United States
Environmental Protection
Agency
Office of Air Quality
Planning and Standards
Research Triangle Park, NC 27711
EPA-454/R-92-006R
September 1995
Air
EPA USER'S GUIDE TO CAL3QHC
VERSION 2.0: A MODELING
METHODOLOGY FOR PREDICTING
POLLUTANT CONCENTRATIONS
NEAR ROADWAY INTERSECTIONS
(REVISED)
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EPA-454/R-92-006
(Revised)
User's Guide to CAL3QHC Version 2.0:
A Modeling Methodology for Predicting
Pollutant Concentrations Near
Roadway Intersections
U.S. Environmental Protection Agency
Office of Air Quality Planning and Standards
Research Triangle Park, NC 27711
September, 1995
U.S. Environmental Protection Agency
Region 5, Library (PL-12J)
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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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PREFACE
The CAL3QHC Version 2.0 model has been slightly revised. The revisions to the
model are reflected in this version of the user's guide. The CAL3QHC Version 2.0 input
structure has been converted from a "fixed format" to a "free format". Also, the
CAL3QHC source code has been enhanced to permit the calculating of Particulate Matter
(PM) concentrations. These revisions to CAL3QHC Version 2.0 will not change previous
model results.
in
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TABLE OF CONTENTS
Page
PREFACE iii
LIST OF FIGURES vi
LIST OF TABLES viii
ACKNOWLEDGEMENTS ix
1 INTRODUCTION 1
2 BACKGROUND 3
3 MODEL DESCRIPTION 7
3.1 Overview 7
3.2 Site Geometry 7
3.2.1 Free Flow Links 9
3.2.2 Queue Links 9
3.2.3 Receptor Locations 11
3.3 Emission Sources 11
3.3.1 Free Flow Links 12
3.3.2 Queue Links 13
3.4 Queuing Algorithm 15
3.4.1 Overview 15
3.4.2 Queue Estimation for Under-Saturated Conditions 19
3.4.3 Queue Estimation for Over-Saturated Conditions 21
3.5 Dispersion Component 24
3.6 Future Research Areas 24
4 USER INSTRUCTIONS 27
4.1 Data Requirements 27
4.2 Limitations and Recommendations 28
4.3 Input Description 32
IV
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TABLE OF CONTENTS (Continued)
Page
4.4 Run Procedure 39
4.5 Output Description 39
4.6 Examples 40
4.6.1 Example 1: Two-way Signalized Intersection
(Under-Capacity) 41
4.6.2 Example 2: Two-way Multiphase Signalized
Intersection (Over-Capacity) 41
4.6.3 Example 3: Urban Highway 42
5 SENSITIVITY ANALYSIS 73
5.1 Overview 73
5.2 Signal Timing 75
5.3 Traffic Volume on the Queue Link 75
5.4 Traffic Lanes in the Queue Link 78
5.5 Traffic Parameters 78
6 MODEL VALIDATION 81
6.1 Overview 81
6.2 The New York City Database 81
6.3 Modeling Methodology 82
6.4 Model Evaluation Results 83
6.4.1 Regulatory Default Analysis 83
6.4.2 Scoring Scheme Results 83
References 89
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LIST OF FIGURES
Figure Title and Description Page
1 Flowchart for CAL3QHC routines 8
2 Link and receptor geometry 10
3 Flowchart for queue link calculations 16
4 Queue and delay relationships for a near-saturated
signalized intersection 18
5 Queue and delay relationships for an over-saturated
signalized intersection 22
6 Example 1: Geometric configuration for a two-way
intersection (units are in feet) 43
7 Example 2: Geometric configuration for a two-way
multiphase intersection (units are in meters) 52
8 Example 3: Geometric configuration for an urban
highway (units are in feet) 64
9 Sensitivity analysis example run 74
10a Variation of CO concentrations (ppm) at receptor 1
(corner) versus wind angle for three different
values of signal timing: 30% red time (V/C = 0.75,
queue = 5.6), 40% red time (V/C = 0.88, queue = 9.0),
and 50% red time (V/C = 1.08, queue = 42.9) 76
10b Same as Figure 10a except at receptor 2 (mid-block) 76
11a Variation of CO concentrations (ppm) at receptor 1
(corner) versus wind angle for three different
values of approach traffic volume: 1000 vph
(V/C = 0.59, queue = 5.0), 1500 vph (V/C = 0.88,
queue = 9.0), and 2000 vph (V/C = 1.18, queue = 93.5) 77
11 b Same as Figure 11 a except at receptor 2 (mid-block) 77
VI
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LIST OF FIGURES (Continued)
Figure Title and Description Page
12a Variation of CO concentrations (ppm) at receptor 1
(corner) versus wind angle for different number of
traffic lanes: two traffic lanes (V/C = 0.88,
queue = 9.0) and three traffic lanes (V/C = 0.59,
queue = 5.0) 79
12b Same as Figure 12a except at receptor 2 (mid-block) 79
13 The composite model comparison measure (CM) with 95%
confidence limits using CPM statistics 87
14 CM with 95% confidence limits using the AFB of
scientific category 1 88
VII
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LIST OF TABLES
Table Title and Description Page
1 Surface Roughness for Various Land Uses 30
2 Description of Type of Variables 38
3 Example-1: Two way Signalized Intersection
(Under-Capacity) 44
4 Example-2: Two way Multiphase Signalized Intersection
(Over-Capacity) 53
5 Example-3: Urban Highway 65
6 Comparison of Top-Ten Observed Concentrations with
CAL3QHC Predicted Concentrations 84
VIII
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ACKNOWLEDGEMENTS
Peter Eckhoff of EPA has revised the CAL3QHC Version 2.0 model and user's guide to
allow input data in "free format" and to allow for the analysis of Particulate Matter (PM)
impacts.
The original CAL3QHC Version 2.0 User's Guide was prepared for the United States
Environmental Protection Agency (EPA), Office of Air Quality Planning and Standards
(OAQPS) under contract No. 68-D90067. The authors, Guido Schattanek and June Kahng,
would like to express special acknowledgements to the EPA technical director, Thomas N.
Braverman, for his guidance and assistance in resolving technical issues, and to Donald C.
DiCristofaro of Sigma Research Corporation, Concord, Massachusetts, for his contribution
to the update of Chapters 4, 5, and 6, and the overall compilation of the report.
The initial User's Guide to CAL3QHC was prepared in 1990 for the EPA/OAQPS under
Contract No. 68-02-4394 by the authors at Parsons Brinckerhoff Quade & Douglas, Inc. in
New York, New York. Special acknowledgements for their contribution to the initial report
are given to Thomas Wholley who provided the first concept of CAL3Q and offered
technical guidance; George Schewe (Environmental Quality Management) for his assistance
and direction in this effort; John Sun (Bechtel/Parsons Brinckerhoff) whose initial
recommendations led to the use of Highway Capacity Manual procedures; James Brown
and Joel Soden (Parsons Brinckerhoff) for their guidance and review of this document; and
Tereza Stratou, Steven Warshaw, and Ingrid Eng for their Fortran programming efforts.
IX
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SECTION 1
INTRODUCTION
CAL3QHC is a microcomputer based model to predict carbon monoxide (CO) or other inert
pollutant concentrations from motor vehicles at roadway intersections. The model includes
the C A LINE-3 line source dispersion model1 and a traffic algorithm for estimating vehicular
queue lengths at signalized intersections.
CALINE-3 is designed to predict air pollutant concentrations near highways and arterial
streets due to emissions from motor vehicles operating under free flow conditions.
However, it does not permit the direct estimation of the contribution of emissions from
idling vehicles. CAL3QHC enhances CALINE-3 by incorporating methods for estimating
queue lengths and the contribution of emissions from idling vehicles. The model permits
the estimation of total air pollution concentrations from both moving and idling vehicles. It
is a reliable tool2 for predicting concentrations of inert air pollutants near signalized
intersections. Because idle emissions account for a substantial portion of the total
emissions at an intersection, the model is relatively insensitive to traffic speed, a parameter
difficult to predict with a high degree of accuracy on congested urban roadways without a
substantial data collection effort.
CAL3QHC requires all the inputs required for CALINE-3 including: roadway geometries,
receptor locations, meteorological conditions and vehicular emission rates. In addition,
several other parameters are necessary, including signal timing data and information
describing the configuration of the intersection being modeled.
The principal difference between the original CAL3QHC model and CAL3QHC Version 2.0
pertains to the calculation of intersection capacity, vehicle delay, and queue length.
Version 2.0 includes three new traffic parameters: Saturation Flow Rate, Signal Type, and
Arrival Type. These parameters permit more precise specification of the operational
characteristics of an intersection than in the original CAL3QHC model. Version 2.0 also
replaces "stopped" delay (used in the queue calculation) with "approach" delay. These
modifications are based on recommendations from the 1985 Highway Capacity Manual
(HCM)3. CAL3QHC Version 2.0 can accommodate up to 120 roadway links, 60 receptor
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locations, and 360 wind angles, an increase from the original version which could
accommodate 55 links and 20 receptors. This allows the modeling of adjacent
intersections that interact with each other within a short distance.
The revised CAL3QHC Version 2.0 converts the input structure from "fixed format" to
"free format." In addition, the revised CAL3QHC Version 2.0 model allows for the analysis
of Particulate Matter (PM) impacts in micrograms per cubic meter.
This User's Guide is intended to provide the information necessary to run CAL3QHC
Version 2.0. Development of the model is discussed in Section 2. Section 3 contains a
technical description of how the different components and algorithms operate within the
program. In addition, future research areas are discussed in Section 3. Model inputs and
outputs, instructions for executing the model on a personal computer, and example
applications are contained in Section 4. Section 5 presents a sensitivity analysis evaluating
the effect of changes in model inputs on resultant pollutant concentration estimates.
Section 6 summarizes the results of model verification tests completed by the United
States Environmental Protection Agency 2.
While this document includes information on CALINE-3 necessary for using the CAL3QHC
model, it does not describe the theory underlying CALINE-3. It is recommended that the
user consult the CALINE-3 User's Guide1 for information on the theoretical aspects of
CALINE-3.
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SECTION 2
BACKGROUND
When originally published in 1978, Volume 9 of the EPA Guidelines for Air Quality
Maintenance Planning and Analysis4 was considered to be the most appropriate
methodology for calculating CO concentrations near congested intersections. The
workbook procedure described in Volume 9 is composed of three components: traffic,
emissions, and dispersion. Although no one model has been developed to replace all of the
procedures in Volume 9, various procedures have been devised that have improved each
component.
The manual workbook procedures included in Volume 9 are cumbersome and time
consuming to use in situations where there are numerous roadway intersections or multiple
traffic alternatives. In addition, Volume 9 utilizes an outdated modal emissions model, and
its procedures are limited to situations where the estimated volume of traffic (V)
approaching an intersection is less than the theoretical capacity (C) of the intersection
(V/C<1). Consequently, during the period 1985 to 1987, Thomas Wholley and Thomas
Hansen from the U.S. EPA Regional Offices I and IV developed CAL3Q, a computer-based
procedure for estimating CO concentrations near roadway intersections. CAL3Q used the
running and idling emission rates from the U.S. EPA mobile source emission factor model
to estimate emissions, a queuing algorithm developed by the Connecticut Department of
Transportation (CONDOT) to estimate queue lengths, and the CALINE-3 line source
dispersion model to estimate dispersion.
While CAL3Q provided a means for considering the effect of queuing vehicles on pollutant
concentrations, testing of the model indicated that it failed to accurately estimate queue
lengths under near-saturated and over-saturated traffic conditions (i.e., when the approach
volume reaches or surpasses the capacity of the roadway). Since these conditions are
common occurrences in many congested urban areas and are of particular concern in
determining the worst (maximum) air quality impacts of a proposed action, an extensive
reevaluation of the traffic assumptions used in determining delays and queue lengths at
congested intersections was undertaken.
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One of the principal recommendations of the re-evaluation was to replace the delay
formulas included in CAL3Q with a hybrid methodology based on the signalized
intersection analysis technique presented in the 1985 Highway Capacity Manual (HCM)3
and the Deterministic Queuing Theory5-6. In the hybrid methodology, a simplified 1985
HCM procedure is used to estimate the average vehicle delay for the under-saturated
condition. The additional delay associated with over-saturation conditions is estimated
based on the Deterministic Queuing Theory procedure. Using the average vehicle delay
estimated through the hybrid methodology, queue length is subsequently estimated based
on a queuing formula developed by Webster7-8 and the Deterministic Queuing Theory. The
revised version of CAL3Q was named CAL3QHC, and was applied extensively to model
conditions near locations where traffic conditions were near or over the capacity of the
intersection, and at complex intersections where roadways interacted with ramps and
elevated highways.
During 1989-1990the U.S. EPA commissioned a performance evaluation of eight
intersection models. The results of this study indicated that of the models tested,
CAL3QHC performed well in predicting CO concentrations in the vicinity of a congested
intersection. Based on the results of that evaluation, the original CAL3QHC User's Guide
was prepared for EPA OAQPS and released in September 1990. On February 13, 1991,
EPA issued a notice of proposed rulemaking identifying CAL3QHC as the recommended
model for estimating carbon monoxide concentrations in the vicinity of intersections.
During 1991, comments were received in response to the proposed rulemaking and as part
of the Fifth Conference on Air Quality Modeling. Most of the commentors pointed out
that, given the great degree of variability in the operational characteristics of a signalized
intersection, more consideration should be given to the calculation of delay and
intersection capacity.
In order to address these comments, the model has been revised to: (1) give the user
more options in determining the capacity of an intersection, and (2) consider the effects of
different types of signals and arrival rates. All the changes were based on
recommendations from the 1985 HCM.
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During 1991, EPA sponsored another evaluation2 of the performance of eight different
modeling methodologies (including CAL3QHC Version 2.0) in estimating CO concentrations
using both the MOBILE4 and MOBILE4.1 emission factor models. The data used for this
evaluation were collected during 1989-1990 as part of a major air quality study performed
in response to the proposed reconstruction of a portion of Route 9A in New York City, and
included traffic, meteorological, and CO data collected at six intersections during a three-
month period. The results of this evaluation indicated that CAL3QHC was one of the best
performing models.
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SECTION 3
MODEL DESCRIPTION
3.1 OVERVIEW
CAL3QHC is a consolidation of the CALINE-3 line source dispersion model1 and an
algorithm that estimates the length of the queues formed by idling vehicles at signalized
intersections. The contribution of the emissions from idling vehicles is estimated and
converted into line sources using the CALINE-3 link format. CAL3QHC requires all input
parameters necessary to run CALINE-3 plus the following additional inputs: idling emission
rates, the number of "moving" lanes in each approach link and the signal timing of the
intersection. Version 2.0 of CAL3QHC also includes three additional traffic parameters
that must be provided by the user: Saturation Flow Rate, Signal Type, and Arrival Type.
Figure 1 depicts the major routines of the CAL3QHC program and how they interact. A
description of these routines and how each input parameter is used in the model is
provided below.
3.2 SITE GEOMETRY
CAL3QHC permits the specification of up to 120 roadway links and 60 receptor locations
within an.XYZ plane. The Y-axis is aligned due north, with wind angle inputs to the model
following accepted meteorological convention -- e.g. 270° represents a wind from the
west. The positive X-axis is aligned due east. A link can be specified as either a free flow
or a queue link. The program automatically sums the contributions from each link to each
receptor. Surface roughness and meteorological variables (such as atmospheric stability,
wind speed and wind direction) are assumed to be spatially constant over the entire study
area.
