svERA
United States
Environmental Protection
Agency
Office of Air Quality
Planning and Standards
Research Triangle Park NC 27711
EPA-450/3-78-033
August 1978
Air
Carbon Monoxide
Hot Spot
Guidelines
Volume I: Techniques
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EPA-450/3-78-033
Carbon Monoxide Hot Spot Guidelines
Volume I: Techniques
by
Theodore P. Midurski
GCA Corporation
GCA/Technology Division
Burlington Road
Bedford, Massachusetts 01730
Contract No. 68-02-2539
EPA Project Officer: George J. Schewe
Prepared for
U.S. ENVIRONMENTAL PROTECTION AGENCY
Office of Air, Noise, and Radiation
Office of Air Quality Planning and Standards
Research Triangle Park, North Carolina 27711
August 1978
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This report is issued by the Environmental Protection Agency to report
technical data of interest to a limited number of readers. Copies are
available free of charge to Federal employees, current contractors and
grantees, and nonprofit organizations - in limited quantities - from the
Library Services Office (MD-35), U.S. Environmental Protection Agency,
Research Triangle Park, North Carolina 27711; or, for a fee, from the
National Technical Information Service, 5285 Port Royal Road, Springfield,
Virginia 22161.
This report was furnished to the Environmental Protection Agency by
CCA Corporation, CCA/Technology Division, Burlington Rd., Bedford,
Massachusetts 01730, in fulfillment of Contract No. 68-02-2539. The
contents of this report are reproduced herein as received from CCA
Corporation, CCA/Technology Division. The opinions, findings, and
conclusions expressed are those of the author and not necessarily
those of the Environmental Protection Agency. Mention of company or
product names is not to be considered as an endorsement by the
Environmental Protection Agency.
Publication No. EPA-450/3-78-033
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ABSTRACT
This report presents guidelines for the identification and evaluation of
localized violations of carbon monoxide air quality standards (i.e., hot
spots) in the vicinity of streets and highways. These guidelines facili-
tate the rapid and efficient review of, carbon monoxide conditions asso-
ciated with existing urban street systems without the need for extensive
air quality monitoring. The procedures presented in the guidelines employ
traffic and roadway data in two stages of analysis. First, a screening
procedure is used to identify specific locations on the highway network
that have hot spot potential. This is followed by a verification proce-
dure, which provides a more detailed analysis of specific locations
(e.g., those identified by the screening procedure as having hot spot
potential). Both the screening and verification procedures utilize a
series of nomographs along with the various traffic and street data to
assess hot spot potential. The two procedures are performed manually and
are based on EPA's Guidelines for Evaluating Indirect Sources.
111
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PREFACE
This document is the first in a series comprising the Carbon Monoxide Hot
Spot Guidelines. The purpose of this series is to provide state and local
agencies with a relatively simple yet accurate procedure for assessing
carbon monoxide hot spot potential on urban street networks. Included
in the Hot Spot Guideline series are:
Volume I: Techniques
Volume II: Rationale
Volume III: Summary Workbook
Volume IV: Documentation of Computer Programs to Generate Volume I
Curves and Tables
Volume V: Intersection-Midblock Model User's Manual
Volume VI: Modified ISMAP User's Manual
Volume VII: Example Applications at Waltham/Providence/Washington, D.C.
Hot spots are defined as locations where ambient carbon monoxide concen-
trations exceed the national ambient air quality standards (NAAQS). For
both the 1-hour and 8-hour averaging times the assumption is made through-
out these guidelines that a CO hot spot is primarily affected by local
vehicle emissions, rather than areawide emissions. Studies have shown
that for the 1-hour CO concentration, local sources are the dominant
factor. Accordingly, representative urban worst-case meteorological,
traffic, and background concentration conditions are selected as those
corresponding to the period of maximum local emissions — usually the
period of peak traffic. For 8-hour concentrations evidence indicates
that neither the local nor the areawide contributions can be assumed to
be dominant in every case. However, for the purpose of analysis discussed
in these guidelines, local source domination of CO hot spots is assumed
v
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for 8-hour averages. This allows some consistency between assumptions in
relating the 1-hour and 8-hour CO estimates.
