence factor based on studies of monitoring data throughout
many regions of the country. Thus, EPA recommends the use of a 0.7 persistence factor in a
local area where monitoring data are not available. If a persistence factor other than 0.7 is
obtained through the use of monitored data in a local area, it should be used rather than 0.7.
4-11
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4.7.3 Background Concentrations
Total CO concentrations are a combination of the intersection of interest and
background concentrations due to other local sources (i.e., more distant roadways and parking
lots or industrial sources). The contributions from other sources may be determined from
monitoring data or urban areawide modeling.
For the purposes of this guidance, two levels of background determination are rec-
ommended on the basis of the study type.
1) State Implementation Plan (SIP)
For SIP analysis, urban area modeling using UAM or RAM should be used in
conjunction with both current and projected (future) CO emission inventories to
estimate background. The UAM or RAM CO concentration in the grid square
where the intersection is located should be used for background.
2) Project Analysis
For new construction or a project level analysis, background concentrations
should be determined using local monitoring data. The background
concentration should be obtained from a representative background monitoring
site not affected by the intersection of interest. Background monitored data
should be adjusted for the future. This can be accomplished by multiplying the
present CO background by the ratio of the future MOBILE CO emission factor
to the current MOBILE CO emission factor and multiplying by the ratio of
future to current traffic. If representative background monitoring data are not
available, the EPA Regional Office should be contacted regarding the use of
default background concentrations.
4.7.4 Other Input Data
Additional CAL3QHC required inputs are specified in this section to guide the user in
the analysis of the air quality impact at an intersection.
Link length
On either side of the intersection, the length of the free-flow link should be the center-
to-center distance from the intersection of interest to the next intersection. A maximum of
300 m for this distance is sufficient, but the user may specify a longer distance for complete-
4-12
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ness. The queue link should originate at the approach stop line and extend to the end of the
queue.
Link Width
As in the CALINE3 model, 3 m should be added to either side of each free-flow link.
For the queue links, no additional width should be added. The additional width is added to the
free-flow links to account for the added mechanical turbulence caused by the moving vehicles.
Receptors
Receptors for the modeling should be located on each side of approach and departure
links. The receptors should be located at least 3 m from the edge of each of the traveled
roadways which converge at the intersection and where the general public has access (see
Section 2). At a minimum, receptors should be located near the corner and at mid-block for
each approach and departure at the intersection. Receptors should be placed on both sides of
the roadways. In the case of long approaches, it is recommended that receptors be placed at
25 and 50 m from the intersection corner. More receptors can be located where desired by the
user. The receptors should be placed vertically at 1.8 m above the ground.
Source Height
The source height should be specified as 0.0 m.
Hot/Cold Starts
Vehicular emissions are greatly affected by vehicular speed, ambient temperature,
thermal state of the engine, vehicle age and mileage distribution, inspection and maintenance
programs, and fuel volatility and other local requirements. It is recommended that most of
these variables be as representative as possible for the analysis area rather than the default
MOBILE values. One of the parameters that has the greatest effect on emissions is the
percentage of vehicles that are in the cold start and hot start mode. In areas where the local
air quality agency has compiled localized cold and hot start percentages, these measured values
should be used. For areas that lack localized data, the use of Federal Test Procedure (FTP)
conditions (20.6 percent cold start, 27.3 percent hot start) may be used as input to MOBILE.
4-13
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Variations from these values may be required if conditions are different Examples include
traffic due to a parking lot at a place of employment (high number of cold starts) or a rural or
suburban intersection with little nearby parking (high number of stabilized conditions).
Extreme examples would include traffic exiting from a park and ride lot where there would be
100 percent cold starts or traffic exiting from a large tunnel where there would be 100 percent
hot stabilized conditions.
Vehicle Speed
Vehicle speed should typically be less than the posted speeds. Congestion at the
intersection can cause vehicle free-flow speeds to be less than posted or design speeds. It is
recommended that the vehicle speed on the link be obtained from traffic engineers familiar
with the area under consideration. The vehicle speed for a free-flow link represents the speed
experienced by drivers travelling along the link in the absence of the delay caused by the
intersection traffic signal. In the absence of recommended information from traffic engineers,
the user should use the techniques in Chapter 11 of the Highway Capacity Manual (HCM)
(TRB, 1985) to estimate free-flow vehicle speed. The free-flow speeds for arterials as
recommended by the HCM are given in Table 4-2. The criteria for the classification of
arterials for use in conjunction with the free-flow speeds given in Table 4-2 are presented in
Table 4-3. Definitions of suburban, urban, and intermediate are contained in Chapter 11 of the
Highway Capacity Manual (TRB, 1985). Considerable caution should be exercised in using
these speeds since they represent the traffic operating environment with minimal to moderate
pedestrian/parking frictions. In urban areas with significant pedestrian conflicts and/or parking
activities (e.g., Central Business Districts, Fringe Business Districts), the use of substantially
lower free-flow speeds (e.g., 15 to 20 mph) may be warranted.
4-14
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TABLE 4-2
FREE FLOW SPEEDS FOR ARTERIALS (SOURCE: TRB, 1985)
Arterial Class I II III
Range of free flow
speeds (mph) 35 to 45 30 to 35 25 to 30
Typical free flow
speeds (mph) 40 33 27
4-15
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TABLE 4-3
ARTERIAL CLASS ACCORDING TO FUNCTION AND DESIGN CATEGORY
(SOURCE: TRB, 1985)
Design Category
Principal
Arterial
Minor
Arterial
Suburban
Intermediate
(Suburban/Urban)
Urban
I
n
III
n
ni
m
4-16
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SECTION 5
EXAMPLES
Two examples are presented in this section in order to describe the modeling procedures
for a SIP attainment demonstration for the year 1995 and a project level analysis for the same
year.