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( START J
INPUT
SITE VARIABLES AND
RECEPTOR INFORMATION
CALCULATE THETA,
ANGLE FORMED BY
ASSUMED QUEUE L
AND THE COORDINATE
THE
THE
IN<
SYSTEM
CALCULATE THE
LINK LENGTH CLL}
INPUT METEOROLOGICAL
DATA AND WIND
DIRECTION VARIATION
INDUT NEW
METEOROLOGICAL DATA
OUTPUT LINK CO
CONCENTRATION FOR
EACH RECEPTOR AND
WIND DIRECTION
CALINE3 DISPERSION
CALCULATIONS
[ NEXT WIND DIRECTION RANC
1 NEXT WIND DIRECTION
\
* 1
^
.«
Figure 1. Flowchart for CAL3QHC routines.
8
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3.2.1 Free Flow Links
A free flow link is defined as a straight segment of roadway having a constant width,
height, traffic volume, travel speed, and vehicle emission factor. The location of the link is
specified by its end point coordinates, X1, Y1, and X2, Y2 (see Figure 2). It is not
necessary to specify which way traffic is moving on a free flow link, but the link length
must be greater than link width for proper element resolution. A new link must be coded
when there is a change in width, traffic volume, travel speed or vehicle emission factor.
Link width is defined as the width of the travelled roadway (lanes of moving traffic only)
plus 3 meters (10 feet) on each side to account for the dispersion of the plume generated
by the wake of moving vehicles. Link height cannot be greater than 10 meters (elevated
section) or less than -10 meters (depressed section), since CALINE-3 has not been
validated outside of this range. In most cases (at grade section), a link height of 0 meters
should be used.
3.2.2 Queue Links
A queue link is defined as a straight segment of roadway with a constant width and
emission source strength, on which vehicles are idling for a specified period of time. The
location of a link is determined by its beginning point (i.e., X1, Y1 coordinates of the
locations at which vehicles start queuing at an intersection "stopping line") and an arbitrary
end point (i.e., X2, Y2 coordinates of any point along the line where the queue is forming.)
(See Figure 2). The purpose of specifying a queue link end point is to specify the direction
of the queue. The actual length of the queue is estimated by the program based on the
traffic volume and the capacity of the approach. (Section 3.4 describes how queue length
is estimated.)
Link width is determined by the width of the travelled roadway only (width of the lanes on
which vehicles are idling). Three meters are not added on each side since vehicles are not
moving and no wake is generated. Lane widths typically vary between 10 feet (3 m) and
12 feet (4 m) per lane depending on site characteristics.
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Xfi.YB.ZB
CRECEPTOR COORDINATES;)
X1.Y1 CBEGINNING OF FREE FLOW L INK)
X1.Y1 CBEGINNING OF QUEUE LINK) - STOPPING LINE
QUEUE LINK WiDTH CTRAVELLED WAY ONLY)
FREE FLOW LINK WIDTH CTRAVELLED WAY^-20ft OR 6m)
X2.Y2 CpOINT ALONG THIS LINE, DETERMINES
DIRECTION OF QUEUE L I NtO
X2.Y2 CEND OF FREE FLOW
Figure 2. Link and receptor geometry.
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3.2.3 Receptor Locations
Receptor locations are specified in terms of X, Y, and Z coordinates. A receptor should be
located outside the "mixing zone" of the free flow links (i.e., total width of travel lanes
plus 3 meters (10 feet) on each of the outside travel lanes) (See Figure 2). The mixing
zone is considered to be the area of uniform emissions and turbulence. The 10 meter (32
foot) link-height restriction does not apply to receptor-height: receptors can be specified at
elevations greater than 10 meters (32 feet) if so desired. In most applications, receptors
are entered at an assumed breathing height of 1.8 meters.
3.3 EMISSION SOURCES
Separate emissions estimates must be provided as input data for each free flow and queue
link. Emissions from vehicles travelling from point "A" to point "B" are calculated using
the composite emission rate for the length of the link. (This composite emission rate is the
resultant of the average speed of a driving cycle that includes different levels of
acceleration and deceleration.) When vehicles are idling at an intersection (i.e., not
moving), emissions are calculated using the idle emission rate for the duration of the idling
time. While a sub-population of approach traffic experience idling (i.e., are queued), the
number of the queued vehicles varies significantly as discussed in section 3.4.
Although CAL3QHC can be used with any mobile source emission factor model, it is
recommended that carbon monoxide emission source strength be estimated using the most
recent version of the U.S. EPA mobile source emission factor model (MOBILE59 is currently
the most recent version of this program), or in California, where different automobile
emission standards apply, the most current version of EMFAC10 (Emission Factor program
for California). For Particulate Matter (PM) emission factors, the latest version of the
PART5 emission factor model is recommended.11
Pollutant concentration estimates are directly proportional to the emission factors used as
input data to the program. Consequently, the accuracy of the results of a microscale air
quality analysis is dependent on the accuracy of the emission factors used. The most
critical variables affecting the emission factors are: average link speed, vehicle operating
conditions (percent cold/hot starts), and ambient temperature.
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3.3.1 Free flow links
Vehicles are assumed to be travelling without delay along free flow links. The link speed
for a free flow link represents the speed of a vehicle travelling along the link in the absence
of the delay caused by traffic signals.
It is recommended that this free flow speed be obtained either from actual field
measurements or from a traffic engineer with adequate local knowledge of the
intersections under consideration. In the absence of these information sources, the use of
the free flow speeds presented on the following page may be considered within the
context of the locally posted speed limits. However, 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/vehicle conflicts and/or parking activities (e.g., Central Business Districts, Fringe
Business Districts), the use of substantially lower free flow speeds (e.g., 15 mph to 20
mph) may be warranted.
Free Flow Speeds for Arterials
(Source: 1985 Highway Capacity Manual3, Chapter 11)
Arterial Class i M ill
Range of free flow
speeds (mph) 35 to 45 30 to 35 25 to 30
Typical free flow
speeds (mph) 40 33 27
The criteria for the classification of arterials for use in conjunction with the free flow
speeds mentioned above, are presented as follows:
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Arterial Class According to
Function and Design Category
(Source: 1985 Highway Capacity Manual3, Chapter 11)
Functional Category
Principal Minor
Design Category Arterial Arterial
Suburban I II
Intermediate
(Suburban/Urban) II III
Urban III III
The composite running emission rate in "grams/vehicle mile" should be obtained for the
average link speed, operating conditions of the engine, and vehicle mix for each free flow
link using the current version of the U.S. EPA MOBILE emissions factor model, EMFAC, or
other appropriate emission estimation programs. {Appropriate inspection/maintenance
program, anti-tampering program, vehicle age distribution, and analysis year must be
specified to accurately develop emission rates.)
3.3.2 Queue Links
Vehicles are assumed to be in an idling mode of operation during a specified period of time
along a queue link. CAL3QHC assumes that vehicles will be in an idling mode of operation
only during the red phase of the signal cycle. Based on a user-specified idling emission
rate, the number of lanes of vehicles idling at the stopping line, and the percentage of red
time, CAL3QHC calculates the emission source strength and converts it to a line source
value, so that the CALINE-3 model can process it as a nominal free flow link. The strength
per unit length of a line source is not dependent on the approach traffic volume or
capacity. These parameters are only used to determine the length of the line source for
the queue link.
An idle emission factor in "grams per vehicle-hour" must be converted to "micrograms per
meter-second" to calculate linear source strength. "Grams per vehicle-hour" is converted
13
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to "micrograms per vehicle-hour" by multiplying by a million. "Micrograms per
vehicle-hour" is converted to "micrograms per vehicle-second" by dividing by 3600. Based
on the assumption that there is a distance of 6 meters (20 feet) per vehicle in a queue,
"micrograms per vehicle-second" is converted to "micrograms per meter- second" by
dividing by 6. Thus, by converting the units of the idling emission factor, the Linear
Source Strength (Q,) for "one traffic lane for one meter over one second" can be
determined as follows:
Idle Emission factor (g/veh-hr)x106
U/g/m-s]
3600 x 6
To determine the total Linear Source Strength (Q,) for a queuing link, the total number of
lanes in the queue link and the percent of time that vehicles are estimated to be idling in
the queue link must be considered. This is done by multiplying the Linear Source Strength
for one lane (Q,) by the number of traffic lanes in the link and the percent of red time
during the signal cycle. The total Linear Source Strength (Q,) for the queuing link in
"micrograms per meter- second" is calculated as follows:
Q, = Q, x number of lanes x percent red time [//g/m-s]
It is assumed that the vehicles will be in the idling mode of operation only
during the Red Time phase of the signal cycle.
CALINE-3 estimates total Linear Source Strength (Q,) as follows:
Q, = 0.1726x VPH x EF [//g/m-s]
where: VPH = Vehicles per hour
EF = Emissions factor (g/mi)
To convert the Linear Source Strength into the CALINE-3 format, CAL3QHC fixes one of
the two variables by assigning an arbitrary value of 100 to EF (as seen in the output line
for the queue link). VPH can then be calculated as follows:
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VPH =
0.1726x 100
As seen in the output line for the queue link, this VPH will give the appropriate total Linear
Source Strength for the queue link when multiplied by EF = 100.
Since the current MOBILE emissions model estimates idle emission rates in "grams per
vehicle hour", CAL3QHC Version 2.0 also requires that the idle emission rate be input in
"grams per vehicle hour." (It should be noted that the original CAL3QHC required idle
emission rate input in "grams per vehicle minute").
3.4 QUEUING ALGORITHM
3.4.1 Overview
Figure 3 depicts the queue length estimation procedure employed in CAL3QHC. The input
parameters required to determine the queue length are: traffic volume of the link, signal
cycle length, red time length, and clearance interval lost time. The following additional
parameters need to be specified:
SFR - saturation flow rate [vehicles per hour of effective green time, vphg]
ST - traffic signal type [pretimed ( = 1), actuated ( = 2), or semiactuated ( = 3)1
AT - "arrival type" of vehicle platoon [worst ( = 1) through most favorable ( = 5)]
The capacity of an intersection approach lane is determined by applying the effective green
time to its saturation flow rate (SFR). Saturation flow rate represents the maximum
number of vehicles that can pass through a given intersection approach lane assuming that
the approach lane had 100 percent of real time as effective green time3. CAL3QHC
Version 2.0 allows the input of 1600 vphg as a default saturation flow rate to represent an
urban intersection. Saturation flow rate may vary substantially from this default value
depending on site specific traffic conditions and site geometry.
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ASSUME TIME LOST GETTING
QUEUE IN MOTION IS
MAXIMUM C1=2 0 SEC
CALCULATE
GREEN TIME CGAVG3 =
Signal Lengtn CCAVG3 - Bea Time
RED TO CYCLE RATIO CRC) =
Red Time / 51 g.na I CycIe Lengt h
Intersection Approach Capacity CC} Vehicles/Lane/Hour
C = C3600/CAVGJ x CSFR/36003 x CGAVG-tl-YFAC}
wnere CAVG - cycle length
SFH = saturation flow rate
GAVG = green time
K1 = start up delay
YFAC = clearance interval lost time
INTERSECTION APPROACH
DELAY CD) CALCULATIONS
D = d * PF * Fc
where a = average stopped oeiay
PF = progression adjustment -factor
Fc = stooped oe Iav-to-approach aelay
conversion factor
CALCULATE
DEMAND - CAPACITY RATIO
V/C
wnere v = volume per lane
C = capacity per tanel
QUEUE LENGTH CALCULATION
Nu = Max[a > D * r/2 x Q, a x r]
where Q = volume per lane
D = intersection approach delay/vehicle/Iane
r = length o* red phase
QUEUE LENGTH CALCULATION
FOR OVER-CAPACITY
No = Nu* ' 3fv - C3
LL = LL* - 3i|V - Q
COMPUTE NEW LINE LENGTH
ASSUMING 6m PER VEHICLE
LL = Nu x 6
COMPUTE EMISSION HATE FOR LINK
TER = CIDLFAC x 1P?D x C.NLANES
BCD
COMPUTE THE VPL THAT
WILL PRODUCE THE APPROPRIATE
EMISSION SOURCE
VPL = TEH/0 1726 x 100 0
SET ASSUMED EMISSION FACTOR
EFL = 100 0
SEE FI CURE 1
Figure 3. Flowchart for queue link calculations.
16
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Effective green time is calculated by subtracting the amount of red time, start up delay
(2.0 seconds) and the time lost during the clearance interval12 from total signal cycle
length. The clearance interval lost time represents the portion of the yellow phase (i.e. the
period between the green and red phases) that is not used by the motorists. It's value is a
function of signal timing and driver characteristics. While a clearance interval lost time of
2 seconds is recommended as a default value to reflect "normal/average" driver behavior13,
the model permits the user to specify clearance lost time to reflect site-specific traffic
conditions (e.g., 0 to 1 seconds for "aggressive" drivers and 3 to 4 seconds for
"conservative" drivers)13.
Thus, the capacity of the intersection approach per lane is calculated as:
C = (SFR) x (CAVG - RAVG - K1- YFAC)
CAVG
where: C = hourly capacity per lane [veh/hr/lane]
SFR = saturation flow rate [veh/lane/hr of green time]
CAVG = cycle length [s]
RAVG = length of red phase [s]
K1 = start-up delay Is] = 2 s
YFAC = clearance interval lost time [s]
Vehicles arriving at a signalized intersection during the red phase queue-up behind the
stopping line of the approach. After the signal turns to green, the first vehicle on the
queue proceeds forward after a start-up delay of approximately 2 seconds, followed by the
remaining vehicles in the queue. This results in the propagation of a "shock-wave"
traveling backwards toward the last vehicle in the queue. Vehicles arriving during the
green phase prior to the dissipation of the queue are stopped and join the end of the
queue. Figure 4 illustrates this process, assuming a uniform vehicle arrival rate,
q [vehicles/lane/second], and a uniform departure rate, s [vehicles/lane/second] for a
near-saturated cycle (i.e., volume-to-capacity ratio, V/C, is close to 1). In Figure 4, the
vertical distance (Ay) between the cumulative arrival curve, A(t), and the cumulative
departure curve, D(t), represents the queue on each approach lane (i.e., the number of
vehicles idling) at time t5'6. The horizontal distance (Ax) between the two curves, t2 -1,,
represents the stopped delay experienced by the nth vehicle arriving at the intersection
17
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CUMULATIVE
NUMBER
OP VEHICLES
PER LANE
Cvehic les/ lane}
RED PHASE
GREEN PHASE
CUMULATIVE ARRIVALS PER LANE
(vehicles per lane} =
CUMULATIVE DEPARTURES PER LANE
Figure 4. Queue and delay relationships for a near-saturated signalized
intersection.
18
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approach lane at time t= t,. The total vehicle delay for each approach lane during the
cycle is represented by the area of the triangle OCF. When the approach is at a
near-saturation condition and the signal timing has a 50-50 split between red and green
time, (i.e., 50 percent of the cycle is red phase), the total vehicle delay per lane, W, may
be approximated as follows:
W = FB x OE x 1 /2
= FBx OF (1)
where: W = total vehicle delay per lane during a cycle [vehicles x
second/lane]
FB = average number of vehicles queued per lane at the beginning
of the green phase [veh]
OE = cycle length [s]
OF = the duration of the red phase [s]
Since CAL3QHC assumes that the queued vehicles idle only for the duration of the red
phase (i.e., average delay is equivalent to the duration of the red phase, OF), the
corresponding queue yielding a correct estimation of total vehicle delay per lane is defined
as FB, (i.e., the number of queued vehicles at the beginning of the green phase) using the
Equation (1).