VI
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CONTENTS
Page
Abstract
Preface
List of Figures
List of Tables
Acknowledgments xv
Sections
I Introduction 1
A Purpose 1
B Overview of the Process for Control of Hot Spots 2
C Format of the Guidelines 5
II Overview of Mobile Source Carbon Monoxide Emissions and 8
Air Quality
A Introduction 8
B Background 8
C Concentration, Emissions, and Emission Sources 9
D Relationship Between Emissions and Resulting 31
Concentrations
E Determining the Critical Season 34
F Example 36
III Hot Spot Screening 41
A Introduction 41
B Overview of the Screening Procedure 46
C Detailed Instructions for Hot Spot Screening 58
D Methods of Estimating Roadway Capacity 70
E Example 95
IV Hot Spot Verification 98
A Introduction 98
B Overview of Hot Spot Verification 98
vii
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CONTENTS (continued)
Pase
C Worksheets and Instructions for Hot Spot 113
Verification
D Special Instructions 167
E Example 178
V Additional Information Regarding the Hot Spot 186
Guidelines
A Introduction 186
B Background CO Concentrations 186
C Evaluation Techniques for Determining the
Frequency of Exceeding NAAQS 192
VI Applications of the Hot Spot Guidelines 200
A Planning or Evaluation of Locations for 200
Ambient CO Monitoring
B Evaluating Areawide Control Measures 207
VII Evaluation of the Hot Spot Guidelines 210
A Evaluation 210
B Evaluation of the Verification Procedure 211
C Conclusion 217
VIII References 218
viii
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FIGURES
No. Page
1 Decisionmaking Process for Selecting CO control measures 3
2 General Concept of Relationship of Levels of Service to 20
operating Speed and Volume Capacity Ratio (not to scale)
3 Signal Timing and Phasing at Intersections 24
4 Representation of choke-on time as a function of 30
Temperature
5 Sketch of Lexington Street-School Street Intersection 37
6 Process Flow Diagram for the Screening of Carbon Monoxide 57
Hot Spots
7 Analysis at Signalized Intersections of a 2-lane, 2-way 73
Street and Various Cross Street Configurations in a
Congested Area
8 Analysis at Signalized Intersections of a 2-lane, 2-way 74
Street and Various Cross Street Configurations in a
Noncongested Area
9 Analysis at Signalized Intersections of a 3-lane, 2-way 75
street and Various Cross Street Configurations in a
congested area
10 Analysis at Signalized Intersections of a 3-lane, 2-way 76
Street and Various Cross Street Configurations in a
Noncongested Area
11 Analysis at Signalized Intersections of a 4-lane, 2-way 77
Street and Various Cross Street Configurations in a
Congested Area
12 Analysis at Signalized Intersections of a 4-lane, 2-way 78
Street and Various Cross Street Configurations in a
Noncongested area
IX
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FIGURES (continued)
No. Page
13 Analysis at Signalized Intersections of a 3-lane, 1-way 79
Street and Various Cross Street Configurations
14 Analysis at Signalized Intersections of a 3-lane, 1-way 80
Street and Various Cross Street Configurations for Non-
congested Areas
15 Analysis of Signalized Intersections of a 2-lane, 1-way 81
Street and Various Cross Street Configurations
16 Analysis at Signalized Intersections for a 2-lane, 1-way 82
Street and Various Cross Street Configurations in Non-
congested Areas
17 Analysis for Uninterrupted Flow Conditions of Controlled 83
Access Facilities (Expressways) for Various Lane
Configurations
18 Analysis for Uninterrupted Flow Conditions of Uncon- 84
trolled Access Facilities (Arterials) for Various Lane
Configurations
19 Analysis at Nonsignalized Intersections of a 2-lane, 85
2-way Controlled Street Intersecting a 2-lane, 2-way
or 2-lane, 1-way Major Street in a Congested Area
20 Analysis at Nonsignalized Intersections of a 2-lane, 86
2-way Controlled Street Intersecting a 2-lane, 2-way
or 2-lane, 1-way major Street in a Noncongested Area
21 Analysis at Nonsignalized Intersections of a 2-lane, 87
2-way Controlled Street Intersecting a 4-lane, 2-way
Major Street in a Congested Area
22 Analysis at Nonsignalized Intersections of a 2-lane, 88
2-way Controlled Street Intersecting a 4-lane, 2-way
Major Street in a Noncongested Area
23 Analysis at Nonsignalized Intersections of a 4-lane, 89
2-way Controlled Street Intersecting a 4-lane, 2-way
Major Street in a Congested Area
24 Analysis at Nonsignalized Intersections of a 4-lane, 90
2-way Controlled Street Intersecting a 4-lane, 2-way
Major Street in a Noncongested Area
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FIGURES (continued)
No. Page
25 Analysis at Nonsignalized Intersections of a 2-lane, 91
1-way Controlled Street Intersecting a 2-lane, 2-way
or 2-lane, 1-way Major Street
26 Analysis at Nonsignalized Intersections of a 2-lane, 92
1-way Controlled Street Intersecting a 2-lane, 2-way or
2-lane, 1-way Major Street in a Noncongested Area
27 Analysis at Nonsignalized Intersections of a 2-lane, 93
1-way Controlled Street Intersecting a 4-lane,, 2-way
Major Street
28 Analysis at Nonsignalized Intersections of a 2-lane, 94
1-way Controlled Street Intersecting a 4-lane, 2-way
Major Street in a Noncongested Area
29 Example Screening 96
30 Schematic of Cross-Street Circulation Between Buildings 104
31 Normalized CO Concentration Contribution from Excess 160
Emissions on Approach 1 as a Function of Queue Length
on Approach 1 for Intersections
32 Normalized CO Concentration Contributions from Excess 161
Emissions on Approaches 2, 3 and 4 as a function of
Queue Length on Approach 1 for Intersections
33 Normalized CO Concentration Contribution at each Traffic 162
Stream at Locations of Uninterrupted Flow
34 Normalized CO Concentration Contributions from Free-Flow 163
Emissions on each Lane of Roadways at Intersections
35 Normalized CO Concentration in Street-Canyons Assuming 164
Vortex Has Formed
36 Distance Correction Factor for Excess Emission Contrib- 165
utions at Intersections
37 Distance Correction Factor for Free-Flow Emission 166
Contributions at Intersection Locations
38 CO Concentration Contribution from Excess Emissions on 1.69
Approach 1 as a function of Number of Lanes and Queue
Length
xi
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FIGURES (continued)
No.