5.1 Example of a SIP Attainment Demonstration
Monitoring data for a single central business district monitoring site have indicated that
the area is nonattainment for CO. To determine the extent of this nonattainment area and the
need for mitigative measures for the current and future CO levels, a modeling analysis was
conducted. The local planning agency has prepared average daily traffic (ADT) maps to assist
in identifying major roadway corridors and intersections. An inventory of other sources of CO
emissions in the area has also been prepared. This areawide inventory was used with the Urban
Airshed Model (UAM) and nearby representative hourly meteorological data to model the
current urban areawide background concentration of CO. The projected future emissions
inventory was then used in the UAM with the same hourly meteorological data to estimate
future urban areawide background concentration. These background or areawide concentrations
were later added to the local source impacts from individual intersections.
A qualitative and quantitative description of the traffic and physical characteristics in the
vicinity of the nonattainment area were compiled. The project related narrative with respect to
the modeled intersections including diagrams were included in the final analysis report. The air
quality objectives were analyzed in order to determine the level of analysis, the resources, and
the amount of effort required to determine whether CO attainment will be reached in 19.95 as
5-1
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required under the Clean Air Act Amendments of 1990. All the data required to determine the
traffic, level-of-service, emissions, and air quality impacts were assembled. A scaled map of the
nonattainment area including all intersections with approaches/ departures identified was
obtained. The characteristics of each link including the number of lanes, road width, turning
channels, type of intersection control, and signal timing were compiled. Also the through,
turning, and total traffic volumes along with vehicle speeds for each link during average peak
hourly traffic were obtained. Hourly UAM meteorological data for temperature, wind speed,
and wind direction were compiled for input to the CAL3QHC intersection model. A land use
analysis using the Auer (1978) land use technique was performed and the results indicated that
more than 50% of the area is classified as urban. Thus, stability class D was used for the
intersection modeling. Thus, stability class D was used for the intersection modeling. The
default mixing height of 1000 meters was also used in CAL3QHC.
For this analysis, the first level in determining CO impacts from multiple locations
involved the use of the ADT maps of the area to identify the major vehicular corridors. Any
crossings of these major corridors were determined to be locations where air impacts could be
consequential, especially if the location was also a signalized intersection. Nonsignalized
intersections were not considered further. The results of this data gathering left 35 signalized
intersection sites for further analysis.
5.1.1 Ranking by Volume and LOS
The 35 intersections were ranked by traffic volume and the top 20 intersections were
identified. The top 20 intersections ranked by traffic volume are as follows:
Location No. of vehicles/day
Main St. at Local St. 27,600
4th St. at Pine St. 26,286
Wood Ave. at Hurricane Ave. 24,708
Main St. at Pike Ave. 24,144
Vince Ave. at Robert Rd. 23,064
Conley St. at Mary St. 20,922
Town St. at Dodge Ave. 20,704
Spruce St. at Pine St. 19,980
3rd St. at Miami St. 18,306
5-2
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2nd Ave. at Main St. 17,226
1st Ave. at Pine St. 16,970
Bull Run Rd. at Lard St. 16,142
Winn St. at Simpson Rd 14,644
Concord Ave. at Main St. 14,020
Lantern Lane at Fuller St. 13,645
Thoreau St. at Wood Ave. 13,600
Baker Ave. at Emerson Rd. 13,500
Twister Lane at Hawthorne St. 13,400
Academy Drive at Main St. 13,300
Front St. at Commercial St. 13,100
For the top 20 intersections ranked above for traffic volumes, the level-of-service
(LOS) was calculated for each intersection. A computerized version of Chapter 9 of the
1985 Highway Capacity Manual (TRB, 1985) was used to calculate the LOS. The LOS is
calculated using the number of lanes, lane width, red time, green time, total cycle time,
approach speed, lane capacity, turning movement, and other factors to adjust driver and
traffic mix characteristics. The computerized software also provided the capacity of
saturated flows of each link which were later used in the dispersion modeling analysis. The
top 20 intersections identified above were then ranked by the LOS for each intersection as
follows:
Location LOS
Main St. at Local St. F
4th St. at Pine St. F
Main St. at Pike Ave. F
Vince Ave. at Robert Rd. F
Conley St. at Mary St. F -
Town St. at Dodge Ave. F
1st Ave. at Pine St. F
Winn St. at Simpson Rd F
Lantern Lane at Fuller St. F
Wood Ave. at Hurricane Ave. E
Spruce St. at Pine St. E
2nd Ave. at Main St. E
Bull Run Rd. at Lard St. E
Concord Ave. at Main St. E
Twister Lane at Hawthorne St. E
3rd St. at Miami St. D
5-3
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Thoreau St. at Wood Ave. D
Baker Ave. at Emerson Rd. D
Academy Drive at Main St. C
Front St. at Commercial St. B
The intersections with the same LOS are ranked by the degree of delay associated
with each intersection. The top three intersections ranked by traffic volume are as follows:
Main St. at Local St.
4th St. at Pine St.
Wood Ave at Hurricane Ave.
The top three intersections ranked by LOS are as follows:
Main St. at Local St.
4th St. at Pine St.