3.4.2 Queue Estimation for Under-Saturated Conditions
In the under-saturated condition (i.e., volume to capacity ratio, v/c, is less than 1), the
number of vehicles queued at an intersection at the beginning of the green phase is
estimated based on the following formula from Webster7-8:
FB = Nu = MAX [q x D + r/2 x q, q x r] (2)
where: Nu = average queue per lane at the beginning of green phase in
under-saturated conditions [veh/lane]
q = vehicle arrival rate per lane [veh/lanes/s]
D = average vehicle approach delay [s/veh]
r = length of the red phase [s]
19
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For light traffic flow conditions, the second term of Equation (2), q x r gives a good
approximation of the queue at the beginning of the green phase. However, for heavier
traffic flow conditions, Webster found the first term, q x D + r/2 x q, produces a more
accurate estimate of the average queue at the beginning of the green phase. The first
component of the first term of Equation (2), q x D, represents the average queue length
throughout the signal cycle. The second component, r/2 x q, represents the average
fluctuation of the queue during the red phase. Since the queue generally reaches its
maximum at the end of the red phase (i.e., at the beginning of the green phase) in
under-saturated condition, these two components are added together in the first term to
estimate the average queue at the beginning of the green phase.
The average approach vehicle delay, D, in Equation (2) is estimated using the following
formula for signalized intersection delay given in Chapters 9 and 11 of the 1985 Highway
Capacity Manual (HCM)3:
D = d x PF x Fc (3)
where: d = average stopped delay per vehicle [s/veh]
PF = progression adjustment factor
Fc = stopped delay-to-approach delay conversion factor (= 1.3)
The first term in Equation (3), d, the average stopped delay per vehicle for an assumed
random arrival pattern for approaching vehicles, is estimated using the following formula
from the 1985 HCM:
d = (0.38) (CAVG)
1-
CAVG
CAVG
173X2
(X-1)
(4)
where:
GAVG = length of green phase [s]
CAVG = cycle length [s]
C = hourly capacity per lane [veh/hr/lane]
X =volume-to-capacity ratio = V/C
V = hourly approach volume per lane [veh/hr/lane]
20
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The first term of Equation (4) accounts for uniform delay, (i.e., the delay that occurs if the
arrival of vehicles is uniformly distributed over the cycle). The second term of the equation
accounts for additional delay due to random arrivals and/or occasional cycle failures.
The second term in Equation (3), the progression adjustment factor (PF), is included to
account for the variation of stopped delay with traffic flow progression quality.
Progression adjustment factors are determined using the following key variables:
Arrival Type (AT) - a general categorization of the way the platoon of vehicles
arrives at the intersection. Five arrival types are defined
in the 1985HCM:
1 = worst platoon condition (dense platoon arriving at the
beginning of the red phase)
2 = unfavorable platoon condition (dense or dispersed platoon
arriving during the red phase)
3 = average condition (random arrivals)
4 = moderately favorable platoon condition (dense or
dispersed platoon arriving during the green phase)
5 = most favorable platoon condition (dense platoon arriving
at the beginning of the green phase)
Signal Type (ST) - user may select one of the following three traffic signal
types:
1 = pretimed
2 = actuated
3 = semiactuated
3.4.3 Queue Estimation for Over-Saturated Conditions
In the over-saturation condition (i.e. volume to capacity ratio, V/C, greater than one), the
queue consists of the two components, N, and N2, as illustrated in Figure 5. A'(t) in
depicts the cumulative arrivals per lane in an over-saturated condition (i.e., V/C greater
than 1). A(t) represents the cumulative arrivals per lane during at-capacity condition (i.e.,
V/C equal to 1). Other symbols are similar to those defined in Figure 4. N, is the vertical
21
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CUMULATIVE
NUMBER
OF VEHICLES
PER LANE
vem c ies/ iane 3
TIME
t=1 hour
t=2 hours
Figure 5. Queue and delay relationships for an over-saturated signalized
intersection.
22
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difference between A(t) and D(t) and represents the normal fluctuation of a queue during
at-capacity conditions due to change of signal phase (i.e., from green to red, etc.). As
shown in Equation (5), the estimate of the average of N, at the beginning of the green
phase, denoted by Nu*, is identical to that of Nu, which can be estimated based on the
procedures provided in section 3.4.2.:
Nu* = MAX [q* xD* + r/2 x q*, r x q*] (5)
where: q* = vehicle arrival rate per lane during at-capacity operating conditions
(i.e. V/C = 1.0) [veh/lane/s]
D* = average vehicle delay during at-capacity operating conditions (i.e.
V/C = 1.0) [s/veh]
r = length of the red phase [s]
N2/ which is the vertical difference between A'(t) and A(t), represents the additional queue
resulting from over-saturation. In the over-saturated condition, N2 continues to grow until
the slope of A'(t) is lower than that of A(t). Thus, the average of N2, denoted by N2*, for
the first hour can be estimated as one half of the difference between the A'(t) and A(t) at t
= 1 hour as shown in the following equation:
N2* = 1/2 x [A'(t)-A(t)L at t = 1 hour
= 1/2x(V-C) (6)
where: N2* = average additional queue per lane due to over-saturation [veh/lane]
A'(t) = cumulative vehicular arrivals per lane in over-saturated condition
[veh/lane]
A(t) = cumulative vehicular arrivals per lane in at-capacity condition
[veh/lane]
V = hourly approach volume per lane (i.e., A'(t) at t = 1 hour)
[veh/lane/hr]
C = hourly capacity per lane (i.e., A(t) at t = 1 hour) [veh/lane/hr]
Therefore, the average queue at the beginning of the green phase during over-saturated
23
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conditions, N0, may be approximated by the following equation:
N0 = Nu* + N2»
MAX tq* xD* -I- r/2q",rxq*J + 1/2x(V-C) (7)
where: N0 = average queue per lane at the beginning of the green phase in an
over-saturated condition [veh],
q*, D*, r, V and C are the same as defined in Equations (5) and (6).
For both under- and over-saturated situations, the length of the queue link is calculated by
multiplying the number of vehicles in the queue by 6 m (20 ft) per vehicle. If the predicted
queue extends into the next intersection, it is recommended to stop the queue at the end
of the modeled block by adjusting the specified link endpoints.
3.5 DISPERSION COMPONENT
The dispersion component used in CAL3QHC is CALINE-3, a line source dispersion model
developed by the California Department of Transportation. CALINE-3 estimates air
pollutant concentrations resulting from moving vehicles on a roadway based on the
assumptions that pollutants emitted from motor vehicles travelling along a segment of
roadway can be represented as a "line source" of emissions, and that pollutants will
disperse in a Gaussian distribution from a defined "mixing zone" over the roadway being
modeled. For a complete discussion of the theory and application of CALINE-3 the user is
referred to CALINE-3: A Versatile Dispersion Model for Predicting Air Pollutant Levels Near
Highways and Arterial Streets1.
3.6 FUTURE RESEARCH AREAS
While CAL3QHC includes improved procedures for estimating air pollutant levels in the
vicinity of intersections, there remain potential areas of further study which could result in
higher levels of accuracy in completing air quality studies. These include:
24
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The derivation of queue length for the under-saturated condition (i.e., V/C less or
equal to 1) was simplified by assuming a near-capacity (i.e., V/C approximately equal
to 1) operation and an even-split of signal timing (i.e. 50% of the cycle length is
green phase). This procedure works the best for near and over-saturated conditions
(i.e., conditions of most concern) but it could be refined to produce a more precise
estimation of queue length for cases deviating significantly from the assumed
condition.
The average additional queue due to over-saturation was assumed to be idling only
during the red phase of the signal cycle. Further investigation is required to fully
validate this assumption.
While the model provides the general concept for estimating emissions at signalized
intersections, there remain other traffic controls, such as stop signs or toll plazas,
where a similar concept could be extended. Future research and testing is necessary
to adapt this program for such situations.
The model assumes flat topography. Its handling of vehicular queuing could be
adapted to urban canyon situations.
25
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SECTION 4
USER INSTRUCTIONS
4.1 DATA REQUIREMENTS
The accuracy of the results of a microscale air quality analysis is directly dependent on the
accuracy of the input parameters. Meteorology, traffic, and emission factors can vary
widely and in many situations there is a great degree of uncertainty in their estimation.
The user should have a high degree of confidence in these data before proceeding to apply
the model. It is recommended that the user contact the EPA or appropriate state or local
air pollution control agency prior to selecting meteorological parameters and estimating
composite running and idling emission factors, since these factors depend on many
variables unique to a particular region (e.g., thermal state of engines, ambient air
temperatures, local inspection and maintenance program, and anti-tampering credits all
vary by region).
The following parameters are required input to the program, (Section 4.2 provides
recommendations on how to use these factors and Section 4.3 describes their location in
the input file):
Meteorological Variables:
Averaging Time [min]
Surface Roughness coefficient [cm]
Settling Velocity [cm/s]
Deposition Velocity [cm/s]
Wind Speed [m/s]
Stability Class [1 to 6 = A to F]
Mixing Height [m]
Site Variables:
Roadway Coordinates [X,Y,Z] [m or ft]
Roadway Width [m or ft]
Receptor Coordinates [X,Y,Z] [m or ft]
27
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Traffic Variables:
Traffic Volume [each link] [veh/hr]
Traffic Speed [each link] [mi/hr]
Average Signal Cycle Length [each intersection] [s]
Average Red Time Length [each approach] [s]
Clearance Lost Time [s]
Saturation Flow Rate [veh/hr]
Signal Type [pretimed, actuated, or semiactuated]
Arrival Rate [worst, below average, average, above average, best
progression]
Emission Variables:
Composite Running Emission Factor [each free flow link] [g/veh-mi]
Idle Emission Factor [each queue link] [g/veh-hr]
4.2 LIMITATIONS AND RECOMMENDATIONS
CAL3QHC can process up to 120 links and 60 receptor locations for all 360 degree
wind angles. A new link is required when there is a change in link width, traffic
volume, travel speed or emission factor.
In specifying link geometry, link length must always be greater than the link width.
Otherwise, correct element resolution cannot be calculated (error message will
appear).
Since emissions from idling vehicles account for a substantial portion of the total
emissions from an intersection, it is recommended that roadway segments up to
1000 feet from the intersection of interest be included in the site geometry. Testing
of the model indicates that links beyond 1000 feet from the receptor locations will
have a minor contribution to the results.
In overcapacity situations, where V/C > 1, the " model predicted queue length"
could be larger than the physical roadway configuration. The user could either revise
the traffic assumption for the link, or limit the length of the queue by running the
28
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analysis in the following manner: 1) input the queue link as a free flow link; 2)
specify X1, Y1, X2, Y2 coordinates that determine the physical limits of the queue
(i.e., the physically largest queue length); and 3) input the emission source as the
equivalent VPH (from the output run on the queue link) with an emission rate of
EF= 100. This will provide the appropriate emission source for the queue link with
the manually determined queue length.
When the site specific clearance lost time (portion of the yellow phase that is not
used by motorist) is unknown, a default value of 2 seconds may be used.
Source height should be within ± 10 m (± 32 ft), ( +10 m for an elevated roadway
section and -10m for a depressed section). CALINE-3 has not been validated
outside this range (error message will appear). In most applications (at-grade), a
source height of 0 m should be used.
Receptor height should be greater than the roadway height, except for elevated
roadway sections, since CALINE-3 assumes plume transport over a horizontal plane.
The 10 m height limitation does not apply to receptors; which may be placed at any
height above the roadway. For most applications, receptors should be placed at an
assumed breathing height of 1.8 m.
Wind speed should be at least 1 m/s. (CALINE-3 has not been validated for wind
speeds below 1 m/s).
Surface roughness coefficient (z0) should be within the range of 3 cm to 400 cm.
Table 1, which is reprinted from the CALINE-3 manual, provides the recommended
surface roughness coefficients for various land uses.
Averaging time should be within the range of 30 min to 60 min. The most common
value is 60 min, since most predictions are performed for a one hour period.
Mixing height should be generally set at 1000 m. CALINE-3 sensitivity to mixing
height is significant only for extremely low values (much less than 100 m).
29
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TABLE 1
SURFACE ROUGHNESS LENGTHS (Z0) FOR VARIOUS LAND USES
Type of Surface
Smooth desert
Grass (5-6 cm)
Grass (4 cm)
Alfalfa (15.2cm)
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
30
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Free flow link width should be equal to the width of the traveled roadway plus 3 m
(10 ft) on each side of the roadway (to account for the mixing zone created by the
dispersion of the plume generated by the wake of moving vehicles).
Queue link width should be equal to the width of the traveled roadway only.
Receptors should always be located outside of the mixing zone (link width) of the
free flow and queue links. In the case of urban intersections, where buildings are
located closer than 3 m (10 ft) from the roadway and the speed of the traffic is very
slow, a reduced mixing zone should be considered to maintain receptor locations
outside of the mixing zone.
It is recommended that the link speed information be obtained from traffic engineers
familiar with the area under consideration. The link speed for a free flow link
represents the speed experienced by drivers travelling along the link in the absence of
the delay caused by traffic signals. In the absence of recommended information from
traffic engineers, the use of the free flow speeds presented in Section 3.3.1 may be
considered.
The saturation flow rate or the hourly capacity per lane should be determined by the
user depending on the characteristics and operation of the intersection. A default
value of 1600 vehicles per hour, which is representative of an urban intersection,
may be used in the absence of locally derived values.
The signal type should be input as:
1 = Pretimed
2 = Actuated
3 = Semiactuated
In the case of actuated or semiactuated signals, the user must input the estimated
red time for each approach.
31
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The arrival type should be input as:
1 = Worst progression (dense platoon at beginning of red)
2 = Below average progression (dense platoon during middle of red)
3 = Average progression (random arrivals)
4 = Above average progression (dense platoon during middle of green)
5 = Best progression (dense platoon at beginning of green)
Note: If CAL3QHC were used to predict CO concentrations near highways or arterial
streets where only free flow links interact (i.e., not for a signalized intersection),
it would produce the same results as CALINE-3.
4.3 INPUT DESCRIPTION
The revised CAL3QHC Version 2.0 input has been converted to a free format for easier
and more error-free input generation. The line by line structure remains the same, while
the exact column positional placement of each value is no longer necessary. However,
because of its free format nature, single quotes need to be placed around all input
character data such as 'titles', 'run names', 'link and receptor names', 'grade type (TYP)'
and 'angle variation flags (VAR)'. Also, all data that may have been previously omitted
using the old format, needs to be entered. Actual, default, or 0 values need to be entered
on the appropriate line for each variable.
An additional variable, MODE, has also been added to Line Number 3 of the input file
structure. This variable allows the user to calculate either CO or Particulate Matter (PM)
concentrations. CO output concentration averages are in parts per million (ppm) while PM
concentration averages are in micrograms per cubic meter. The following is a tabular
description of the CAL3QHC Version 2.0 variables.
32
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LINE VARIABLE VARIABLE
NUMBER NAME TYPE
VARIABLE DESCRIPTION
'JOB'
ATIM
ZO
VS
VD
NR
SCAL
IOPT
IDEBUG
'RCP'
XR
Character
Real
Real
Real
Real
Integer
Real
Integer
Integer
Character
Real
Current job title (Limit of 40 Characters).
Averaging time [min].
Surface roughness [cm].
Settling velocity [cm/s].
Deposition velocity [cm/s].
Number of receptors,max = 60.
Scale conversion factor [if units are in
feet enter 0.3048, if they are in meters
enter 1.0].
Metric to english conversion in output
option. Enter "1" for output in feet.
Otherwise, enter a "0" for output in
meters.
Debugging option. Enter "1" for this
option which will cause the input data to
be echoed onto the screen. The echoing
process stops when an error is detected.
Enter a "0" if the debugging option is not
wanted.
Receptor name (Limit of 20 Characters).
X-coordinate of receptor.