39 Typical Relationships Between Average Lane Volume and 175
Average Speed in One Direction of Travel on Controlled
Access Expressways Under Uninterrupted Flow Conditions
40 Typical Relationships Between Average Lane Volume and 176
Average Speed in One Direction of Travel on Multilane
Rural Highways Under Uninterrupted Flow Conditions
41 Example Hot Spot Verification 179
42 approach Orientation and Receptor (R) Location 182
43 Lines of Constant Emission Rate Yielding Violations 197
of the 8-hr CO Standard as a Function of Windspeed
and Wind Angle
Xll
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TABLES
No. Page
1 Important Features of Traffic Signal Installations 25
with Regard to the Impact on Traffic Operation
2 Traffic Characteristics of Example Intersection 38
3 Signal Phasing and Timing at Example Intersection 39
4 Emission Correction Factor Characteristics of 39
Example Intersection
5 Summary of Data Requirements for Hot Spot Screening 48
6 Combined Effect of Lane Width and Restricted Lateral 71
Clearance on Capacity and Service Volumes of Divided
Freeways and Expressways and Two-Lane Highways with
Uninterrupted Flow
7 Average Generalized Adjustment Factors for Trucks on 72
Freeways and Expressways, and 2-lane Highways over
Extended Section Lengths
8 Summary of Data Requirements for Hot Spot Verification 100
9 Total Queue Emissions, (QQT)> Cruise Component Emission, 128
(Qqc) » anc* Queue Length as a Function of Major and Cross-
Street Volumes and Cruise Speed - Signalized Intersections
10 Free Flow Emission Rate Qf, in Grams per Meter-Second as 142
a Function of Lane Volume and Vehicle Speed on Roadways
11 Total Queue Emissions, (QQf), Cruise Component Emission, 143
(QQC), and Queue Length as a Function of Major and Cross-
Street Volumes and Cruise Speed - Unsignalized Inter-
sections
12 Emission Correction Factors for Region, Calendar Year, 157
Speed, Percent Cold Starts (H) and Temperature (T) by
Vehicle Type
13 Criteria for Selection of Cruise Speed Values for Urban 177
Roadways and Intersections
xiii
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TABLES (continued)
No. Page
14 Areal Averaged Normalized Concentration (SEC/M) — 190
D Stability
15 Areal Averaged Normalized Concentration (SEC/M) — 191
E Stability
16 Assumed Probabilities of Hourly Windspeed/Wind Angle 198
Combinations Occurring at the Lexington Street -
School Street Intersection
17 Hypothetical Example Tabulation of Calculated CO Levels 205
18 Case I: Results of the Verification at Signalized 213
Intersections
19 Case II: Results of the Verification Procedure at 215
Uninterrupted Flow Locations
20 Observed Versus Estimated 1 Hour CO Concentrations, at 216
Intersection of Illinois Route 83 and Twenty-Second
Street, Oakbrook, Illinois
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ACKNOWLEDGMENTS
We wish to acknowledge the significant contributions made early in the
development of the Hot Spot Guidelines by previous GCA/Technology Division.
staff members, including Dr. Robert Patterson, Messrs. David Bryant,
Alan Castaline, and Walter Stanley. We are especially indebted to the
EPA Project Officer, Mr. George J. Schewe of the Source Receptor Analysis
Branch, who provided overall project direction and performed extensive
technical and editorial review of the final reports.
xv
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Errata for EPA-450/3-78-033
Carbon Monoxide Hot Spot Guidelines
Volume I: Techniques
1. Pages 83-84. The abscissa is in "hundreds" of vehicles.
2. Pages 96-97. All references to Figure "7B" should be "7D."
3. Page 157-159. Replace all of Table 12 with the attached Table 12.
4. Page 180. Step 16 should be Step 17, Step 17 should be Step 18,
Step 18 should be Step 19, and Step 19 should be Step 16.