Main St. at Pike Ave.
Two of the intersections are found in both groups, thus the intersection modeling analysis
will be performed for the following four intersections:
Main St. at Local St.
4th St. at Pine St.
Wood Ave at Hurricane Ave.
Main St. at Pike Ave.
Detailed model input and output data for the first intersection (Main St. at Local St.) are
given in the following sections.
5.1.2 Emissions Modeling
The local air quality agency has compiled localized cold and hot start percentages,
which were used as input to MOBILE. -The hourly temperature data used in the UAM
analysis were used with MOBILE. Also the local recommended values for the
Inspection/Maintenance (I/M) and Anti-tampering (ATP) program specifications were used.
No local data were available for the VMT mix or annual mileage accumulation rates by age
or registration distributions, so MOBILE defaults were used. The base Reid Vapor Pressure
(RVP) is assumed to be 9.0 psi and the calendar year is 1995. For the Main St. at Local St.
intersection, the free-flow speed of each approach and departure link, as determined by
traffic engineers, was 20 mph. The MOBILE input file is shown in Figure 5-1 and the
5-4
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corresponding MOBILE output is shown in Figure 5-2. From the output file, the free-flow
(at 20 mph) and queue link emission rates arc obtained (17.2 g/mi for the free flow and
259.1 g/hr for the idle or queue). The emission rates are then used as input to the
CAL3QHC dispersion model.
5-5
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1
MOBILE - Main St. at Local St.
1
1
1
1
1
2
1
2
1
1
2
4
2
2
1
1
82 30 60 20 0. 0. 75. 3 1 2222 1 11
84 60 20 2222 21 75.0 22112121
1 95 20.0 55.0 18.9 25.3 18.9
C55.0 55.0 9.0 9.0 95
Figure 5-1. MOBILE input file used in the example.
5-6
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MOBILE - Main St. at Local St.
MOBILE4.1(4Nov91)
-M120 Warning:
+ MOBILE4.1 does not model most 1993 and later Clean Air Act
requirements; Emission Factors for CY 1993 or later are affected.
I/M program selected:
Start year (January 1):
Pre-1981 MYR stringency rate:
First model year covered:
Last model year covered:
Waiver rate (pre-1981):
Waiver rate (1981 and newer):
Compliance Rate:
Inspection type:
Inspection frequency
Vehicle types covered:
1981 & later MYR test type:
Anti-tampering program selected:
Start year (January 1):
First model year covered:
Last model year covered:
Vehicle types covered:
Type:
Frequency:
Compliance Rate:
Air pump system disablements:
Catalyst removals:
Fuel inlet restrictor disablements
Tailpipe lead deposit test:
EGR disablement:
Evaporative system disablements:
PCV system disablements:
Missing gas caps:
1982
30%
1960
2020
0.%
0.%
75.%
Manual
Annual
LDGV -
LDGT1 -
LDGT2 -
HDGV -
Idle
1984
1960
2020
LDGV , LDGT1,
Decentralized
Annual
75.0%
Yes
Yes
: No
No
Yes
No
Yes
No
decentralized
Yes
Yes
Yes
Yes
LDGT2, HDGV
Total HC emission factors include evaporative HC emission factors.
Cal. Year: 1995
Region: Low
I/M Program: Yes
Anti-tarn. Program: Yes
Altitude:
Ambient Temp:
Operating Mode:
500. Ft.
55.0 (F)
18.9 / 25.3 / 18.9
Veh. Type: LDGV
Minimum Temp: 55. (F) Maximum Temp: 55. (F)
Period 1 RVP: 9.0 Period 2 RVP: 9.0 Period 2 Yr: 1995
LDGT1 LDGT2 LDGT HDGV LDDV LDDT HDDV MC All Veh
Veh. Spd.: 20.0 20.0
VMT Mix: 0.602 0.189 0.078
Composite Emission Factors (Gm/Mile)
Exhst CO: 15.17 17.92 21.40 18.94 53.96
Hot Stabilized Idle Emission Factors (Gm/Hr)
Idle C0:260.97 301.23 366.89 320.43 299.54
0.035 0.004 0.001 0.084
20.(
0.007
1.66 1.85 11.47 23.72 17.21
22.57 33.61 50.52 230.61 259.09
Figure 5-2. MOBILE output file for the input file listed in Figure 5-1.
5-7
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5.13 Dispersion Modeling
The intersection at Main St. and Local St. is located in the suburban portion of the
city near many small office complexes. The recommended surface roughness length for this
type of land use is 175 cm (see Table 4-1). The Main St. and Local St. intersection is
characterized by Main St., a four-lane, two-way street running north-south with average
daily traffic of about 18,400 vehicles and a peak-hour volume of 1,500 vehicles in each
direction. The cross-street (Local St.) is a one-way street toward the east with an average
daily traffic volume of 9,200 vehicles and a peak-hour volume of 800 vehicles. Figure 5-3
shows the geometry of the intersection, including the coordinate endpoints of each link, the
model assumed roadway widths, and the receptor locations.
The criteria presented in Section 2 were used in the selection of the receptor loca-
tions. Receptors were located on both sides of the street. The receptors were located near
the sidewalk center, 3 m (10 ft) from the nearest lane edge at a height of 1.8 m (6 ft).
Receptors were located at the corner, along with 25 and 50 m from the corner because the
midblock distance was greater than 50 m.