33
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LINE
NUMBER
VARIABLE
NAME
VARIABLE
TYPE
VARIABLE DESCRIPTION
YR
ZR
Real
Real
Y-coordinate of receptor.
Z-coordinate of receptor.
Repeat line 2 for NR (number of receptors) times * *
'RUN'
NL
NM
PRINT2
IQ
Character
Integer
Integer
Integer
'MODE' Character
Integer
Current run title (Limit of 40 Characters).
Number of links, max= 120.
Number of meteorological conditions,
unlimited number. Each unique wind
speed, stability class, mixing height, or
wind angle range constitutes a new
meteorological condition.
Enter "1" for the output that includes the
receptor - link matrix tables (Long
format), enter "0" for the summary
output (Short format).
Enter 'C' for CO or T' for Particulate
Matter (PM) calculations.
Enter "1" for free flow and "2" for queue
links
5a
* * * * Enter lines 5a and 5b for IQ = 2 (queue link). * * * *
* * * « Enter line 5c for IQ = 1 (free flow link)
'LNK'
TYP'
XL1
Character
Character
Real
Link description (Limit of 20 Characters).
Link type. Enter 'AG' for "at grade" or
'FL' for "fill," 'BR' for "bridge" and 'DP'
for "depressed".
Link X-coordinate for end point 1 at
intersection stopping line.
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LINE VARIABLE VARIABLE
NUMBER NAME TYPE
VARIABLE DESCRIPTION
5b
YL1
XL2
YL2
HL
WL
NLANES
CAVG
RAVG
YFAC
IV
IDLFAC
SFR
ST
Real
Real
Real
Real
Real
Integer
Integer
Integer
Real
Integer
Real
Integer
Integer
Link Y-coordinate for end point 1 at
intersection stopping line.
Link X-coordinate for end point 2.
Link Y-coordinate for end point 2.
Source height.
Mixing zone width.
Number of travel fanes in queue link.
Average total signal cycle length [s].
Average red total signal cycle length [s].
Clearance lost time (portion of the yellow
phase that is not used by motorist) [s].
Approach volume on the queue link
[veh/hr].
Idle emission factor [g/veh-hr].
Saturation flow rate [veh/hr/lane]. Enter
1600 for a default value.
Signal type. Enter 1 for pretimed, 2 for
actuated, 3 for semiactuated. Enter 1 for
a default value.
AT
Integer
Arrival rate. Enter 1 for worst
progression, 2 for below average
progression, 3 for average progression, 4
for above average progression, 5 for best
progression. Enter 3 for a default value.
35
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LINE VARIABLE VARIABLE
NUMBER NAME TYPE
VARIABLE DESCRIPTION
5c
Link description (Limit of 20 Characters).
Link type. Enter 'AG' for "at grade" or
TL' for "fill," 'BR' for "bridge" and 'DP'
for "depressed".
XL1
YL1
XL2
YL2
VPHL
EFL
HL
WL
* * * Repeat
U
BRG
CLAS
MIXH
AMB
Real
Real
Real
Real
Real
Real
Real
Real
lines 4 and
Real
Real
Integer
Real
Real
Link X-coordinate for end point 1 .
Link Y-coordinate for end point 1 .
Link X-coordinate for end point 2.
Link Y-coordinate for end point 2.
Traffic volume on link [veh/hr].
Emission factor [g/veh-mi].
Source height.
Mixing zone width.
5 for NL (number of links) times ***
Wind speed [m/s].
Wind direction (angle from which the
wind is coming). Enter 0 if wind direction
variation data follow. Enter actual wind
direction, if only one wind direction will
be used.
Stability class.
Mixing height [m].
Ambient background concentration
[ppm].
36
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LINE VARIABLE VARIABLE
NUMBER NAME TYPE
VARIABLE DESCRIPTION
'VAR'
DEGR
VAK1!
VAI(2)
Character
Integer
Integer
Integer
Enter 'Y' if wind direction variation data
follow. Enter 'N' if only one wind
direction [BRG] will be considered.
Wind direction increment angle [degrees].
Lower boundary of the variation range
(First increment multiplier).
Upper boundary of the variation range
(Last increment multiplier).
* * * Repeat line 6 for each time that new * * *
* * * meteorological conditions * * *
* * * are to be run * * *
37
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TABLE 2
DESCRIPTION OF TYPE OF VARIABLES
VARIABLE
TYPE
EXPLANATION
CHARACTER
INTEGER
REAL
A string of alphanumeric characters that are bracketed by
single quotes, (e.g. 'Lanes 1, 2 & 3 Northbound')
A number with no decimal point, (e.g. 12)
A number with a decimal point separating the whole
number part from the fractional number part. (e.g.
234.16)
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4.4 RUN PROCEDURE
CAL3QHC is designed to operate on any IBM compatible personal computer. A math
co-processor is not required, but its use will speed the overall program run time
considerably. The memory requirements are 512 KB. A hard disk is not needed, but if it is
available, the program should be copied onto the hard disk.
To execute the program, at the DOS prompt, type:
CAL3QHC < input file name > < output file name >
If a CAL3QHC file produced for the original version is run with Version 2.0, the idle
emission factor must be input in grams per hour (instead of the original grams per minute).
The rest of the input format is the same with the exception of the addition of traffic
parameters.
4.5 OUTPUT DESCRIPTION
The output from CAL3QHC consists of printed listings showing a summary of all input
variables and model results.
The first page of the output format is divided into two sections:
The first section presents the site name, meteorological variables and ambient
background concentration.
The second section shows the link description and a list of the following link
specific parameters: X1, Y1, X2, Y2 coordinates (ft or m), the link length (ft or
m), BRG-the link direction (degrees), the type of link, the width (ft or m) and
height (ft or m) of the link, the link volume (VPH), and the emission factor (EF) in
g/veh-mi. In the case of queue links, VPH multiplied by EF = 100 represents
the strength of the appropriate emission source, as described in Section 3.3.2
Also, in the case of queue links, the V/C ratio is calculated and shown in the
39
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output. The last column shows the estimated number of vehicles in the queue.
(This number, multiplied by 6 m/veh, determines the length of the queue as used
in the program).
The second page of the output shows the queue specific input parameters:
cycle length, red time, clearance lost time, approach volume, saturation flow
rate, idle emission factor, signal type, and arrival rate.
The second section on the second page lists the receptor locations and the X, Y,
Z coordinates (in ft or m) for each receptor.
The third page lists the model results in parts per million (ppm). Two output versions are
available. The short version of the output (summary table) lists the total CO concentration
(ppm) at each receptor for each wind angle analyzed, together with the maximum total
concentration at each receptor with the corresponding angle. The long version of the
output prints the same summary table with the total CO concentrations for each receptor
as printed in the short version, plus a table showing the contribution from each link to the
total CO concentration at each receptor for the angle where the maximum total CO
concentration occurs.
In the case where multiple meteorological conditions are run, one printout with all the
results will be generated for each meteorological condition. The following section
describes three examples showing the different types of output that could be generated.
4.6 EXAMPLES
Three example cases are described in this section: 1) a signalized intersection with an
under-capacity situation where V/C ratios are less than 1.0 for all approaches; 2) a two
way multiphase intersection with an over-capacity situation, where V/C ratios are above
1.0 for some approaches; and 3) an urban highway where only free flow links interact.
In order to highlight how the model could be used, all these examples were kept as simple
as possible, however realistic values for traffic parameters, emission rates, and roadway
40
-------
configuration were used. For all cases, a map showing the geometric configuration of the
intersection being modeled is followed by a description of all input parameters and the
model input/output formats.
4.6.1 Example 1: Two-wav Signalized Intersection (Under-Capacity)
This intersection consists of a two-way main street intersecting a one-way local street.
Figure 6 shows the geometric configuration of the site and the X, Y coordinates of each
link and receptor location. Table 3 shows all the input parameters with their corresponding
units, in the same order as they are used in the input file.
4.6.2 Example 2: Two-wav Multiphase Signalized Intersection (Over-Capacity)
This example consists of a two-way main street with exclusive left turning bays
intersecting with a two-way local street. The signal cycle of this intersection is considered
a three phase signal, where the left turning movements from the main street (Northbound
and Southbound left turns) have an exclusive green phase, separate from the main street
green phase for the through traffic. Figure 7 shows the geometric configuration of the site
and the X, Y coordinates of each link and receptor locations. Table 4 shows all the input
parameters with their corresponding units, in the same order as they are used in the input
file.
In order to show a variation of the short output format, several wind angle ranges with
different wind speeds were run:
1st wind direction range from 150° to 210,° in 5° increments,
wind speed = 1 m/s
2nd wind direction range from 240° to 300° in 3° increments,
wind speed = 1 m/s
3rd wind direction range from 330° to 70° (430°) in 10° increments,
wind speed = 2 m/s
41
-------
4.6.3 Example 3: Urban Highway
This example consists of a two-way highway with an exit ramp, where only free flow links
interact. Figure 8 and Table 5 show the geometric configuration of the site and all the
input parameters with their corresponding units in the same order as they are used in the
input file.
In this case the long version of the output format is printed. The second page of the
output shows the summary table with results for all wind angles, and the third page shows
the contribution from each link for the angle producing the maximum concentration at each
receptor.
42
-------
CIO, 1000X-10. 1000D
REC 4
CIS.353
LOCAL STREET
REC 6
[-150,-353
REC 1
C45.-35)
QUEUE LtNK WIDTH = TRAVELLED WAT (20
FREE FLOW LI NK
WIDTH = TRAVELLED WAV +20
, * ! *
C-10,-1000X-10,-10003
Figure 6. Example 1: Geometric configuration for a two-way intersection (units
are in feet).
43
-------
TABLE 3
EXAMPLE -1: Two-way Signalized Intersection (Under-Capacity)
Input and output in feet
Description of Parameters:
Site Variables:
Averaging time (ATIM)
Surface roughness length (z0
Settling velocity (V8)
Deposition velocity (Vd)
Number of receptors
Scale conversion factor
Output in feet
Main St. NB Approach Link:
X1, Y1 coordinates
X2, Y2 coordinates
Traffic volume
Emission factor
Source height
Mixing zone width
Main St. NB Queue Link:
X1, Y1 coordinates
X2, Y2 coordinates
Source height
Mixing zone width
Number of travel lanes
Avg. signal cycle length
Avg. red time length
Clearance lost time
Approach traffic volume
Idle emission factor
Saturation flow rate
Signal type
Arrival rate
60 min
175 cm
0 cm/s
0 cm/s
8
0.3048(units are in ft)
1
10,-1000 (ft)
10,0 (ft)
1500 veh/hr
41.6g/veh-mi {*)
Oft
40ft
10,-10 (ft)
10,-1000 (ft)
0
20ft
2
90s
40s
3s
1500 veh/hr
735.0 g/veh-hr (**)
1600 veh/hr/lane
1 (pretimed)
3 (average progression)
44
-------
TABLE 3 (Continued)
Main St. NB Departure Link:
X1, Y1 coordinates
X2, Y2 coordinates
Traffic volume
Emission factor
Source height
Mixing zone width
Main St. SB Approach Link:
X1, Y1 coordinates
X2, Y2 coordinates
Traffic volume
Emission factor
Source height
Mixing zone width
Main St. SB Queue Link:
X1, Y1 coordinates
X2, Y2 coordinates
Source height
Mixing zone width
Number of travel lanes
Avg. signal cycle length
Avg. red time length
Clearance lost time
Approach traffic volume
Idle emission factor
Saturation flow rate
Signal type
Arrival type
Main St. SB Departure Link:
X1, Y1 coordinates
X2, Y2 coordinates
Traffic volume
Emission factor
Source height
Mixing zone width
10, 0(ft)
10, 1000 (ft)
1500 veh/hr
41.6g/veh-mi
Oft
40ft
-10, 1000 (ft)
-10, 0(ft)
1 200 veh/hr
41.6g/veh-mi (*)
Oft
40ft
-10, 10 (ft)
-10, 1000 (ft)
Oft
20ft
2
90s
40s
3s
1200 veh/hr
735.0 g/veh-hr (**)
1600 veh/hr/lane
1 (pretimed)
3 (average progression)
-10,0 (ft)
-10,-1000 (ft)
1200 veh/hr
41.6g/veh-mi (*)
Oft
40ft
45
-------
TABLE 3 (Continued)
Local St. Approach Link:
X1, Y1 coordinates
X2, Y2 coordinates
Traffic volume
Emission factor
Source height
Mixing zone width
Local St. Queue Link:
X1, Y1 coordinates
X2, Y2 coordinates
Source height
Mixing Zone Width
Number of travel lanes
Avg. signal cycle length
Avg. red time length
Clearance lost time
Approach traffic volume
Idle emission factor
Saturation flow rate
Signal type
Arrival rate
Local St. Departure Link:
X1, Y1 coordinates
X2, Y2 coordinates
Traffic volume
Emission factor
Source height
Mixing zone width
Site Meteorology
Wind speed
Wind direction
Stability class
Mixing height
Background concentrations
-1000,0 (ft)
0, 0 (ft)
1000 veh/hr
41.6g/veh-mi
Oft
40ft
-20, 0 (ft)
-1000,0 (ft)
Oft
20ft
2
90s
50s
3s
1000 veh/hr
735.0 g/veh-hr(**)
1600 veh/hr/lane
1 (pretimed)
3 (average progression)
0, 0 (ft)
1000,0 (ft)
1000 veh/hr
41.6g/veh-mi (*)
Oft
40ft
1 m/s
0°
4(D)
1000m
0.0 ppm
46
-------
TABLE 3 (Continued)
Site Meteorology (Continued)
Multiple wind directions = Yes
Wind direction increment angle = 10°
First increment multiplier = 0°
Last increment multiplier = 36
(*) Emission factor = 41.6 g/veh-mi, obtained from MOBILE 4.1 emission factor model,
assuming: average speed = 20 mph, Year 1990, ambient temperature = 30° F, default
for vehicle mix and thermal states, no I/M program, no ATP program, RVP = 11.5 psi,
and ASTM = C.
(**) Idle emission factor = 735.0 g/veh-hr obtained from MOBILE 4.1 emission factor model.
47
-------
INPUT EXAMPLE 1
'EXAMPLE - TWO WAY INTERSECTION (EX-1)' 60. 175. 0. 0. 8 0.3048 1 1
'REC 1 (SE CORNER)
'REC 2 (SW CORNER)
'REC 3 (NW CORNER)
'REC 4 (NE CORNER)
'REC 5 (E MID-MAIN) '
'REC 6 (W MID-MAIN) '
'REC 7 (N MID-LOCAL)'
'REC 8 (S MID-LOCAL)'
45.
-45.
-45.
45.
45.
-45.
-150.
-150.
ERSECTI
-35.
-35.
35.
35.
-150.
-150.
35.
-35.
ON'
6.0
6.0
6.0
6.0
6.0
6.0
6.0
6.0
910
'Main St.NB Appr. '
2
'Main St.NB Queue '
90 40
1
'Main St.NB Dep.
1
'Main St.SB Appr.
2
'Main St.SB Queue '
90 40
1
'Main St.SB Dep.
1
'Local St.Appr.Lnk.' 'AG' -1000.
2
'Local St.Queue Lnk.
'AG'
'AG'
'AG'
'AG'
'AG'
10. -
10.
3.0 1500
10.
-10.
-10.
1000.
-10.
735.0
0.
1000.
10.
10
10
1600
10
-10
-10
0.
. -1000.
1 3
. 1000.
0.
1000.
0. 1500. 41.6 0. 40.
0. 20.0 2
0. 1200. 41.6 0. 40,
0. 20.0 2
3.0 1200 735.0 1600 1 3
'AG'
-10.