5. Page 180-181. Correct the following steps in the work sheet to
reflect corrected numerical values:
Step 13
Step 14a
Step 14b
Step 15
Step 16
Step 17
Step 20
Step 21
Step 22
Step 23
Step 24
Step 25
Step 26
1.15 1.15
3.6
0.7
4.3
0.82 0.82
0.0159
6.4 1.9
9.2
13.5
9.5
2.9
12.4
10.8
1.15 1.15
0.82 0.82
0.6 0.3
6. Page 183. Line 6, change 2.85 to 1.41. The equation given for C£f
should read:
CEf = (0.78)(0.83) + (0.11)0-41) + (0.06)(5.23) + (0.05)(0.6) = 1.15
In the numerical solution for Xf . and X. ^nc.c the emission correction
r 9 iiid in T 9 ci OSs
factor should be changed from 1.33 to 1.15, thus yielding concentration
3 3
estimates of 3.6 mg/m and 0.7 mg/m respectively. The total concentration
then, Xf, should be 3.6 + 0.7 = 4.3 mg/m .
-------
7. Page 184. First paragraph, the excess emissions correction factor
should be 0.82.
The numerical solution for Qg should be:
(0.02297)(0.82) - [0.00251)(1.15) = 0.0159
8. Page 185. All concentrations given are incorrect and corrections
are here given by line number.
3
Line 1 9.2 mg/m
3
Line 3 4.3 + 9.2 = 13.5 mg/m
3
Line 4 13.5 mg/m
3 3
Line 6 9.5 mg/m ,9.5 mg/m
3
Line 9 12.4 mg/m
3
Line 10 12.4 mg/m , 10.8 ppm
3
Line 15 12.4 mg/m , 10.8 ppm
9. Page 14, point d., second line, "vehicle" is mispelled.
10. Page 44, third paragraph, second line, "and" should be "an."
11. Page 112, second paragraph, lines 10 and 11, "ration" should be
"ratios."
12. Page 173, points (a) and (b) reference to Table 8 should be Table 9,
and Figure 33 should be Figure 38.
13. Page 199. First line, "Hozworth21" should be "Holzworth22"
Assumption 4, last line, "mexiing" should be "mixino"
Last paragraph, third line, chanae "in assumption 5" to
"above"
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**LDV-light duty vehicles, LDT-light duty trucks, MC-motorcycles, HDG-heavy duty gas trucks,
HDD-heavy duty diesel.
Table 12. Emission correction factors for region, calendar year, speed, percent
cold starts (C), percent hot starts(H), and temperature (T) by
vehicle type (M).
27
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' LD V-light duty vehicles, LDT-light duty trucks, MC-motorcycles, HDG-heavy duty gas trucks,
HDD-neavy-duty diesel.
Table 12. (Continued)
-------
of,
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YT4R:
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T
10 60
10 30
35 60
35 80
6(J 60
60 30
10 60
10 30
3* 60
35 30
60 60
60 30
10 60
1 0 80
35 60
35 an
6'0 60
60 3n
i
1 .07.
1.37
1 .5»
7.6'*
?.14
1 .55
1.43
2.67
3.79
3.H5
.75
.35
I .58
I .26
2.27
1 .66
to/a
30
.96
.92
1.37
.77
.74
.52
.34
.27
.93
. /'J
2.57
2. 1 4
.79
. 74
1 .07
.35
1 .25
. 96
5.77
.57
1978
45
u
1.04
2. 01
1 .68
2.07
2.32
1 . = 6
1.4?
2.P4
2. 36
4. 1 2
1..M
1 .04
.74
1 . /S
1 .39
2.4*
1 ,83
1978
45
.98
.91
1 -45
I .28
1 ,?2
I .64
1 . 12
1 .75
2.02
1 .77
?.. 72
2.79
."6
.31
1.12
.91
I . 33
1 .06
7.04
. = a
| 0 q 1
n
.7"
. 69
1 . 1 0
,96
1 .47
1 .72
1.41
1 .12
2.21
1.97
3.05
2.^2
.56
.50
.09
.77
1 .4?
1 .04
I 9an
0
.60
.64
.85
.77
t .03
.00
1 .25
1.71
I .6*
1.53
2.11
1 .35
.45
.47
.61
.49
. 76
.56
1.33
.0 1
1 OH-"!
1 <=•
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.76
1 . ^ 1
1.14
1 .84
1 .5?
1 .35
1 .76
7.20
1.89
3.o<;
7.51
.69
.61
1.71
.94
1 .73
1 .76
|08H
t 5
.72
.69
1 .01
- 7 1
1 . 10
1.13
1.19
1 . 1 5
I .66
1 .50
7-11
1.8S
.5*
.5 1
.74
. 60
.71
.68
5.17
.6 1
[
-------
TM.