All site geometry, land and receptor coordinates and configurations, traffic volume
for the peak hour, and meteorological data were used to compile the CAL3QHC input file
shown in Figure 5-4. The intersection modeling analysis results will be combined with
UAM results for this SIP analysis. Therefore, the hourly temperature, wind speed, and
wind direction from the UAM grid square where the intersection is located were also used
in the CAL3QHC model. The UAM concentration from the grid square where the
intersection is located was input to the CAL3QHC model as the background concentration
to determine the total impact for each hour. The results were then averaged over 8 hours to
determine the maximum 8-hour concentration. The CAL3QHC output file for one hour
where the UAM background concentration is 3 ppm is shown in Figure 5-5.
5-8
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C-10,10003 cio,iooco
N
C-aq.1743
C-30,323
C-184,2
0X
C- 102, 203
B
o
C-10. 103
C-20,(jr
• • •
C-102.-20D C-30--203
C- 30,-823
•
C-3O.-1743
• RECEPTORS
O LIN< COORDINATES
ALL CCX3RDINATES IN FEET
NOT TO SCALE
C30.1743
C30.9ZD
•
•C1B4, 203
LOCAL STREET
C1O,-103STOP LINE POINT
20' __
C1000. 03
C 102^-203
•
C 30,-1743
Figure 5-3. Geometric layout of Main St. and Local St. for example
intersection.
5-9
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Main Street at Local Street
60.175.
0.
0.20
.3048
REG 1
REC 2
REC 3
REC 4
REC 5
REC 6
REC 7
REC 8
REC 9
REC 10
REC 11
REC 12
REC 13
REC 14
REC 15
REC 16
REC 17
REC 18
REC 19
REC 20
MAIN ST. AND LOCAL ST.
1
Main St.NB Appr. AG
2
Main St.NB Queue AG
90 40
1
Main St.NB Dep. AG
1
Main St. SB Appr. AG
2
Main St. SB Queue AG
90 40
1
Main St. SB Dep. AG
1
Local St. Appr. AG
2
Local St. Queue AG
90 50
30.
102.
184.
30.
102.
184 .
30.
30.
-30.
-30.
-30.
-102.
-184.
-30.
-102.
-184.
-30.
-30.
30.
30.
20.
20.
20.
-20.
-20.
-20.
-92.
-174.
-20.
-92.
-174.
-20.
-20.
20.
20.
20.
92.
174.
92.
174.
INTERSECTION
10.
. 10.
3.0
10.
-10.
-10.
3.0
-10.
0.
-20.
3.0
-1000
-10
1500
0
0
10
1500
0
0
- 0
800
10
10
259.1
10
-10
-10
259. 1
-10
. -1000
. -1000
259.1
6.
6.
6.
6.
6.
6.
6.
6.
6.
6.
6.
6.
6.
6.
6.
6.
6.
6.
6.
6.
910
0. 1500.17.2 0. 40.
. -1000. 0. 20. 2
1700 2 1
. 1000. 1500.17.2 0. 40.
. 1000. 1500.17.2 0. 40.
1000. 0. 20. 2
1800 2 1
. -1000. " 1500.17.2 0. 40.
0. 800.17.2 0. 40.
0. 0. 20. 2
1400 2 3
Local St. Dep. AG
2. 10.4 1000. 3.ON
0.
0. 1000.
0.
800.17.2 0. 40.
Figure 5-4. The CAL3QHC model input file used for the SIP attainment example.
5-10
-------
CAL3QHC: LINE SOURCE DISPERSION MODEL - VERSION 2.0, JANUARY 1992
JOB: Main Street at Local Street
DATE: 11/10/92 TIME: 13:33
RUM: MAIN ST. AND LOCAL ST. INTERSECTION
SITE < METEOROLOGICAL VARIABLES
VS - 0.0 CM/S VD - 0.
U - 2.0 M/S CLAS -
LINK VARIABLES
LINK DESCRIPTION
1. Main St. KB Appr.
2. Main St.NB Queue
3. Main St.NB Dep.
4. Main St. SB Appr.
5. Main St. SB Queue
6. Main St. SB Dep.
7 . Local St . Appr .
8. Local St. Queue
0 CM/S
4 (D)
zo
ATIM
- ns.
- 60.
CM
MINUTES MIXH -
LINK COORDINATES (FT)
XI
10
10
10
-10
-10
-10
0
-20
9. Local St. Dep. 0
Yl
.0 -1000
.0 -10
.0 0
.0 0
.0 10
.0 0
.0 0
.0 0
.0 0
0
0
0
0
0
0
0
0
0
X2
10.0
10.0
10.0
-10.0
-10.0
-10.0
-1000.0
-129.4
1000.0
Y2
0.0
-221.3
1000.0
1000.0
199.3
-1000.0
0.0
0.0
LENGTH
(FT)
1000.
211.
1000.
1000.
189.
1000.
1000.
109.
0.0 1000.
1000. M
BRG TYPE
(DEC)
360. AG
180. AG
360. AC
360. AG
360. AG
180. AG
270. AG
270. AG
90. AC
AMB -
VPH
1500
618
1500
1500
618
1500
800
772
800
3.0 PPM
EF
(G/MI)
17.2
100.0
17.2
17.2
100.0
17.2
17.2
100.0
17.2
BRG - 10.
H H
(FT) (FT)
0.0 40.0
0.0 20.0 0
0.0 40.0
0.0 40.0
0.0 20.0 0
0.0 40.0
0.0 40.0
0.0 20.0 0
0.0 40.0
DEGREES
V/C QUEUE
(VEH)
88 10.7
83 9.6
74 5.6
Figure 5-5. The CAL3QHC model output file for the SIP attainment example.