0. -10. -1000. 1200. 41.6 0. 40,
0. 0. 0. 1000. 41.6 0. 40,
'AG'
-20.
0. -1000.
0.
0. 20.0
90
50
'Local St.Dep.Lnk.' 'AG' 0.
1.0 00. 4 1000. 0. 'Y' 10 0 36
3.0 1000 735.0 1600 1 3
0. 1000. 0. 1000. 41.6 0. 40,
48
-------
OUTPUT EXAMPLE 1 (Short Version)
CAL3QHC: LINE SOURCE DISPERSION MODEL - VERSION 2.0 Dated 95221
JOB: EXAMPLE - TWO WAY INTERSECTION (EX-1) RUN: MAIN ST. AND LOCAL ST. INTERSECTION
PAGE 1
DATE : 8/19/95
TIME : 16: 5:14
The MODE flag has been set to C for
SITE & METEOROLOGICAL VARIABLES
VS = .0 CM/S VD = .0 CM/S
U = 1.0 M/S CLAS = 4 (D)
LINK VARIABLES
LINK DESCRIPTION * LINK
* X1
1. Main St.NB 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. Lnk.
8. Local St. Queue Lnk.
10.0 -
10.0
10.0
-10.0
-10.0
-10.0
-1000.0
-20.0
9. Local St. Dep. Lnk. .0
calculating CO averages.
ZO
ATIM
= 175.
= 60.
COORDINATES (FT)
Y1
1000.0
-10.0
.0
1000.0
10.0
.0
.0
.0
.0
X2
10.0
10.0
10.0
-10.0
-10.0
-10.0
.0
-165.4
1000.0
CM
MINUTES
MIXH =
1000. M
* LENGTH BRG
Y2 * (FT)
.0 * 1000.
-238.5
1000.0
.0
141.2
-1000.0
.0
.0
.0
229.
1000.
1000.
131.
1000.
1000.
145.
1000.
(DEC)
360.
180.
360.
180.
360.
180.
90.
270.
90.
AMB =
TYPE
AG
AG
AG
AG
AG
AG
AG
AG
AG
VPH
1500.
1752.
1500.
1200.
1752.
1200.
1000.
2191.
1000.
.0 PPM
EF
(G/MI)
41.6
100.0
41.6
41.6
100.0
41.6
41.6
100.0
41.6
H U
(FT) (FT)
.0 40.0
.0 20.0
.0 40.0
.0 40.0
.0 20.0
.0 40.0
.0 40.0
.0 20.0
.0 40.0
V/C QUEUE
(VEH)
.94 11.6
.75 6.7
.80 7.4
-------
OUTPUT EXAMPLE 1 (Continued)
JOB: EXAMPLE - TWO WAY INTERSECTION (EX-1)
RUN: MAIN ST. AND LOCAL ST. INTERSECTION
PAGE 2
DATE : 8/19/95
TIME : 16: 5:14
ADDITIONAL QUEUE LINK PARAMETERS
LINK DESCRIPTION
2
5
8
. Main
. Main
. Local
RECEPTOR
St.NB Queue
St. SB Queue
St. Queue Lnk.
LOCATIONS
RECEPTOR
1.
2.
3.
4.
5.
6.
7.
8.
REC 1
REC 2
REC 3
REC 4
REC 5
REC 6
REC 7
REC 8
(SE CORNER)
(SW CORNER)
(NW CORNER)
(NE CORNER)
(E MID-MAIN)
(W MID-MAIN)
(N MID-LOCAL)
(S MID-LOCAL)
*
*
*
.*- .
*
*
*
*
*
*
*
*
*
*
*
*
CYCLE
LENGTH
(SEC)
90
90
90
RED CLEARANCE
TIME LOST TIME
(SEC) (SEC)
40 3.0
40 3.0
50 3.0
APPROACH SATURATION IDLE SIGNAL
COORDINATES (FT)
X
45
-45
-45
45
45
-45
-150
-150
.0
.0
.0
.0
.0
.0
.0
.0
Y Z
-35.0
-35.0
35.0
35.0
-150.0
-150.0
35.0
-35.0
6
6
6
6
6
6
6
6
VOL FLOW RATE EM FAC TYPE
(VPH) (VPH) (gm/hr)
1500 1600 735.00 1
1200 1600 735.00 1
1000 1600 735.00 1
*
*
.0 *
.0 *
.0 *
.0 *
.0 *
.0 *
.0 *
.0 *
ARRIVAL
RATE
3
3
3
50
-------
OUTPUT EXAMPLE 1 (Continued)
JOB: EXAMPLE - TWO WAY INTERSECTION (EX-1)
PAGE
RUN: MAIN ST. AND LOCAL ST. INTERSECTION
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.
WIND ANGLE RANGE: 0.-360.
WIND * CONCENTRATION
ANGLE * (PPM)
(DEGR)* REC1 REC2 REC3 REC4 REC5 REC6 REC7 REC8
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.
*
*
*
*
*
*
*
*
*
A
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
4.1
2.3
1.4
1.1
1.2
1.3
1.4
1.6
1.6
1.1
.5
.1
.0
.0
.0
.0
.4
1.5
4.1
6.6
7.8
7.7
7.4
6.8
6.4
6.4
7.5
9.2
10.7
10.8
9.9
8.6
7.9
7.4
7.0
5.9
4.1
9.3
11.3
11.6
10.1
8.3
6.6
6.0
6.1
6.4
6.2
5.8
5.3
5.5
5.6
6.1
6.3
6.1
5.0
2.9
1.1
.3
.0
.0
.0
.0
.1
.8
2.2
4.0
5.5
6.2
6.3
6.0
5.7
6.0
7.1
9.3
3.0
5.1
6.4
6.9
6.9
6.5
6.4
6.3
6.8
7.2
7.7
7.6
7.7
8.2
9.4
10.6
11.4
10.8
8.7
6.9
6.0
5.7
6.1
6.3
6.2
5.5
4.0
2.1
.8
.1
.0
.0
.0
.0
.3
1.2
3.0
2.6
1.0
.3
.0
.0
.0
.0
.1
.5
.1
.6
.6
.4
.3
.2
1.1
1.6
3.0
5.6
8.0
8.4
7.6
6.9
7.0
8.2
9.4
9.4
8.2
6.5
5.4
5.5
5.7
5.8
5.4
4.9
4.1
2.6
4.7
2.0
.7
.4
.5
.5
.5
.5
.4
.2
.0
.0
.0
.0
.0
.0
.3
1.1
2.9
4.8
6.1
6.7
7.0
6.6
6.4
6.2
6.2
6.4
6.6
7.0
7.6
8.4
9.4
9.8
9.3
7.7
4.7
5.5
6.7
6.9
6.9
6.3
6.1
6.0
5.7
5.7
5.4
5.3
5.2
5.5
5.4
5.2
4.9
4.4
3.6
2.3
1.0
.2
.0
.0
.0
.0
.0
.0
.2
.4
.5
.6
.9
1.4
1.8
2.4
3.4
5.5
.4
1.0
1.3
1.5
1.6
2.0
2.3
2.6
3.3
4.9
6.6
8.2
9.0
9.0
8.5
7.9
7.4
6.7
5.6
4.7
3.8
2.8
2.1
1.7
1.5
1.6
1.5
1.1
.5
.1
.0
.0
.0
.0
.0
.0
.4
5.6
6.6
7.2
7.6
8.3
8.9
9.0
8.1
6.4
4.7
3.2
2.6
2.6
2.6
2.2
1.8
1.4
1.0
.4
.0
.0
.0
.0
.0
.0
.1
.5
1.1
1.5
1.6
1.5
1.7
2.1
2.8
3.8
4.8
5.6
MAX * 10.8 11.6 11.4 9.4 9.8 6.9 9.0 9.0
DEGR. * 290 20 160 250 330 20 120 60
THE HIGHEST CONCENTRATION OF 11.60 PPM OCCURRED AT RECEPTOR REC2
51
-------
C-4 7, 305;i C4 7. 3053
REC 7
45 7,13 73
REC 3
C-1B 7.13 73
C-305
HEC a
C-45 7,-13 73
REC 1
C16 7, -13 73
REC 5
C16 7, -45 73
« 1
.1
-3 i;
CO
CO
R ?
K
. E
(
cu.
cc
D,
:> "
23
L^.
3 1
-3 1
C- 7 U^j
REC 4
C16 1, 13 73
e
V
jSU^L."0 LOCAL STREET \ \
^ >
-3-0 ^ S' C3D5'
C-4 7,-3053 C4 7, -3053
Figure 7. Example 2: Geometric configuration for a two-way multiphase intersection
(units in meters).
52
-------
TABLE 4
EXAMPLE - 2: Two-way Multiphase Signalized Intersection (Over-Capacity)
Input and output in meters
Description of Parameters:
Site Variables:
Averaging time (ATIM)
Surface roughness length (z0)
Settling velocity (Vs)
Deposition velocity (Vd)
Number of receptors
Scale conversion factor
60 min
175 cm
Ocm/s
0 cm/s
8
1.0 (units are in m)
Main St. NB Approach Link:
X1, Y1 coordinates
X2, Y2 coordinates
Traffic volume
Emission factor
Source height
Mixing zone width
Main St. NB Queue Link:
X1, Y1 coordinates
X2, Y2 coordinates
Source height
Mixing zone width
Number of travel lanes
Avg. signal cycle length
Avg. red time length
Clearance lost time
Approach traffic volume
Idle emission factor
Saturation flow rate
Signal type
Arrival rate
4.7, -305 (m)
4.7, 0 (m)
1730veh/hr
41.6g/veh-mi
0 m
12m
4.7, -6.2 (m)
4.7, -305 (m)
0 m
6.2m
2
90s
45s
2s
1500 veh/hr
720.0 g/veh-hr (««)
1700 veh/hr/lane
2 (actuated)
1 (worst progression)
53
-------
TABLE 4 (Continued)
Main St. NB Queue Left Turn:
X1, Y1 coordinates
X2, Y2 coordinates
Source height
Mixing zone width
Number of travel lanes
Avg. signal cycle length
Avg. red time length
Clearance lost time
Approach traffic volume
Idle emission factor
Saturation flow rate
Signal type
Arrival rate
0,-6.2 (m)
0, -60 (m)
0 m
3.1 m
1
90s
75s
2s
230 veh/hr
720.0 g/veh-hr(»»)
1400 veh/hr/lane
2 (actuated)
3 (average progression)
Main St. NB Departure Link:
X1, Y1 coordinates
X2, Y2 coordinates
Traffic volume
Emission factor
Source height
Mixing zone width
Main St. SB Approach Link:
X1, Y1 coordinates
X2, Y2 coordinates
Traffic volume
Emission factor
Source height
Mixing zone width
Main St. SB Queue Link:
X1, Y1 coordinates
X2, Y2 coordinates
Source height
Mixing zone width
Number of travel lanes
Avg. signal cycle length
Avg. red time length
4.7,0 (m)
4.7, 305 (m)
1500 veh/hr
41.6g/veh-mi(»)
0 m
12m
-4.7, 305 (m)
-4.7, 0 (m)
1950 veh/hr
41.6g/veh-mi (*)
0 m
12m
-4.7, 6.2 (m)
-4.7, 305 (m)
0 m
6.2m
2
90 sec
45 sec
54
-------
TABLE 4 (Continued)
Main St. SB Queue Link (Continued):
Clearance lost time
Approach traffic volume
Idle emission factor
Saturation flow rate
Signal type
Arrival rate
Main St. SB Queue Left Turn
X1, Y1 coordinates
X2, Y2 coordinates
Source height
Mixing zone width
Number of travel lanes
Avg. signal cycle length
Avg. red time length
Clearance lost time
Approach traffic volume
Idle emission factor
Saturation flow rate
Signal type
Arrival rate
Main St. SB Departure Link:
X1, Y1 coordinates
X2, Y2 coordinates
Traffic volume
Emission factor
Source height
Mixing zone width
Local St. EB Approach Link:
X1, Y1 coordinates
X2, Y2 coordinates
Traffic volume
Emission factor
Source height
Mixing zone width
2s
1750 veh/hr
720.0 g/veh-hrC*)
1800 veh/hr/lane
2 (actuated)
1 (worst progression)
0, 6.2 (m)
0, 60 (m)
0 m
3.1 (m)
1
90s
75s
2s
200 veh/hr
720.0 g/veh-hr (**)
1400 veh/hr/lane
2 (actuated)
3 (average progression)
-4.7, 0 (m)
-4.7, -305 (m)
1750 veh/hr
41.6 g/veh-mi
0 m
12m
-305,-3.1 (m)
0,-3.1 (m)
450 veh/hr
41.6 g/veh-mi (*)
0 m
12m
55
-------
TABLE 4 (Continued)
Local St. EB Queue Link:
XI, Y1 coordinates
X2, Y2 coordinates
Source height
Mixing zone width
Number of travel lanes
Avg. signal cycle length
Avg. red time length
Clearance lost time
Approach traffic Volume
Idle emission factor
Saturation flow rate
Signal type
Arrival rate
Local St. EB Departure Link:
X1, Y1 coordinates
X2, Y2 coordinates
Traffic volume
Emission factor
Source height
Mixing zone width
Local St. WB Approach Link:
X1,Y1 coordinates
X2, Y2 coordinates
Traffic volume
Emission factor
Source height
Mixing zone width
Local St. WB Queue Link:
X1, Y1 coordinates
X2, Y2 coordinates
Source height
Mixing zone width
Number of travel lanes
Avg. signal cycle length
Avg. red time length
-7.8,-3.1 (m)
-305,-3.1 (m)
0 m
6.2m
2
90s
60s
2s
450 veh/hr
720.0 g/veh-hr(*«)
1400veh/hr/lane
2 (actuated)
3 (average progression)
0,-3.1 (m)
305,-3.1 (m)
680 veh/hr
41.6g/veh-mi
0 m
12m
305,3.1 (m)
0, 3.1 (m)
510 veh/hr
41.6g/veh-mi (*)
0 m
12m
7.8,3.1 (m)
305,3.1 (m)
0 m
6.2m
2
90s
60s
56
-------
TABLE 4 (Continued)
Local St. WB Queue Link (Continued):
Clearance lost time = 2s
Approach traffic volume = 510veh/hr
Idle emission factor = 720.0 g/veh-hr (* *)
Saturation flow rate = 1400 veh/hr/lane
Signal type = 2 (actuated)
Arrival rate = 3 (average progression)
Local St. WB Departure Link:
X1, Y1 coordinates = 0, 3.1 (m)
X2, Y2 coordinates = -305, 3.1 (m)
Traffic volume = 710veh/hr
Emission factor = 41.6 g/veh-mi {*)
Source height = Om
Mixing zone width = 12m
Site Meteorology for wind angle range (150 to 210° in 5° increments)
Wind speed = 1 m/s
Wind direction = 0°
Stability class = 4 (D)
Mixing height = 1000m
Background concentrations = 0.0 ppm
Multiple wind directions = Yes
Wind direction increment angle = 5°
First increment multiplier = 30
Last increment multiplier = 42
Site Meteorology for wind angle range (240 to 300° in 3° increments)
Wind speed = 1 m/s
Wind direction = 0°
Stability class = 4 (D)
Mixing height = 1000m
Background concentrations = 0.0 ppm
Multiple wind directions = Yes
Wind direction increment angle = 3°
First increment multiplier = 80
Last increment multiplier = 100
57
-------
TABLE 4 (Continued)
Site Meteorology for wind angle range (330 to 70° [430°1 in 10° increments)
Wind speed = 2 m/s
Wind direction = 0°
Stability class = 4 (D)
Mixing height = 1000m
Background concentrations = 0.0 ppm
Multiple wind directions = Yes
Wind direction increment angle = 10°
First increment multiplier = 33
Last increment multiplier = 43
(*) Emission factor = 41.6 g/veh-mi, obtained from MOBILE 4.1 emission factor
model, assuming: average speed = 20 mph, Year 1990, ambient temperature
30°F, default for vehicle mix and thermal states, no I/M program, no ATP
program, RVP = 11.5 psi, and ASTM = C.