Y r i o ;
5 P f. E n ;
u n v 20 10 20
20 10 '«o
20 35 70
20 35 4 C
20 6H 20
20 60 40
L-M 20 10 20
20 10 40
20 35 20
7n 35 40
20 60 7"
2n 60 4n
*C 2n 10 20
20 10 40
20 35 7?
20 35 40
20 60 20
20 60 40
YE»*:
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« "i c r •
1.1V 20 10 6Q
20 in a 7
0
. 1 1
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. 31
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. 74
.6V
1.37
1.16
1.91
1.61
. 70
. 1 /
. 37
.2*
.55
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1947
30
. 33
. 37
.57
.53
. 3 1
. 73
. 66
.63
I .05
.97
I . 44
1 . 30
. 15
. I 4
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. 1 7
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4,00
.52
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45
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. 37
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. 60
1.19
1 . 0 I
.75
.70
1 .«*?
1 . 74
7.01
I . 71
. 20
. 1 7
. 40
.30
. 60
.43
1 9?7
4C
.35
.34
.62
.57
.P9
. 30
.67
. A4
1.12
1.02
1 . 56
1.41
. 15
. 1 4
.73
. 1 1
.3 I
. 77
5.01
. =0
1 990
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.06
. 1 I
. 1 0
. 1 6
. 1 3
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. 17
.3.1
.24
1 090
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.05
.09
.08
. 1 7
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.63
.58
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. 7 7
. I 0
.09
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. 10
. I 7
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[ o n n
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. ? I
. 79
.59
.57
.37
.75
.r-c
.5?
.97
.16
1 .3o
I . 70
. t 3
. 1 t
. 24
. 1 «
.34
.2S
I 090
15
.27
.26
. 47
.43
. 66
.60
.50
. 4fl
.73
.73
1.07
.97
. 1 o
.09
. 1 4
. 1 1
. 1 a
. 1 T
7 . 4Q
. 59
1 ""0
30
. 3"
. 37
.67
.53
.99
.35
.59
.55
I .03
.9%
1.51
1 . 36
. t 3
. I 7
.76
.20
. 39
.23
1 990
30
. 30
.29
.52
. 4fl
.75
.61
.53
.5 i
. a*
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1.09
. to
.09
. 1 5
. I 2
.20
. 1 4
1.27
-=•?
1 090
4<;
. 36
. 33
,73
.61
I .09
- 9 3
.61
.57
1.17
1 .07
1.77
1 .43
, 1 4
. I 7
.23
.2 1
.H3
.3"
1 990
4C
.31
. 30
.57
.52
.3?
.74
.54
.5?
.93
.as
1 .31
1.19
. 10
.09
. 1 6
. 1 7
.71
. 1 5
4.1!
. SCI
**t_DV-iight duty vehicles, LDT-light duty trucks, MC-motorcycles, HDG-heavy duty gas trucks,
HDD-heavy duty aiesel.
Table 12. (Continued)
-------
I SS I iiM rnoor<-Tln» p-^rr^S cnis rjrr, JO
YF A3 ; | 97 8
s p e r. n : o
1978
(5
i 9/fl
30
1978
"5
1 9ao 1 '
n
'80
1 5
1980 1 9 ,1 0 |
10 45
oq 2
(J
1 987
15
1 9^7
JO
1 "82
45
I "> V 20 in 20 1.04 I,71 2 . 1 3 .'.44 .85 I . «* A 1.7*, i • 9 p .AS I , n 7 ! . 2 A 1 . «f>
20 10 40 .93 t.=A l.<»3 7.72 .7A 1.30 1.5" 1.78 . 5 * .96 1,13 1.76
2 n 35 2P 1.84 7.94 3.48 }.9i 1.53 7 , 5 A 7.99 3,3-, [,|9 1.87 2.17 7.40
20 3<\ HO i.i+ft 7.3« 2.79 l.m 1.7| 7.m 2.3<; 2.A7 ,74 1.47 1.71 (.90
20 60 7.n 7.A5 4.|A 4 . ? 1 5,18 7..?? 3.A1". '4.2? 4.A" 1.73 2.A7 1. n 7 J.^O
20 60 40 7.0? 3.M 3.6
20 10 40 1.79 2.01 2.SS 2.77 I . 5 A 1.33 7.2" 7.A3 1 . 10 1 , A 8 7."1* 2.11
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20 35 4n 7.7A 7.9fl 3.^9 4.n7 7.39 2.71 3.7A 3.Afl 2.00 7.S3 7.99 3.14
20 AO 70 4.fl| c.nfl =,. *2 A.At H.is 4.7^ 5.5T A. 17 3.51 4 . 5 8
1 .A 1
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nor;
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AO
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1
7
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1.17
. 9 7
1 . 45
1.1"
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1 .0 I
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1.71
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1.37
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1.19
1 .37
1 .67
I .-I
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9 . ua
1 . 1.1 o
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1 .00
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1.31
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7.29
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1 .20
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1.17
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1 . 1 1
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t .21"!