5-11
-------
PAGE 2
JOB: Main street at Local Street
DATE: 11/10/92 TIME: 13:33
ADDITIONAL QUEUE LINK PARAMETERS
RUN: MAIN ST. AND LOCAL ST. INTERSECTION
LINK DESCRIPTION
2. Main st.NB Queue
5. Main St. SB Queue
8 . Local St . Queue
RECEPTOR LOCATIONS
RECEPTOR
1. REC 1
2. REC 2
3. REC 3
4. REC 4
5. REC 5
6. REC 6
7. REC 1
8. REC 8
9. REC 9
10. REC 10
11. REC 11
12. REC 12
13. REC 13
14. REC 14
15. REC 15
16. REC 16
17. REC 17
18. REC 18
19. REC 19
20. REC 20
CYCLE
LENGTH
(SEC)
90
90
90
X
30
102
184
30
102
184
30
30
-30
-30
-30
-102
-184
-30
-102
-184
-30
-30
30
30
RED CLEARANCE
TIME LOST TIME
(SEC) (SEC)
40 3.0
40 3.0
50 3.0
COORDINATES (FT)
1 Z
.0 20.0
.0 20.0
.0 20.0
.0 -20.0
.0 -20.0
.0 -20.0
.0 -92.0
.0 -174.0
.0 -20.0
.0 -92.0
.0 -174.0
. 0 -20.0
.0 -20.0
.0 20.0
.0 20.0
.0 20.0
.0 92.0
.0 174.0
. 0 92 . 0
.0 174.0
APPROACH SATURATION IDLE SIGNAL ARRIVAL
VOL FLC* RATE EM FAC TYPE RATE
(VPH) (VPH) (qm/hrl
1500 1700 259.10 2 1
1500 1800 259.10 2 1
800 1400 259.10 2 3
6.0
6.0
6.0
6.0
6.0
6.0
6.0
6.0
6.0
6.0
6.0
6.0
6.0
6.0
6.0
6.0
6.0
6.0
6.0
6.0
MODEL RESULTS
REMARKS : In search of the angle corresponding to
the maximum concentration, only the first
angle, of the angles with same maximum
concentrations, is indicated as maximum.
HIND
ANGLE
(DEGR)
10.
CONCENTRATION
(PPM)
REC1 REC2 REC3 REC4 REC5 REC6 REC7 REC8 REC9 REC10 REC11 REC12 REC13 REC14 REC15 REC16 REC17 REC18 REC19 REC20
THE HIGHEST CONCENTRATION IS 6.40 PPM AT 10 DEGREES FROM REC9 .
THE 2ND HIGHEST CONCENTRATION IS 5.40 PPM AT 10 DEGREES FROM REC14.
THE 3RD HIGHEST CONCENTRATION IS 5.20 PPM AT 10 DEGREES FROM REC10.
Figure 5-5. Continued.
5-12
-------
The maximum 1-hour UAM plus CAL3QHC modeled concentration was 6.4 ppm
and the maximum 8-hour concentration was 4.0 ppm. The highest modeled CO
concentrations for both the 1-hour and 8-hour averaging periods are less than the NAAQS,
so further analysis of this intersection is not required. The modeling analysis was then
conducted for the remaining three intersections discussed in Section 5.1.2.
5.2 Example of a Project Level Analysis
The same intersection example presented in Section 5.1 is used to demonstrate a
project level analysis. The temperature corresponding to the ten highest non-overlapping 8-
hour CO monitoring values for the last three years were obtained from nearby,
representative monitors. The average 8-hour temperature for each of the ten highest events
was calculated and then averaged over all ten events for use with MOBILE. For a project
level analysis, the default meteorological data of a 1 m/s wind speed, every 10° of wind
direction from 0 to 350°, and 1000 m mixing height were used as input to the CAL3QHC
model. Since the project was located in an urban area, the neutral (D) stability class was
also input to CAL3QHC. The 1-hour background concentration was obtained from a
representative background monitoring site not affected by the Main St. and Local St.
intersection. The 1-hour background concentration of 2.7 ppm was input to the CAL3QHC
model. The CAL3QHC input file is shown in Figure 5-6 and the CAL3QHC output file
associated with this project level analysis is presented in Figure 5-7.
The three most recent CO seasons (October through April) of monitoring data were
used to calculate a persistence factor to convert from 1-hour to 8-hour concentrations. The
persistence factor was calculated using the 10-highest non-overlapping 8-hour concentrations
and the highest 1-hour concentration in each 8-hour period. The average of the ratios of the'
ten 8-hour to 1-hour values was determined to be 0.65. As shown in Figure 5-7, the
maximum 1-hour concentration for this intersection is 9.1 ppm and the maximum 8-hour
concentration is calculated to be 5.9 ppm using the 0.65 persistence factor.
5-13
-------
Main Street at Local
REC 1
REC 2
REC 3
REC 4
REC 5
REC 6
REC 7
REC 8
REC 9
REC 10
REC 11
REC 12
REC 13
REC 14
REC 15
REC 16
REC 17
REC 18
REC 19
REC 20
Street
30.
102.
184.
30.
102.
184.
30.
30.
-30.
-30.
-30.
-102.
-184.
-30.
-102.
-184 .
-30.
-30.
30.
30.
20.
20.
20.
-20.
-20.
-20.