(**) Idle emission factor = 720.0 g/veh-hr obtained from the MOBILE 4.1 emission
factor model.
58
-------
INPUT EXAMPLE 2
'REC 1 (SE CORNER)
'REC 2 (SW CORNER)
'REC 3 (NW CORNER)
'REC 4 (NE CORNER)
'REC 5 (E MID-MAIN) '
'REC 6 (W MID-MAIN) '
'REC 7 (N MID-LOCAL)'
'REC 8 (S MID-LOCAL)'
'MAIN ST. AND LOCAL £
1
'Main St.NB Appr. '
2
'Main St.NB Queue '
90 45
2
'Main St.NB Q.Left'
90 75
1
'Main St.NB Dep.
1
'Main St.SB Appr. '
2
'Main St.SB Queue '
90 45
2
'Main St.SB Q.Left'
90 75
1
'Main St.SB Dep.
1
'Local St.EB Appr.'
2
'Local St.EB Queue'
90 60
1
'Local St.EB Dep. '
1
'Local St.WB Appr.'
2
'Local St.WB Queue'
90 60
1
'Local St.WB Dep. '
1.0 00. 4 1000. 0.
1.0 00. 4 1000. 0.
2.0 00. 4 1000. 0.
:PHASE INT. (Ex-2) ' so. 175
16.7 -13.7
-16.7 -13.7
-16.7 13.7
16.7 13.7
16.7 -45.7
-16.7 -45.7
-45.7 13.7
-45.7 -13.7
\ INTERSECTION'
/
/
1
t
1
t
1
f
t
t
1
t
t
1
AG'
AG'
AG'
AG'
AG'
AG'
AG'
AG'
AG'
AG'
AG'
AG'
AG'
AG'
Y' 5
Y' 3
Y' 10
2.0
2.0
-
_
2.0
2.0
-
4.7
4.7
1500
0.0
230
4.7
4.7
4.7
1750
0.0
200
4.7
-305.
_
2.0
7.8
450
0.
305.
2.0
30
80
33
7.8
510
0.
42
100
43
-305.
-6.2
720.0
-6.2
720.0
0.
305.
6.2
720.0
6.2
720.0
0.
-3.1
-3.1
720.0
-3.1
3.1
3.1
720.0
3.1
. 0
1.8
1.8
1.8
1.8
1.8
1.8
1.8
1.8
14 3 0
4.7
4.7
1700
0.0
1400
4.7
-4.7
-4.7
1800
0.0
1400
-4.7
0.
-305.
1400
305.
0.
305.
1400
-305.
. 0
. 8 1.0
0 0
'C'
0.
-305.
2 1
_
2 3
60.
305.
0.
305.
2 1
2 3
60.
-305.
-
.
2 3
-
2 3
3.1
3.1
3.1
3.1
3.1
3.1
1730.
0.
0.
1500.
1950.
0.
0.
1750.
450.
0.
680.
510.
0.
710.
41
6
3
41
41
6
3
41
41
6
41
41
6
41
.6
.2
.1
.6
.6
.2
.1
.6
.6
.2
.6
.6
.2
.6
0. 12
2
1
0. 12
0. 12
2
1
0. 12
0. 12
2
0. 12
0. 12
2
0. 12
59
-------
OUTPUT EXAMPLE 2 (Short Version)
CAL3QHC: LINE SOURCE DISPERSION MODEL - VERSION 2.0 Dated 95221
PAGE 1
JOB: EXAMPLE-TWO WAY MULTIPHASE INT.(EX-2)
RUN: MAIN ST. AND LOCAL ST. INTERSECTION
DATE : 8/23/95
TIME : 15:34:20
The MODE flag has been set to c for calculating CO averages.
SITE & METEOROLOGICAL VARIABLES
VS = .0 CM/S
U = 1.0 M/S
LINK VARIABLES
LINK DESCRIPTION
1. Main St.NB Appr.
2. Main St.NB Queue
3. Main St.NB Q.Left
4. Main St.NB Dep.
5. Main St. SB Appr.
6. Main St. SB Queue
7. Main St. SB Q.Left
8. Main St. SB Dep.
9. Local St.EB Appr.
10. Local St.EB Queue
11. Local St.EB Dep.
12. Local St.WB Appr.
13. Local St.WB Queue
U. Local St.WB Dep.
ADDITIONAL QUEUE LINK
LINK DESCRIPTION
2. Main St.NB Queue
3. Main St.NB Q.Left
6. Main St. SB Queue
7. Main St. SB Q.Left
10. Local St.EB Queue
13. Local St.WB Queue
VD = .0 CM/S ZO = 175. CM
CLAS = 4 (D) ATIM = 60. MINUTES
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
LINK COORDINATES (M)
X1
4.7
4.7
.0
4.7
-4.7
-4.7
.0
-4.7
-305.0
-7.8
.0
305.0
7.8
.0
Y1
-305.0
-6.2
-6.2
.0
305.0
6.2
6.2
.0
-3.1
-3.1
-3.1
3.1
3.1
3.1
X2
4.7
4.7
.0
4.7
-4.7
-4.7
.0
-4.7
.0
-30.3
305.0
.0
33.3
-305.0
*
Y2 *
.0 *
-100.5 *
-232.1 *
305.0 *
.0 *
294.8 *
135.7 *
-305.0 *
-3.1 *
-3.1 *
-3.1 *
3.1 *
3.1 *
3.1 *
MIXH = 1000. M AMB =
LENGTH
(M)
305.
94.
226.
305.
305.
289.
129.
305.
305.
23.
305.
305.
26.
305.
BRG TYPE
(DEC)
360. AG
180. AG
180. AG
360. AG
180. AG
360. AG
360. AG
180. AG
90. AG
270. AG
90. AG
270. AG
90. AG
270. AG
VPH
1730.
1931.
1609.
1500.
1950.
1931.
1609.
1750.
450.
2575.
680.
510.
2575.
710.
.0 PPM
EF
(G/MI)
41.6
100.0
100.0
41.6
41.6
100.0
100.0
41.6
41.6
100.0
41.6
41.6
100.0
41.6
H
(M)
.0
.0
.0
.0
.0
.0
.0
.0
.0
.0
.0
.0
.0
.0
w v/c
(M)
12.0
6.2 .97
3.1 1.35
12.0
12.0
6.2 1.07
3.1 1.17
12.0
12.0
6.2 .56
12.0
12.0
6.2 .63
12.0
QUEUE
(VEH)
15.7
37.6
48.1
21.6
3.8
4.3
PARAMETERS
*
*
*
CYCLE
LENGTH
(SEC)
90
90
90
90
90
90
RED
TIME
(SEC)
45
75
45
75
60
60
CLEARANCE
LOST TIME
(SEC)
2.0
2.0
2.0
2.0
2.0
2.0
APPROACH
VOL
(VPH)
1500
230
1750
200
450
510
SATURATION
FLOW RATE
(VPH)
1700
1400
1800
1400
1400
1400
IDLE
EM FAC
(gm/hr)
720.00
720.00
720.00
720.00
720.00
720.00
SIGNAL
TYPE
2
2
2
2
2
2
ARRIVAL
RATE
1
3
1
3
3
3
60
-------
JOB: EXAMPLE-TWO WAY MULTIPHASE INT.(EX-2)
OUTPUT EXAMPLE 2 (Continued)
RUN: MAIN ST. AND LOCAL ST. INTERSECTION
REMARKS : In search of the angle corresponding to
the maxirnun concentration, only the first
angle, of the angles with same maximum
concentrations, is indicated as maximum.
WIND ANGLE RANGE: 150.-210.
WIND
ANGLE
(DEGR)
150.
155.
160.
165.
170.
175.
180.
185.
190.
195.
200.
205.
CONCENTRATION
(PPM)
REC1
.0
.1
.4
1.0
2.2
4.0
6.1
8.2
9.9
10.9
11.3
11.3
210. * 10.9
MAX * 11.3
DEGR. * 200
REC2
9.3
9.5
9.3
9.0
7.8
6.4
4.7
3.1
1.6
.7
.3
.1
.0
9.5
155
REC3
11.8
12.7
13.3
13.6
13.1
11.9
10.2
8.6
6.9
5.9
5.3
4.7
4.2
13.6
165
REC4
6.5
6.8
7.2
7.7
9.0
11.0
13.0
14.9
16.2
16.5
15.8
14.8
13.7
16.5
195
REC5 REC6 REC7
.0
.1
.4
.9
1.9
3.2
5.1
7.1
8.6
10.0
10.6
10.7
10.6
10.7
205
8.7
8.7
8.5
7.9
6.9
5.5
4.0
2.7
1.5
.7
.3
.1
.0
8.7
150
6.5
6.0
5.4
4.6
3.9
2.9
2.1
1.7
1.4
1.2
1.2
1.2
1.2
6.5
150
REC8
4.0
3.8
3.4
2.8
2.1
1.4
.8
.4
.1
.0
.0
.0
.0
4.0
150
PAGE 2
DATE : 8/23/95
TIME : 15:34:20
RECEPTOR LOCATIONS
* COORDINATES
-------
JOB: EXAMPLE-TWO WAY MULTIPHASE INT.CEX-2)
MODEL RESULTS
OUTPUT EXAMPLE 2 (Continued)
RUN: MAIN ST. AND LOCAL ST. INTERSECTION
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.
WIND ANGLE RANGE: 240.-300.
WIND * CONCENTRATION
ANGLE * (PPM)
(DEGR)* REC1 REC2 REC3 REC4 REC5 REC6 REC7 REC8
240. <
243. <
246. <
249.
252.
255.
258.
261.
264.
267.
270.
273.
276.
279.
282.
285.
288.
291.
294.
297.
300.
MAX
DEGR.
* 9.0
» 8.9
» 8.9
9.0
8.9
9.3
9.4
9.6
9.9
10.4
10.7
11.1
11.4
11.4
11.5
11.7
11.6
11.0
10.7
10.5
10.1
11.7
285
.0 ;
.0
.0
.0
.1
.2
.3
.4
.6
.8
1.1
1.3
1.5
1.7
2.0
2.1
2.4
2.7
3.0
3.3
3.6
3.6 !
300 21
>.o
.9
.8
.7
.8
.7
.6
.6
.4
.3
.1
.9
.7
.5
.4
.3
.1
.1
.0
.0
.0
>.0
,0
9.0
8.9
9.0
9.3
9.3
9.3
9.2
9.0
9.0
8.9
8.6
8.4
8.2
7.9
7.9
7.7
7.5
7.7
7.6
7.7
7.8
9.3
249
9.0
8.9
8.9
8.9
8.7
8.9
8.8
8.8
8.7
8.9
8.9
8.9
9.0
9.1
9.2
9.2
9.4
9.4
9.6
9.7
9.8
9.8
300
.0
.0
.0
.0
.0
.0
.0
.0
.0
.2
.2
.2
.3
.4
.5
.5
.5
.5
.5
.5
.5
.5 1
282 25
.5
.6
.6
.6
.7
.6
.6
.5
.4
.2
.1
.8
_7
5
.4
.2
.1
.1
.0
.0
.0
.7 1
2 21
.0
.0
.0
.0
.1
.2
.3
.4
.6
.8
.0
.2
.2
.4
.4
.5
.5
.5
.5
.5
.4
.5
!5
PAGE 3
THE HIGHEST CONCENTRATION OF 11.70 PPM OCCURRED AT RECEPTOR REC1
62
-------
OUTPUT EXAMPLE 2 (Continued)
PAGE 4
JOB: EXAMPLE-TWO WAY MULTIPHASE INT.(EX-Z)
METEOROLOGICAL VARIABLES
U = 2.0 M/S CLAS = 4 (D) ATIM = 60. MINUTES
RUN: MAIN ST. AND LOCAL ST. INTERSECTION
MIXH = 1000. M AMB = .0 PPM
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.
WIND ANGLE RANGE: 330.-430.
WIND * CONCENTRATION
ANGLE * (PPM)
(DEGR)* REC1 REC2 REC3 REC4 REC5 REC6 REC7 REC8
330.
340.
350.
360.
10.
20.
30.
40.
50.
60.
70.
MAX
DEGR.
*
*
*
*
*
*
*
*
*
*
*
*
*
6.3
7.3
7.4
5.7
3.8
2.9
2.4
2.2
1.7
1.2
1.0
7.4
350
3.3
3.7
5.1
7.3
9.1
8.8
7.4
5.9
5.3
5.1
5.0
9.1
10
.0
.3
1.5
3.7
5.9
6.3
5.9
5.5
5.0
4.9
4.8
6.3
20
5.0
5.3
4.7
2.8
1.0
.2
.0
.0
.0
.0
.0
5.3
340
6.8
7.3
6.3
4.5
2.3
1.0
.5
.4
.3
.3
.3
7.3
340
.5
1.0
2.5
4.3
5.6
5.8
5.4
5.5
5.0
4.6
4.3
5.8
20
.0
.0
.1
.7
1.7
2.5
2.7
2.7
2.4
2.3
2.3
2.7
30
.6
.6
.7
1.4
2.5
3.2
3.5
3.8
4.0
4.6
4.6
4.6
60
THE HIGHEST CONCENTRATION OF 9.10 PPM OCCURRED AT RECEPTOR REC2
63
-------
(-60 20003
C-110, -703 |
REC 4
C-110 -2003 C.BD. -20003
CO,1 -2000)
Figure 8. Example 3: Geometric configuration for an urban highway (units are in
feet).
64
-------
TABLES
EXAMPLE - 3: Urban Highway
Description of Parameters:
Input and Output in meters
Site Variables:
Averaging Time (ATIM)
Surface roughness length (z0)
Settling velocity (V.)
Deposition velocity (Vd)
Number of receptors
Scale conversion factor
Northbound Link 1:
X1, Y1 coordinates
X2, Y2 coordinates
Traffic volume
Emission factor
Source height
Mixing zone width
Northbound Link 2:
X1, Y1 coordinates
X2, Y2 coordinates
Traffic volume
Emission factor
Source height
Mixing zone width
Exit Ramp Link 3:
X1, Y1 coordinates
X2, Y2 coordinates
Traffic volume
Emission factor
Source height
Mixing zone width
60 min
175 cm
0 cm/s
0 cm/s
4
0.3048 (units are in ft)
0, -2000 (ft)
0, -50 (ft)
5000 veh/hr
29.6g/veh-mi
Oft
60ft
0, -50 (ft)
0, 2000 (ft)
4000 veh/hr
29.6g/veh-mi (*)
Oft
60ft
0, -50 (ft)
70, 0 (ft)
1000 veh/hr
54.0g/veh-mi
Oft
40ft
65
-------
TABLE 5 (Continued)
Exit Ramp Link 4:
X1, Y1 coordinates
X2, Y2 coordinates
Traffic volume
Emission factor
Source height
Mixing zone width
Southbound Link 5:
X1, Y1 coordinates
X2, Y2 coordinates
Traffic volume
Emission factor
Source height
Mixing zone width
Site Meteorology
Wind speed
Wind direction
Stability class
Mixing height
Background concentrations
Multiple wind directions
Wind direction increment angle
First increment multiplier
Last increment multiplier
70, 0 (ft)
500, 0 (ft)
1000veh/hr
54.0 g/veh-mi (**)
Oft
40ft
-60, 2000 (ft)
-60, -2000 (ft)
5000 veh/hr
29.6 g/veh-mi (*)
Oft
60ft
1 m/s
0°
4(D)
1000m
0.0 ppm
Yes
10°
0
36
[*) Emission factor = 29.6 g/veh-mi, obtained from the MOBILE 4.1 emission factor
model, assuming: average speed = 55 mph. Year 1990, ambient temperature =
30°F, default for vehicle mix and thermal states, no I/M program, no ATP
program, RVP = 11.5 psi, and ASTM = C.