9.70
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. AA
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1.16
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1.31
•9<=
0 . I 5
.a 7
h*LDV-light duty vehicles, LDT-light duty trucks, MC-motorcycles, HDG-oeavy duty gas trucks,
HDD-heavy duty diesel.
Table 12. (Continued)
-------
?«
21
2n
21
2n
20
L,r 2n
21
20
2"
21
20
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21
21
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1.17 ( . ri / 1.3? 7."[ . T -4 l.M |.M |,HW
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a |5 311 145 n ic in
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.52 .6" .AM .75 . "7 . "A .57 .57
.47 . 6 •» ,A7 ,*n .43 .47 ,4fl .c,^
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.>i4 .71 .31 ,a<» .AO . « 7 .6^ »72
,A9 .9/ 1.15 I.?7 .46 .70 . 3 •> .90
.AA .91 l.|0 |.22 . 't* ,A7 .73 ,3A
-•»« 1.32 1.51 1,70 -A3 .^^ I. in i.2i
. * * 1.17 i . •» A 1 . C | . S 7 .AS . 9 rt ;..17
1.22 |.A« 1.77 2.12 «aO i.21 1.33 |.57
I .fl«4 I . » 1 1.6.7 1.3n . «9 I.H7 1.17 1.29
.11 »[A .2! t?e, .34 .10 .11 .IA
.ln . 1 "* . l ^ .7} .15 .11 .1? . t '»
. ! A .72 .77 .31 .19 ,|4 ,|7 .20
.12 « ' 7 ,?2 .75 . n 7 ,M .1-4 . 1 A
.71 .7° .T* ,]i .17 .M .21 .74
• 15 .7'' .74 .79 . n a ,i7 .15 . ; T
«.o7 A . ; I 7 . » 1 I . fl ? ^.77 5.1! s.75 i . A 2 i.n7
jV-ugnt dur/ venicies, 'JjT-iignt ciur/ tracks, MC-motorcvcles, HCQ-heavy cur/ gas :rjc!
-------
SECTION I
INTRODUCTION
A. PURPOSE
This volume presents a set of guidelines for the identification and analysis
of carbon monoxide "hot spots," which are defined as locations where ambient
carbon monoxide concentrations may exceed the national ambient air quality
standards (NAAQS). The guidelines are intended for engineers, planners,
and others who must consider the air quality effects of traffic management
decisions and who are responsible for traffic planning to control CO hot
spots. The guidelines present a screening procedure to identify potential
carbon monoxide hot spots using only data on automobile traffic volumes,
thus obviating time-consuming and costly monitoring of air quality at
potential hot spots.
The guidelines also present a hot spot verification procedure that uses
more detailed traffic and roadway data to estimate maximum carbon monoxide
concentrations at specific locations. The following text discusses in
detail the concepts of hot spot screening and verification, and presents
the analytical techniques and procedures, as well.
-------
3. OVERVIEW OF THE PROCESS FOR CONTROL OF HOT SPOTS
1. General
Controlling CO hot spots requires (1) the screening of the entire highway
network to identify specific locations that are potential hot spots, (2)
the detailed analysis of each potential hot spot, and (3) the evaluation,
selection, and implementation of control measures. Although these guide-
lines are primarily concerned with identification and analysis of carbon
monoxide problem areas, their ultimate purpose is to allow the selection
of suitable control measures to insure the NAAQS for CO.
Choosing among alternative traffic measures for CO hot spot control is
much like other public investment decisions. One must balance the benefits
and costs an choose accordingly. When the goal is to meet air quality
standards, the nature of the choice is somewhat altered because attainment
is necessary to protect public health. Consequently, meeting air qualify
standards should be the first consideration when selecting among alternative
actions for control of hot spots. Once that criterion has been satisfied,
then the choice among alternatives can be made on the basis of costs and
other issues, as with other public investments.
2. Recommended Process
figure 1 is a flow diagram depicting the overall process for selecting CO
control measures. Each of the numbered steps will be briefly described.
a. Step 1: Screening - Screening of roadways and intersections to identify
potential CO hot spots is the first task. Screening procedures; presented
in Section III of this volume, use generalized procedures and a minimum
amount of traffic data; available data can be used in most cases. To
facilitate the rapid screening of many locations, simple charts and nomo-
graphs are provided. The output is the identification of potential hot
spots; no quantitative estimates of CO concentrations are produced.,
-------
0
®
1
I
L.