-92.
-174.
-20.
-92.
-174.
-20.
-20.
20.
20.
20.
92.
174.
92.
174.
MAIN ST. AND LOCAL ST. INTERSECTION
1
Main St.NB Appr .
2
Main St.NB Queue
90 40
AG 10. -1000
AG 10. -10
3.0 1500
.
f
259.
60.175.
6.
6.
6.
6.
6.
6.
6.
6.
6.
6.
6.
6.
6.
6.
6.
6.
6.
6.
6.
6.
910
10. 0.
10. -1000.
1 1700 2
0.20
.3048
Main St.
1
Main St.
2
Main St.
Main St.
1
Local St
2
Local St
1
NB Dep.
SB Appr.
SB Queue
90
SB Dep.
. Appr.
. Queue
90
40
50
AG
AG
AG
0
AG
AG
AG
3
AG
Local St. Dep.
1. 0.4 1000. 2.7Y 10
10. 0.
-10. 0.
-10. 10.
3.0 1500
10.
-10.
1000.
1000.
-10.
0.
-20. 0.
3.0 800
0. 0.
0 36
-10. 1000.
259.1 1800 2 1
-10. -1000.
-1000. 0.
-1000. 0.
259.1 1400 2 3
1000.
0.
1500.17.2
0. 20.
0. 40.
2
1500.17.2 0. 40.
1500.17.2 0. 40.
0. 20. 2
1500.17.2 0. 40.
800.17.2 0. 40.
0. 20. 2
800.17.2 0. 40.
Figure 5-6. The CAL3QHC model input file used for the project level example.
5-14
-------
CAL3QHC: LINE SOURCE DISPERSION MODEL - VERSION 2.0, JANUARY 1992
JOB: Main Street at Local Street
DATE: 11/10/92 TIME: 13:39
RUN: MAIN ST. AND LOCAL ST. INTERSECTION
SITE t METEOROLOGICAL VARIABLES
VS - 0.0 CM/S VD - 0.0
U - 1.0 M/S CLAS - 4
LINK VARIABLES
LINK DESCRIPTION
1. Main St. KB Appr.
2. Main St.NB Queue
3. Main St.NB Dep.
4. Main St. SB Appr.
5. Main St. SB Queue
6. Main St. SB Dep.
7. Local St. Appr.
8 . Local St . Queue
9. Local St. Dep.
XI
10.
10.
10.
-10.
-10.
-10.
0.
-20.
0.
CM/S 20 - 175.
(Dl ATIM - 60.
LINK COORDINATES (FT)
Yl X2
0 -1000
0 -10
0 0
0 0
0 10
o a
0 0
0 0
0 0
0 10.0
0 10.0
0 10.0
0 -10.0
0 -10.0
0 -10.0
0 -1000.0
0 -129.4
0 1000.0
CM
MIHUTES
Y2
0.0
-221.3
1000.0
1000.0
199.3
-1000.0
0.0
0.0
0.0
MIXH - 1000. M
LENGTH BRG
(FT) (DEG)
1000.
211.
1000.
1000.
189.
1000.
1000.
109.
1000.
360.
180.
360.
360.
360.
180.
270.
270.
90.
AMB
TYPE
AG
AG
AG
AG
AG
AG
AG
AG
AG
- 2
VPH
1500.
618.
1500.
1500.
618.
1500.
800.
772.
800.
7 PPM
EF
(G/MI)
17.2
100.0
17.2
17.2
100.0
17.2
17.2
100.0
17.2
H H
(FT) (FT)
0.0 40.0
0.0 20.0 0
0.0 40.0
0.0 40.0
0.0 20.0 0
0.0 40.0
0.0 40.0
0.0 20.0 0
0.0 40.0
V/C QUEUE
(VEH)
88 10.7
83 9.6
74 5.6
Figure 5-7. The CAL3QHC model output file for the project level example.
5-15
-------
JOB: Main Street at Local Street
DATE: 11/10/92 TIME: 13:39
ADDITIONAL QUEUE LINK PARAMETERS
RUN: MAIN ST. AND LOCAL ST. INTERSECTION
LINK DESCRIPTION
2. Main St.NB Queue
5. Main St. SB Queue
8 . Local St . Queue
RECEPTOR LOCATIONS
RECEPTOR
1. REC 1
2. REC 2
3. REC 3
4. REC 4
5. REC 5
6. REC 6
7. REC 7
8. REC 8
9. REC 9
10. REC 10
11. REC 11
12. REC 12
13. REC 13
14. REC 14
15. REC 15
16. REC 16
17. REC 17
18. REC 18
19. REC 19
20. REC 20
CYCLE
LENGTH
(SEC)
90
90
90
X
30
102
184
30
102
184
30
30
-30
-30
-30
-102
-184
-30
-102
-184
-30
-30
30
30
RED CLEARANCE
TIME LOST TIME
(SEC) (SEC)
40 3.0
40 3.0
50 3.0
COORDINATES (FT)
Y Z
0 20.0
0 20.0
0 20.0
0 -20.0
0 -20.0
0 -20.0
0 -92.0
0 -174.0
0 -20.0
0 -92.0
0 -174.0
0 -20.0
0 -20.0
0 20.0
0 20.0
0 20.0
0 92.0
0 174.0
0 92.0
0 174.0
APPROACH SATURATION IDLE SIGNAL ARRIVAL
VOL FLOW RATE EM FAC TYPE RATE
(VPH) (VPH) (gm/hr)
1500 1700 259.10 2 1
1500 1800 259.10 2 1
BOO 1400 259.10 2 3
6.0
6.0
6.0
6.0
6.0
6.0
6.0
6.0
6.0
6.0
6.0
6.0
6.0
6.0
6.0
6.0
6.0
6.0
6.0
6.0
Figure 5-7. Continued.