(**) Emission factor = 54.0 g/veh-mi, obtained from the MOBILE 4.1 emission factor
model, assuming: average speed = 15 mph. Year 1990, ambient temperature =
30°F, default for vehicle mix and thermal states, no I/M program, no ATP
program, RVP = 11.5 psi, and ASTM = C.
66
-------
INPUT EXAMPLE 3
'EXAMPLE - URBAN HIGHWAY (EX-3) ' 60. 175
'REC 1 (SE RAMP)' 50. -70
'REC 2 (SE) ' 50. -200
'REC 3 (SW) ' -110. -70
'REC 4 (SW) ' -110. -200
'URBAN HIGHWAY (FREE FLOW LINKS ONLY)'
1
' Northbound
1
' Northbound
1
' Exit Ramp
1
'Exit Ramp
1
' Southbound
1.0 00. 4
Lnk.
Lnk.
Lnk.
Lnk.
Lnk.
1000.
1'
2'
3'
4'
5'
0.
'AG'
'AG'
'AG'
'AG'
'AG'
'Y' 10
0.
0.
0.
70.
-60.
0 36
-2000.
-50.
-50.
0.
2000.
0. 0. 4 0.3048 0
6.0
6.0
6.0
6.0
5 1 1 ' c'
0.
0.
70.
500.
-60.
-50.
2000.
0.
0.
-2000.
5000.
4000.
1000.
1000.
5000.
29.6
29.6
54.0
54.0
29.6
0
0.
0.
0.
0.
0.
60
60
40
40
60
67
-------
OUTPUT EXAMPLE 3 (Long Version)
CAL30HC: LINE SOURCE DISPERSION MODEL - VERSION 2.0 Dated 95221
JOB: EXAMPLE - URBAN HIGHWAY (EX-3) RUN: URBAN HIGHWAY (FREE FLOW LINKS ONLY)
PAGE 1
DATE : 8/23/95
TIME : 15:35: 5
The MODE flag has been set to c
SITE & METEOROLOGICAL VARIABLES
VS = .0 CM/S
U = 1.0 M/S
LINK VARIABLES
LINK DESCRIPTION
1. Northbound Lnk.1
2. Northbound Lnk.2
3. Exit Ramp Lnk.3
4. Exit Ramp Lnk.4
5. Southbound Lnk.5
VD =
CLAS
*
*
*
*
*
*
*
*
.0
= 4
for calculating CO averages.
CM/S ZO
(D) ATIM
= 175.
= 60.
CM
MINUTES MIXH =
LINK COORDINATES (M)
X1
.0
.0
.0
21.3
-18.3
Y1
-609.6
-15.2
-15.2
.0
609.6
X2
.0
.0
21.3
152.4
-18.3
Y2
-15.2
609.6
.0
1000. M AMB =
LENGTH BRG TYPE
(M)
594.
625.
26.
.0 131.
-609.6 * 1219.
(DEG)
360. A6
360. AG
54. AG
90. AG
180. AG
VPH
5000.
4000.
1000.
1000.
5000.
.0 PPM
EF
(G/MI)
29.6
29.6
54.0
54.0
29.6
H W
(M) (M)
.0 18.3
.0 18.3
.0 12.2
.0 12.2
.0 18.3
V/C QUEUE
(VEH)
ftp
-------
OUTPUT EXAMPLE 3 (Continued)
PAGE 2
JOB: EXAMPLE - URBAN HIGHWAY (EX-3) RUN: URBAN HIGHWAY (FREE FLOW LINKS ONLY)
DATE : 8/23/95
TIME : 15:35: 5
ADDITIONAL QUEUE LINK PARAMETERS
LINK DESCRIPTION
*
*
*
. - .*. _
CYCLE
LENGTH
(SEC)
RED
TIME
(SEC)
CLEARANCE
LOST TIME
(SEC)
APPROACH
VOL
(VPH)
SATURATION
FLOW RATE
(VPH)
IDLE
EM FAC
(gm/hr)
SIGNAL
TYPE
ARRIVAL
RATE
RECEPTOR LOCATIONS
* COORDINATES (M)
RECEPTOR
1.
2.
3.
it.
REC
REC
REC
REC
1
2
3
4
(SE RAMP)
(SE)
(SW)
(SW)
*
*.
it
*
*
*
X
15
15
-33
-33
.2
.2
.5
.5
Y
-21
-61
-21
-61
.3
.0
.3
.0
Z
1.8
1.8
1.8
1.8
*
it
It
*
*
*
69
-------
OUTPUT EXAMPLE 3 (Continued)
PAGE 3
JOB: EXAMPLE - URBAN HIGHWAY (EX-3) RUN: URBAN HIGHWAY (FREE FLOW LINKS ONLY)
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.
WIND ANGLE RANGE: 0.-360.
WIND
ANGLE
* CONCENTRATION
* (PPM)
(DEGR)* REC1 REC2 REC3 REC4
4-
0.
10.
20.
30.
40.
50.
60.
70.
80.
90.
100.
110.
120.
130.
HO.
150.
160.
170.
180.
190.
200.
210.
220.
230.
240.
250.
260.
270.
280.
290.
300.
310.
320.
330.
340.
350.
360.
MAX
DEGR.
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
.*.
*
*
5.9
3.1
1.6
1.1
1.1
1.0
1.1
1.1
.8
.4
.1
.0
.0
.0
.0
.0
.5
2.1
5.3
7.8
8.0
7.3
6.6
6.1
5.8
5.6
5.8
5.7
6.0
6.0
6.2
6.5
6.9
7.4
8.0
8.0
5.9
8.0
200
5.4
2.4
.9
.5
.5
.5
.4
.2
.1
.0
.0
.0
.0
.0
.0
.0
.5
2.1
5.3
7.8
8.0
7.3
6.6
6.1
5.8
5.6
5.7
5.7
5.6
5.5
5.8
6.2
6.5
7.1
7.7
7.8
5.4
8.0
200
5.1
7.3
7.4
6.8
6.1
5.9
6.0
6.3
6.5
6.3
5.8
5.6
5.9
6.1
6.6
7.3
8.0
7.8
5.3
2.1
.5
.0
.0
.0
.0
.0
.0
.0
.0
.0
.0
.0
.0
.0
.5
2.0
5.1
8.0
160
5.1
7.5
7.6
7.2
6.9
6.7
6.4
5.9
5.8
5.7
5.7
5.6
5.8
6.1
6.6
7.3
8.0
7.8
5.2
2.1
.5
.0
.0
.0
.0
.0
.0
.0
.0
.0
.0
.0
.0
.0
.5
2.0
5.1
8.0
160
THE HIGHEST CONCENTRATION OF 8.00 PPM OCCURRED AT RECEPTOR REC3
70
-------
OUTPUT EXAMPLE 3 (Continued)
JOB: EXAMPLE - URBAN HIGHWAY (EX-3)
PAGE 4
RUN: URBAN HIGHWAY (FREE FLOW LINKS ONLY)
DATE
TIME
8/23/95
15:35: 5
RECEPTOR - LINK MATRIX FOR THE ANGLE PRODUCING
THE MAXIMUM CONCENTRATION FOR EACH RECEPTOR
* CO/LINK (PPM)
* ANGLE (DEGREES)
* REC1 REC2 REC3 REC4
LINK # * 200 200 160 160
1
2
3
4
5
*
*
*
*
*
5.2
.0
.0
.0
2.8
5.2
.0
.0
.0
2.8
2.8
.0
.0
.0
5.2
2.8
.0
.0
.0
5.2
71
-------
SECTION 5
SENSITIVITY ANALYSIS
5.1 OVERVIEW
The CAL3QHC model includes the CALlNE-3 line source dispersion model1 and a traffic
algorithm for estimating vehicular queue lengths at signalized intersections. Because
CAL3QHC includes CALINE3, the sensitivity analyses presented in the CALINE-3 manual
are directly applicable to CAL3QHC. The user should refer to the CALINE-3 manual for
discussion of the sensitivity of the model results with respect to: wind speed, atmospheric
stability, highway width, highway length, surface roughness, averaging time, deposition
velocity, settling velocity, wind angle, source height, mixing height, and median width.
Because its difference with the CALINE-3 model relates primarily to the handling of
vehicular queues, the two areas in which CAL3QHC warrants a separate sensitivity
discussion are: 1) the emission source strength of the vehicles in the queue, and 2) the
link length representing the number of vehicles in a queue. The variability of these two
parameters results in a nonlinear relationship between the source strengths and the
predicted concentrations -- as opposed to CALINE-3, where predicted concentrations are
directly proportional to source strengths. The three variables that directly affect the
calculation of vehicular queues are: signal timing, traffic volume on the queue link, and
number of traffic lanes in the queue link. To determine the effect of the variability of each
of these parameters on resultant pollutant levels, a series of model runs was performed in
which each of these three parameters were individually varied. The sensitivity runs were
performed for a single roadway segment representing two traffic lanes (each 10 feet wide)
with one receptor near the corner and one receptor at mid-block. Figure 9 shows the
configuration of the roadway segment and the variables used in the sensitivity run. Plots
were then completed depicting CO concentrations versus wind angle (with 180°
representing a parallel wind and 270° representing a crosswind).
73
-------
BEC 2
CMiD-BlOCO
PARALLEL
WIND
C1BO C3egr
-------
5.2 SIGNAL TIMING
Signal timing affects the computation in two ways. The emission source for the queue
links depends on both the idling emission factor and the fraction of red time (the larger the
fraction of red time, the stronger the emission source). In addition, the length of the queue
is determined by the volume to capacity ratio (V/C) of the approach link. Since the
capacity of the link is affected by the fraction of red time, the longer the red phase, the
smaller the available capacity, and the longer the queue length.
Three cases were analyzed: 30 percent red time, 40 percent red time, and 50 percent red
time. As seen in Figure 10, the increase in percent red time results in an increase of CO.
For the corner receptor the peak concentration, which occurs under a cross wind condition
in the case of 30 percent red (low V/C and short queues), shifts toward an almost parallel
wind condition for the 50 percent red case (higher V/C and longer queues). For the
midblock receptor, the CO increase is substantial when the length of the queue reaches the
midblock location.
5.3 TRAFFIC VOLUME ON THE QUEUE LINK
An increase in the traffic volume on an approach link will result in a longer queue length
but will not effect the strength of the emission source for the queue link. As explained in
Section 3.3.2, the strength of this line source is not dependent on the approach volume.
Three approach volumes were evaluated: 1000, 1500, and 2000 vehicles per hour (VPH).
As seen in Figure 11, an increase in traffic volume results in increased CO concentrations
and a shift in peak CO values from a cross wind situation, in the case of short queues, to a
parallel wind condition, as the queues get longer. For the midblock receptor, the CO
increase is substantial when the length of the queue reaches the midblock location.
75
-------
180 190 200 210 220 23D 240 250 260 270
Wind Angle
D 30* red time * 40% red time o 50* red time
Figure 10a. Variation of CO concentrations (ppm) at receptor 1 (corner) versus wind
angle for three different values of signal timing: 30% red time (V/C =
0.75, queue = 5.6 vehicles), 40% red time (V/C = 0.88, queue = 9.0
vehicles), and 50% red time (V/C = 1.08, queue = 42.9 vehicles).
180 190 200 210 220 230 240 250 260 270
Wind Angle C degrees^)
D 30% red time + 40% red time o 50« red time
Figure 10b. Same as Figure 10a except at receptor 2 (midblock)
76
-------
180 190 2QD 210 220 230 2-40 250 260 270
Wind Angie {cteQr*e&)
D 1DDD VP\-> + 1500 VPH o 2000 VPH
Figure 11a. Variation of CO concentrations (ppm) at receptor 1 (corner) versus wind
angle for three different values of approach traffic volume: 1000 vph
(V/C = 0.59, queue = 5.0 vehicles), 1500 vph (V/C = 0.88, queue =
9.0 vehicles), and 2000 vph (V/C = 1.18, queue = 93.5 vehicles).
180 190 200 ltd 220 230 240 250 2EO 270
wind Angle cdegrees}
D 1000 VPH + 1500 VPH o 2000 VPH
Figure 11 b.
Same as Figure 11a except at receptor 2 (mid-block).
77
-------
5.4 TRAFFIC LANES IN THE QUEUE LINK
The number of moving lanes affects the computations in two ways. First, the strength of
the emission source for a queue link is directly proportional to the number of moving lanes
(e.g. doubling the number of lanes at an intersection will double the source strength).
Second, the addition of lanes increases capacity. Thus by adding more available lanes
with the roadway traffic volume held constant, the length of the queue is shortened. The
net effect of these two components on CO concentrations is dependent on the wind angle
and the relative location of the receptor with respect to the intersection. An increase of
the number of available traffic lanes will not necessarily result in a reduction of predicted
CO concentration, since the strength of the line source will increase (more rows of idling
vehicles), but the queue will shorten (less vehicles queuing per lane). If the receptor is
very close to the intersection, with a larger number of lanes under cross-wind conditions,
higher CO levels may be predicted; but if the receptor is further away from the
intersection, a smaller number of lanes (a longer queue) under near parallel winds will result
in higher predicted CO levels. Two cases were analyzed for two and three traffic lanes for
the approach. As seen in Figure 12, even though the case with three traffic lanes has
more capacity and shorter queues compared with that of two traffic lanes, the cross wind
condition results in higher CO concentration at the corner receptor in the case of three
traffic lanes. For the midblock receptor, which is farther away from the intersection, two
traffic lanes (with the longer queues) result in higher CO concentrations.
5.5 TRAFFIC PARAMETERS
The three traffic parameters (Saturation Flow Rate, Signal Type, and Arrival Type) affect
the calculation of intersection capacity, delay, and queue length.
78
-------
190 200 210 220 230 240 250 260 270
Wind Angle ([degrees}
D 2 traffic lanes -*- 3 traffic lanes
Figure 12a. Variation of CO concentrations (ppm) at receptor 1 (corner) versus wind
angle for different number of traffic lanes: two traffic lanes (V/C = 0.88,
queue = 9.0 vehicles) and three traffic lanes (V/C = 0.59, queue = 5.0
vehicles).
180 190 200 210 220 230 240 250 260 270
wind Angle CdeoreesD
D 2 traffic lanes -f 3 traffic lanes
Figure 12b.
Same as Figure 12a except at receptor 2 (mid-block).
79
-------
Saturation flow rate is used in the calculation of intersection capacity and V/C ratio, having
a direct effect of the calculation of approach delay; the lower the saturation flow rate, the
higher the delay. Signal type and arrival type are used in the calculation of the progression
adjustment factor which has an effect on the approach delay but not on the V/C ratio; the
worst the progression, the higher the approach delay.
The effect of these parameters on the resulting CO concentrations is only significant when
the intersection operates at medium to high V/C ratios (near or over saturation conditions),
which are the conditions when higher delay results in longer queues and higher CO levels.
In the case of light traffic conditions (low V/C ratios), the change in approach delay has
minimum effect on the length of the queue and the resulting CO levels.