! i
i
i_
SCREENING
VERIFICATION
DETAILED
MODELING
©
i
IDENTIFIC
ALTERh
IMPROV
i
ATION OF
JATIVE
EMENTS
EVALUATION OF
ALTERNATIVES
<
, SELECTION OF
CONTROL MEASURES
\
IMPLEMENTATION
1
EVALUATION
• >
AVAILABLE TRAFFIC DATA
LIMITED ADDITIONAL
TRAFFIC. DATA
COLLECT NEW
TRAFFIC DATA,
AIR QUALITY DATA,
METEOROLOGICAL DATA
OBTAIN
TRANSPORTATION
PLANNING DATA
AIR QUALITY EFFECTS
SOCIAL, ECONOMIC
INSTITUTIONAL, OTHER
EFFECTS
- — e
1
1
1
1
1
1
H
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
I
1
1
1
1
1
1
i
i
i
- j
HOT SPOT
GUIDELINES
MODELS ON OTHER
DECISION BY
STATE/REGIONAL
I POLICY-MAKERS
HOT SPOT GUIDELINES
AND SUPPLEMENTAL
MODELS
Figure 1. Decisionmaking process for selecting
CO control measures
-------
b. Step . 2: Verification - Verification involves more detailed analysis
of locations that are shown by screening to be potential hot spots. Veri-
fication uses a larger amount of site-specific data than does screening,
and produces quantative estimates of CO levels. New traffic data may be
needed in many instances. Section IV of this volume describes the pro-
cedures for verification.
c. Step 3: Detailed Modeling - Once potential hot spots have been identi-
fied, a higher level of analysis can be conducted utilizing computer models
such as the Intersection - Midblock Model, Modified ISMAP, CALINE 2, etc.,
or, in some instances, the Indirect Source Guidelines. Generally, these
models require significantly more data than do the Hot Spot Guidelines.
In order to utilize the various models to their fullest, detailed traffic,
emission, and meteorological data for the site being studied should be
available.
d. Step 4: Identification of Alternative Improvements - Knowing the
amount of CO emissions reduction that is needed, the planner can begin to
narrow the choice of control measures by identifying those alternatives
that appear capable of meeting the air quality requirements. New (or
existing) transportation planning data are obtained at this point, to
allow forecasting emissions for future years and to allow consideration of
macroscale traffic changes when necessary. The alternatives to be evalu-
ated should be capable of achieving the required reduction in emissions
at each hot spot, after accounting for other mitigating factors such as
new vehicle pollution control devices.
e. Step 5: Evaluation of Alternatives - Evaluation of air quality effects
uses the models from Step 3 and determines whether the required reductions
would be met. For those alternative measures that would satisfy the air
quality criteria (only), the other effects are then identified and quanti-
fied. If the alternative control measures are inadequate, or if it is
-------
prudent to examine additional alternatives because of implementation
obstacles that may arise, the process would revert to Step 4 at this point.
f. Step 6: Selection of Control Measures - Selecting among the alternative
measures requires balancing the nonair quality effects (assuming that only
those measures that will achieve the required reductions are being con-
sidered at this point). The thrust of the choice is to minimize the
adverse impacts. Often, however, the choice will require weighing effects
of various types. For example, the decision might be between two control
measures that are similar except that one requires more capital outlay but
is more beneficial to fuel consumption. Such choices are commonly made in
transporation facility planning. These guidelines cannot detail how to
make such choices; an excellent summary of the process has been pub-
lished1 and includes a recommended procedure for considering nonmonetary
cost and benefits.
g. Step 7: Implementation - Having selected a measure, it must be imple-
mented. When planning for implementation of specific measures, the time to
accomplish this step should be -considered in all analyses of effectiveness.
h. Step 8: Evaluation - After implementation, the traffic and air quality
should be monitored and calculations made to determine if the required
reductions in concentrations are being achieved. Rarely are planning
predictions exact; in some cases it will be necessary to adjust or supple-
ment the control measures either to meet air quality goals or to ameliorate
unexpected impacts.
C. FORMAT OF THE GUIDELINES
It is envisioned that the guidelines will be used by a wide range of
individuals, some of whom may not be familiar with various traffic engineer-
ing and meteorological concepts. This being the case, it is appropriate
that an overview of the technical aspects of traffic on streets and
-------
highways, emissions from motor vehicles, meteorological effects, and the
interrelationships that exist among these, be provided; this overview is
presented in Section II. The actual discussion of the analytical techniques
begins in Section III where the screening techniques are presented.