5-16
-------
JOB: Main Street at Local Street
MODEL RESULTS
RUN: MAIN ST. AND LOCAL ST. INTERSECTION
REMARKS : In search of the angle corresponding to
the maximum concentration, only the first
angle, of the angle* with same maximum
concentrations, is indicated as maximum.
WIND ANGLE RANGE: 0.-360.
KIND
ANGLE
(DEGR)
0.
10.
20.
30.
40.
50.
60.
70.
80.
90.
100.
110.
120.
130.
140.
150.
160.
170.
180.
190.
200.
210.
220.
230.
240.
250.
260.
270.
280.
290.
300.
310.
320.
330.
340.
350.
360.
MAX
DEGR.
CONCENTRATION
(PPM)
REC1 REC2 REC3
5.1
2.9
2.9
3.6
3.5
3.4
3.3
3.2
3.3
3.7
7.2
6.4
5.9
5.9
6.2
6.7
7.0
5.6
5.5
5.8
6.0
6.0
190
2.7
2.9
3.5
3.3
3.2
3.2
3.1
4.8
4.7
4.7
4.8
5.0
5.3
4.3
4.1
4.0
260
2.
2.
3.
3.
3.
3.
3.
3.
3.
3.
7
5
3
2
2
1
0
1
2
5
6
6
4
260
REC4
3.
3.
2.
2.
2.
3.
7.
6.
6.
6.
6.
7.
6.
3
1
»
9
1
0
6
3
3
7
0
4
280
REC5
3.
3.
2.
2.
2.
4.
4.
4.
4.
4.
4.
4.
280
2
7
7
2
2
2
4
6
7
6
RECK
3.
3.
2.
2.
2.
3.
3.
3.
3.
2
1
7
7
7
4
6
7
8
1
2
0
270
REC7
3.0
2.7
2.8
2.9
3.2
6.9
6.6
6.3
5.9
5.8
6.8
7.5
340
REC8
2.9
2.7
2.8
3.1
6.3
6.3
6.2
5.8
5.8
6.4
7.1
340
REC9
7
5
5
6
2
2
2
3
3
6
5
.4
.6
.9
.3
.9
.d
.9
.0
.5
.0
.6
10
REC10
6
5
5
6
2
2
2
2
2
3
3
2
3
8
0
9
8
8
7
7
1
7
10
REC11
6.3
5.3
5.2
5.2
2.9
2.8
2.8
2.7
2.7
2.9
3.0
10
REC12
7.0
4.5
4.1
3.8
2.7
2.7
2.8
2.9
3.1
4.6
5.1
5.3
50
REC13
3.9
4.
3.5
3.2
2.7
2.7
2.8
2.9
3.1
3.4
3.2
3.2
80
REC14
7.
6.
6.
8.
5.
5
5.
5.
5
2
2
2
0
4
9
2
6
6
9
9
4
8
9
8
9
no
REC15
4
6
6
6
5
5
4
4
3
2
2
2
2
1
2
2
5
3
8
9
5
3
1
9
2
8
8
8
7
7
8
130
REC16
3
3
3
5
5
5
4
3
3
3
3
3
3
2
2
2
2
2
2
4
5
6
6
3
6
3
2
6
2
2
3
5
5
4
8
8
7
7
7
2.9
5.6
100
REC17
7.0
6.8
6.6
6.3
6.1
6.0
6.0
6.2
6.8
8.0
3.8
3.7
3.4
3.0
2.9
2.8
2.7
2.8
2.8
2.9
4.2
5.6
8.0
160
REC18
5.
5.
5.
5.
5.
5.
5.
6.
6.
7.
5.
3.
3.
3.
2.
2.
2.
2.
2.
2.
2.
2.
2.
3.
4.
7.
170
5
6
7
9
9
a
9
9
0
7
2
6
1
a
2
0
9
9
8
8
7
7
a
8
9
1
7
9
REC19
3.1
2.9
2.8
2.8
2.7
2.7
2.8
2.9
2.9
3.0
3.0
3.4
6.6
6.7
6.7
6.5
6.4
6.2
5.9
5.6
5.5
5.5
5.6
5.7
5.8
5.8
5.5
4.9
6.7
200
REC20
4.7
3.7
3.1
2.9
2.8
2.8
2.7
2.7
2.7
2.8
2.8
2.9
2.9
2.9
2.9
3.3
4.4
6.6
6.6
6.7
6.3
6.0
5.8
5.4
5.4
5.4
5.2
5.0
5.0
4.8
4.7
4.8
5.0
5.1
4.7
6.7
210
THE HIGHEST CONCENTRATION IS 9.10 PPM AT 10 DEGREES FROM REC9 .
THE 2ND HIGHEST CONCENTRATION IS 8.40 PPM AT 170 DEGREES FROM REC14.
THE 3RD HIGHEST CONCENTRATION IS 8.10 PPM AT 340 DEGREES FROM REC7 .
Figure 5-7. Continued.
5-17
-------
SECTION 6
REFERENCES
Auer, A., 1978. Correlation of Land Use and Cover with Meteorological Anomalies.
Journal of Appl. Met., 17, 636-643.