80
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SECTION 6
MODEL VALIDATION
6.1 OVERVIEW
The U.S. EPA completed the performance evaluation of eight intersection models in
simulating CO concentrations at the six intersections monitored as part of the Route 9A
Reconstruction Project in New York City2. The eight models evaluated included CAL3QHC
Version 2.0, FHWAINT14, GIM15, EPAINT14, CALIIME416, VOL9MOB4 (Volume 94 updated
with MOBILE4), TEXIN217, and IMM18. A complete phase I model evaluation study was
conducted using MOBILE4 emissions estimates. The phase I evaluation included all eight
intersection models at all six intersections. In late 1991, the MOBILE4.1 emissions model9,
an update to MOBILE4, was released. Thus, a phase II evaluation utilizing MOBILE4.1 was
conducted using a subset of the intersection models. Of the three EPA intersection models
(EPAINT, VOL9MOB4, and CAL3QHC), CAL3QHC performed best using MOBILE4. Of the
two models utilizing the FHWA advocated average speed approach rather than explicit
queuing (FHWAINT and GIM), GIM performed best. Therefore, the phase II MOBILE4.1
analysis was performed for the following five models: CAL3QHC, GIM, IMM, TEXIN2, and
CALINE4. When collecting and compiling the New York City database, the best quality
assurance procedures (e.g., analysis and comparison of collected data) were followed at
two of the six intersection sites. Site #1 (West/Chambers) and Site #2 (34th/8th). A
uniform wind analysis (e.g., similar wind speed and direction for different monitors at the
same intersection) conducted for each site indicated that Sites #5 (34th/12th) and #1 are
best in terms of unhindered approach wind flows and wind field uniformity. Thus, the
phase II MOBILE4.1 analysis was performed for the intersections at Sites #1, 2, and 5.
6.2 THE NEW YORK CITY DATABASE
A major air quality monitoring study was conducted in 1989-1990 in response to the
proposed reconstruction of a portion of Route 9A in New York City. As part of the
monitoring project, meteorological and CO air quality data were collected at two
background sites (Battery Park and Post Office) and six different intersections (Site #1
West/Chambers; #2 34th/8th; #3 65th/Broadway; #4 57th/7th; #5 34th/12th;#6
81
-------
Battery Tunnel). These sites are all located in midtown or lower Manhattan. The
meteorological data collected at each intersection included wind direction, wind speed,
temperature, and the fluctuation of the wind direction (sigma theta). These data were
measured at two towers per intersection except at site #2 where they were measured at
three towers. The meteorological measurements were taken at a height of 10 m ± 1 m.
In order to obtain detailed information concerning the traffic characteristics, a series of
video cameras were used to film the traffic at each site. Three months of continuous
traffic data were collected at each site producing approximately 13,000 hours of video
recordings. A limited number of videotaped hours from the Route 9A Study were
examined in order to obtain detailed information about the local traffic. The collected
traffic data were concurrent with the observed CO data. The examined traffic data are
comprised of the top 50 hours of CO concentrations observed for each of three months at
Sites #1 and 2 and the top 25 hours observed for each of three months at the remaining
sites.
All traffic data were obtained from videotapes except for the acceleration/deceleration
rates and the cruise speed. The acceleration/deceleration rates and cruise speeds were
obtained through the use of a vehicle outfitted with a travel-log machine that recorded
instantaneous speed versus time while traveling. Cruise speeds were taken directly from
the strip charts created in this way; acceleration/deceleration rates were determined from
the slope of the lines on the strip charts.
6.3 MODELING METHODOLOGY
The hourly averaged temperature data from the meteorological towers at each site were
averaged to calculate a site specific hourly value. For the remaining meteorological input
data, the meteorological tower closest to the CO monitor location was used. Mixing
heights of 1000 m were used, since the results are not affected if the mixing height is
between 100 and 1000 m high and mixing heights below 100 m in Manhattan do not
occur on a frequent basis.
The closest background concentration (Battery Park or the Post Office Station) was
82
-------
subtracted out of the observed concentration at each monitor. All modeling was
performed for one hour averages only. After the removal of the background
concentrations, a screening threshold of 0.5 ppm was used. When both the observed and
predicted concentrations at a monitor are less than 0.5 ppm that data pair was eliminated
from the data set.
A surface roughness length of 3.21 m was used for approach flows over numerous city
blocks. Lower values of the surface roughness length (0.03 m) were used at Site #5
(34th/12th) when the intersection was exposed to flows over the Hudson River without
intervening buildings. For modeling CO concentrations, the settling velocity and deposition
velocity were set at zero because CO is a gaseous emission. An averaging time of 60
minutes was used. Finally, a temperature-sensitive conversion of the modeled
concentrations from mg/m3 to parts per million (ppm) was conducted.
6.4 MODEL EVALUATION RESULTS
6.4.1 Regulatory Default Analysis
The ten hours with the highest observed concentrations were used to compare the
CAL3QHC predicted concentrations using the regulatory default meteorology to the
observed concentrations. The comparisons for each site are presented in Table 6. The
regulatory default meteorological conditions are defined as: Wind Speed = 1 m/s; Stability
Class = D; Sigma-Theta = 25°; Observed Temperature; and "Worst Case" Wind Direction
Angle (determined using ten degree increments).
At Site #1, the highest observed CO concentration of 10.6 ppm is nearly matched (10.4
ppm) by CAL3QHC unpaired in time or space. At Site #2, the maximum predicted
concentration by CAL3QHC of 8.0 ppm underpredicts the maximum observed
concentration of 11.5 ppm. Finally, at Site #5, the maximum observed concentration of
15.5 ppm is nearly matched by CAL3QHC which predicts 15.1 ppm.
6.4.2 Scoring Scheme Results
A method for aggregating component results of model performance (using the observed
meteorology) into a single performance measure19 was used to compare the overall
performance of the five models evaluated at three intersection sites. The bootstrap
83
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TABLE 6
COMPARISON OF TOP TEN OBSERVED CONCENTRATIONS WITH
CAL3QHC PREDICTED CONCENTRATIONS
Site
Observed
ppm
10.6
9.1
9.0
8.6
8.2
7.8
7.6
7.5
7.5
7.4
#1
Predicted
ppm
7.5
9.8
9.8
7.0
10.4
8.2
10.0
9.8
8.0
9.9
Site
Observed
ppm
11.5
10.5
10.4
10.2
10.2
9.1
8.8
8.5
8.4
8.3
#2
Predicted
ppm
5.4
8.0
7.0
6.9
3.9
4.7
4.9
7.3
6.7
6.1
Site
Observed
ppm
15.5
14.6
10.4
9.9
9.3
8.9
8.7
8.4
7.6
7.4
#5
Predicted
ppm
9.2
8.4
11.5
10.3
11.4
10.5
10.7
11.6
15.1
10.8
84
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re-sampling technique20 was used to determine the significance of differences in composite
performance between models.
The statistical analysis uses the robust highest concentration (RHC) for one-hour averages.
The RHC is based on a tail exponential fit to the upper end of the distribution and is calculated
as follows
RHC = x(n) + (x -
where x = average of the n-1 largest values
x(n) = nth largest value
n = number of values exceeding the threshold value (n = 26 or less)
The size of the three intersection data sets requires the value of n to be less than 26. The
value of n was nominally set to 1 1 so that the number of values averaged (x) was 10. In
general, the RHCs are largest using the operational (or entire) dataset for each site. When
calculating either the fractional bias (FB) or the absolute fractional bias (AFB),
AFB = \FB\ = 2
(OB - PR)
(OB + PR)
(6)
where OB and PR refer to the averages of the observed and predicted values, the RHC is used
rather than the mean of the highest 10 concentrations. The RHC is preferred in this type of
statistical evaluation because of its stability19. Also, the bootstrap distribution of the RHCs is
not artificially bounded at the maximum predicted or observed concentration, which allows for
a continuous range of concentrations.
When comparing these performance measures, one would like to know if differences are
significant. Simultaneous confidence intervals for each pair of models were calculated21 in
order to ensure an adequate confidence level and to protect against falsely concluding that two
models are different. A composite performance measure (CPM) is calculated for each model
as a weighted linear combination of the individual absolute fractional bias components. The
operational component is given a weight that is equal to the weight of the combined scientific
components. The scientific component refers to the evaluation of peak concentrations during
85
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specific meteorological conditions and the operational component refers to the evaluation of
peak averages independent of meteorological conditions. The results from the different data
bases (intersections) are given equal weight. The CPM is defined as
CPM = -AVG(AFB(i)) + -AFB(\) (7)
where AFB(i) = Absolute fractional bias weighted for each scientific category i,
AFB(1)= Absolute fractional bias for the operational one-hour averages.
The wind speed (u) < 6 mph and neutral/stable category is weighted more than the other two
categories because of the importance of this category for regulatory modeling purposes. Thus,
the average of AFB(i) is
AVG(AFB(i)) = 0.5 AFB(u * 6 mph, Neutral!'Stable) +
0.25 AFB(u <. 6 mph, Unstable) + <8>
0.25 AFB(u > 6 mph. All stabilities)
A combination of the CPM values across all three sites yields the composite model comparison
measure (CM). The CM results, shown in Figure 13, indicates that the best performing models
are CAL3QHC, TEXIN2, and CALINE4. Similarly, the AFB from scientific category 1 (u < 6
mph, neutral/stable) can also be combined over all three sites into a single model comparison
measure (CM). This category is typically most important in terms of regulatory applications. As
shown in Figure 14, CAL3QHC has the lowest CM by a factor of two.
86
-------
-1 D
0 B
0 6
0 4
T
D
CAL3QHC I MM4 TEX I N2 GIM CAL I NE-4
MODEL
Figure 13. The composite model comparison measure (CM) with 95% confidence limits using
CPM statistics.
87
-------
1 D
D a
0 6
i
n
T
t
0
T
i
U L
CAL3QHC I MM-4 TEX I N2 GIM CAL I NE4
MODEL
Figure 14. CM with 95% confidence limits using AFB of scientific category 1
88
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REFERENCES
1. Benson, P., CALINE-3 - A Versatile Dispersion Model for Predicting Air Pollutant Levels
Near Highways and Arterial Streets. Office of Transportation Laboratory, California DOT,
Sacramento, California. FHWA/CA/TL-79/23, Nov. 1979.
2. U.S. Environmental Protection Agency, Evaluation of CO Intersection Modeling
Techniques Using a New York Citv Database. U.S. EPA, OAQPS, Research Triangle Park,
North Carolina, EPA-454/R-92-004,1992.
3. Transportation Research Board (TRB), The Highway Capacity Manual. TRB Special
Report 209. Washington, D.C., 1985.
4. U.S. Environmental Protection Agency, Guidelines for Air Quality Maintenance Planning
and Analysis. Volume 9 (Revised): Evaluating indirect Sources. U.S. EPA Office of Air,
Noise and Radiation, Research Triangle Park, North Carolina. EPA-450/4-78-001-OAQPS
No.1.2-028R, 1979.
5. Newell G.F., Applications of Queuing Theory. 2nd edition, 1982.
6. Akcelik Rahmi, The Highway Capacity Manual Delay Formula for Signalized Intersections.
ITE Journal Volume 58 No 3, March 1988.
7. Webster F.B. and Cobee B.M., Traffic Signals - Road Research Technical Paper No 56.
Road Research Laboratory, 1966.
8. Webster F.B.. Traffic and Signal Settings - Road Research Technical Paper No 39. Road
Research Laboratory 1958.
9. U.S. Environmental Protection Agency, User's Guide to MOBILES (Mobile Source
Emissions Factor Model). U.S. EPA, Ann Arbor, Michigan, EPA-AA-AQAB-94-01,1994.
10. Randall, Patrick C. and Ng, Harrv N.C.. Air Quality Analysis Tools (AQAT-2). State of
California Air Resources Board, Technical Support Division, Sacramento, CA, 1987.
11. U.S. Environmental Protection Agency, User's Guide to PARTS: A Program for Calculating
Particulate Emissions from Motor Vehicles. U.S. EPA, Ann Arbor, Michigan, EPA-AA-
AQAB-94-02, 1995.
12. Institute of Transportation Engineers, Transportation and Traffic Engineering Handbook.
2nd edition, 1982.
89
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13. Wallace, C.E. et al, TRANSYT 7FF Traffic Network Study Tool Version 7F) - User's
Manual. University of Florida Transportation Research Center & Federal Highway
Administration, 1984.
14. PEL Development and Review of Traffic and CO Emission Components of Intersection
Modeling Techniques. U.S. EPA, Research Triangle Park, NC, 1988.
15. EMI Consultants, The Georgia Intersection Model for Air Quality Analysis. Knoxville, TN,
1985.
16. Benson. P.. CALINE4 - A Dispersion Model for Predicting Air Pollutant Concentrations
Near Roadways. Report No. FHWA/CA/TL-84/14. Office of Transportation Laboratory,
Sacramento, CA, 1989.
17. Bullin, G., J. Korpics, and M. Hlavinka, User's Guide to the TEXIN2/MOBILE4 Model.
Research Report 283-2. Texas State Department of Highways and Public Transportation,
College Station, TX, 1990.
18. NYDOT. Intersection Midblock Model User's Guide. New York State Department of
Transportation, Albany, NY, 1982.
19. Cox, W.M. and J.A. Tikvart, A Statistical Procedure for Determining the Best Performing
Air Quality Simulation Model. Atm. Env., 24. 2387-2395,1990.
20. Efron, B., The Jackknife. the Bootstrap and Other Resampling Plans. Society for
Industrial and Applied Mathematics, Philadelphia, PA, 1982.
21. Cleveland, W.S. and R. McGill, Graphical Perception: Theory, Experimentation, and
Application to the Development of Graphical Methods. J. Am. Stat. Assoc.. 79. 531-
554, 1984.
90
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TECHNICAL REPORT DATA
(Please read Instructions on reverse before completing)
1. REPORT NO.
EPA-454/R-92-006R
3. RECIPIENT'S ACCESSION NO.
4. TITLE AND SUBTITLE
User's Guide to CAL3QHC Version 2.0: A Modeling
Methodology for Predicting Pollutant Concentrations Near
Roadway Intersections (Revised)
5. REPORT DATE
September 1995
6. PERFORMING ORGANIZATION CODE
7. AUTHOR(S)
8. PERFORMING ORGANIZATION REPORT NO.
9. PERFORMING ORGANIZATION NAME AND ADDRESS
10. PROGRAM ELEMENT NO.
11. CONTRACT/GRANT NO.
12. SPONSORING AGENCY NAME AND ADDRESS
13. TYPE OF REPORT AND PERIOD COVERED
U.S. Environmental Protection Agency
Office of Air Quality Planning and Standards
Emissions, Monitoring, and Analysis Division
Research Triangle Park, NC 27711
14. SPONSORING AGENCY CODE
EPA/200/04
15. SUPPLEMENTARY NOTES
This document replaces EPA-454/R-92-006.
16. ABSTRACT
CAL3QHC is a microcomputer based model to predict carbon monoxide (CO) or other pollutant
concentrations from motor vehicles at roadway intersections. The model includes the CALINES
dispersion model along with a traffic algorithm to estimate vehicular queue lengths at signalized
intersections. CAL3QHC estimates total air pollutant concentrations from both moving and idling
vehicles. This document provides a technical description of the model, user instructions, and example
applications.
17.
KEY WORDS AND DOCUMENT ANALYSIS
DESCRIPTORS
b. IDENTIFIERS/OPEN ENDED TERMS
c. COSATI Field/Group
Carbon Monoxide (CO)
Intersection Modeling
CAL3QHC
Hot Spot Modeling
18. DISTRIBUTION STATEMENT
Release Unlimited
19. SECURITY CLASS (Report)
Unclassified
21. NO. OF PAGES
110
20. SECURITY CLASS (Page)
Unclassified
22. PRICE
EPA Form JJi6-l 0Uv. 4-77) pktVlous Ebitiort is OBSOLETE
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