Benson, P., 1979. CALINE3 - A Versatile Dispersion Model for Predicting Air
Pollutants Levels Near Highways and Arterial Streets. Report No. FHW-A/CA/TL-
79/23. Office of Transportation Laboratory Sacramento, California.
Benson, P., 1989. CALINE4 - A Dispersion Model for Predicting Air Pollutant
Concentrations Near Roadways. Report No. FHWA/CA/Tl-84/15. Office of
Transportation Laboratory, Sacramento, CA.
Bullin, G., J. Korpics, and M. Hlavinka, 1990. User's Guide to the TEXIN2/MOBILE4
Model. Research Report 283-2. Texas State Department of Highways and Public
Transportation. College Station, TX.
EMI Consultants, 1985: The Georgia Intersection Model for Air Quality Analysis.
Knoxville, TN.
EPA, 1974. Automobile Exhaust Modal Analysis Model. EPA-460/3-74-005.
Ann Arbor, MI.
EPA, 1975a. Guidelines for Air Quality Maintenance Planning and Analysis, Volume 9:
Evaluating Indirect Sources. EPA-450/4-75-001. Research Triangle Park, NC.
EPA, 1975b. User's Guide for HIWAY: A Highway Air Pollution Model.
EPA-650/4-74-008. Research Triangle Park, NC.
EPA, 1978a. Carbon Monoxide Hot Spot Guidelines, Volume I - V. EPA-450/3-78-033
through EPA-450/3-78-037. Research Triangle Park, NC.
EPA, 1978b. Guidelines for Air Quality Maintenance Planning and Analysis, Volume 9
(Revised): Evaluating Indirect Sources. EPA-450/4-78-001. Research Triangle
Park, NC.
6-1
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EPA, 1980. User's Guide for HIWAY-2: A Highway Air Pollution Model.
EPA-600/8-80-018. Research Triangle Park, NC.
EPA, 1986. Guideline on Air Quality Models (Revised), EPA-450/2-78-027R. Research
Triangle Park, NC.
EPA, 1987. User's Guide for RAM. EPA-600/8-87-046. Research Triangle Park, NC.
EPA, 1990. User's Guide for the Urban Airshed Model. EPA-450/4-90-007a-g. Research
Triangle Park, NC.
EPA, 1992a. User's Guide to MOBILES (Mobile Source Emissions Factor Model).
EPA-AA-AQAB-92-01. Ann Arbor, MI.
EPA, 1992b. Evaluation of CO Intersection Modeling Techniques Using a New York City
Database. EPA-454/R-92-004. Research Triangle Park, NC.
EPA, 1992c. User's Guide to CAL3QHC Version 2.0: A Modeling Methodology for
Predicting Pollutant Concentrations Near Roadway Intersections.
EPA-454/R-92-006. Research Triangle Park, NC.
Garber, N., 1988. Traffic and Highway Engineering. Department of Engineering,
University of Virginia, Charlottesville, Virginia.
Highway Research Board (HRB), 1965. Highway Capacity Manual: Special Report 87.
Washington, D.C.
NYSDOT, 1982. Intersection Midblock Model User's Guide. New York State Department
of Transportation, Albany, NY.
Transportation Research Board (TRB), 1985. Highway Capacity Manual: Special Report
209 Washington, D.C.
6-2
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TECHNICAL REPORT DATA
(Please read Instructions on the reverse before completing)
1. REPORT NO.
EPA-454/R-92-005
2.
3. RECIPIENT'S ACCESSION NO.
4. TITLE AND SUBTITLE
Guideline for Modeling Carbon Monoxide from Roadway
Intersections
5. REPORT DATE
November 1992
6. PERFORMING ORGANIZATION CODE
7. AUTHOR(S)
Donald C. DiCristofaro
8. PERFORMING ORGANIZATION REPORT NO.
9. PERFORMING ORGANIZATION NAME AND ADDRESS
Sigma Research Corporation
Concord, MA 01742
10. PROGRAM ELEMENT NO.
11. CONTRACT/GRANT NO.
12. SPONSORING AGENCY NAME AND ADDRESS
13. TYPE OF REPORT AND PERIOD COVERED
Office of Air Quality Planning and Standards
U.S. Environnvental Protection Agency
Research Triangle Park, NC 27711
14. SPONSORING AGENCY CODE
15. SUPPLEMENTARY NOTES
16. ABSTRACT
•
Carbon Monoxide (CO) State Implementation Plan (SIP) attainment demonstrations and
project-level conformity analysis are required under the Clean Air Act Amendments
of 1990. Intersection modeling is recommended to meet these requirements. -The
purpose of this document is to provide guidance for performing CO intersection
modeling. The modeling guidance includes selecting intersections, siting receptors,
meteorological inputs, background concentrations, estimating 8-hour concentrations
from 1-hour concentrations, and examples.
17.
KEY WORDS AND DOCUMENT ANALYSIS
DESCRIPTORS
b. IDENTIFIERS/OPEN ENDED TERMS C. COSATI E;ield/Group
Carbon Monoxide (CO)
Intersection Modeling
State Implementation Plan (SIP)
Clean Air Act Amendments
Hot Spot Modeling
18. DISTRIBUTION STATEMENT
19. SECURITY CLASS (This Report)
21. NO. OF PAGES
65
2O. SECURITY CLASS (This page)
22. PRICE
EPA Form 2220-1 (Rev. 4-77)
PREVIOUS EDITION IS OBSOLETE
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