Section IV continues the presentation of the Guidelines procedures with a
discussion of the verification process. A more detailed discussion of
several technical issues mentioned in Sections II, III, and IV is provided
in Section V. This Section also provides guidance for the user in selecting
several variables that are used at various points in the guidelines pro-
cedures. Two specific applications of the guidelines are discussed in
Section VI. Specifically, this section considers applying the guidelines
first as a method for evaluating the placement of an air quality monitor
with regard to the likelihood of it measuring peak carbon monoxide con-
centrations, and second in the context of carbon monoxide control plan
development. The final section, Section VII, presents discussion of the
results of a validation study conducted to evaluate the consistency and
reasonableness of the guidelines.
Several related documents have been prepared, as well. Volume II2 of the
hot spot guidelines provides a detailed discussion of the rationale behind
Q
the guidelines discussed in this document. Volume III provides a summary
of the basic elements from this volume that are required to perform hot
spot analyses. Its purpose is to serve as a workbook for those involved
in applying these techniques in urban hot spot analyses. Volume IV in
this series describes a procedure that can be used to update the Guidelines
to account for revisions in mobile source emission factors that may occur
in the future. Volume IV, then, is not designed for use by the user of
the basic Guidelines. Volumes V5 and VI6 are user's manuals for computer
models that expand the scope of the Guidelines significantly. These models
- the Intersection-Midblock Model and the Modified ISMAP Model - enable the
analyst to perform very detailed studies of carbon monoxide levels using
specific meteorological and emission source parameters. Finally, Vol-
ume VII describes the application of the Guidelines in the analysis of
hot spot potential in Waltham, Massachusetts and Washington, D.C. , and
-------
reports a demonstration of using the Guidelines as a tool for evaluating
the impact of a revised traffic circulation plan in Providence, Rhode
Island, on local carbon monoxide concentrations.
-------
SECTION II
OVERVIEW OF MOBILE SOURCE CARBON MONOXIDE
EMISSIONS AND AIR QUALITY
A. INTRODUCTION
This section provides an overview of a number of fundamental issues con-
cerning carbon monoxide, it sources, and its impact on air quality. The
purpose of this section is to provide those users who do not have at
least basic familiarity with various concepts of emission characteristics,
traffic engineering, or meteorology, with an indication of the interrelation-
ships that exist among these parameters and how these ultimately affect
air quality. Individuals who have a working knowledge of various air
quality concepts may choose to skip this section.
B. BACKGROUND
Carbon monoxide is a colorless, odorless, tasteless, relatively inert gas
that is formed principally as a by-product of incomplete combustion. The
dominant source of carbon monoxide emissions is the internal combustion
engine. In fact, it has been estimated that some 76 percent of the total
carbon monoxide emissions that occurred in the United States during 1972
were directly attributable to transportation sources associated with the
internal combustion engine.
Because deleterious effects are associated with exposure of humans to
carbon monoxide, efforts are being made to reduce, where necessary, high
ambient carbon monoxide concentrations. In this regard, the federal Clean
Air Act of 1970 was enacted as a mechanism for establishing specific limits
8
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for ambient concentrations of carbon monoxide, and for providing the legal
mandates to ensure that efforts would be expended by state and local
governments to meet these limits. These limits, the NAAQS, are that 1-hour
average ambient concentration of CO must not exceed 40 mg/m^ (35 ppm) more
than once a year, and that 8-hour average concentrations must not exceed
10 mg/m (9 ppm) more than once per year during nonoverlapping periods.x
Experience has shown that the 8-hour standard is the more often violated.
Because carbon monoxide is a primary product of combustion, relatively
inert, and released near the ground, the highest ambient concentrations
are typically found in the immediate vicinity of the emission source.
Hence, studies of carbon monoxide problems must focus on local analyses
rather than areawide analyses of the type undertaken for other pollutants
like oxidants and S02. The highest concentrations are also most likely
to be found at locations with the highest emission rates. In this regard,
the locations of most interest for hot spot analysis are near points of
heavy traffic flow or traffic congestion.
C. CONCENTRATION, EMISSIONS, and EMISSION SOURCES
1. Concentrations
Analyses of CO hot spots focus primarily on determining the magnitude of
ambient concentrations that can be expected to occur at a specified loca-
tion, and relating this concentration to a corresponding standard. In
this connection, then, it is necessary to understand the factors that
directly affect concentrations in the general vicinity of an emissions
source.
Nonoverlapping in this case implies that there are no common 1-hour time
increments included in two or more 8-hour averaging periods. Thus, for a
period of, say, 16 hours, there are a total of nine continuous 8-hour
periods; however, only two of these periods- the first hour through the
eighth hour, and the ninth hour through the sixteenth hour- are nonoverlapping.
-------
A very basic concept is that a concentration is a relative quantity; in
hot spot analyses, it is the quantity of carbon monoxide relative to a
quantity of ambient air. This is usually expressed in mass per volume or
in parts (of carbon monoxide) per million (parts of ambient air). The
concentration of carbon monoxide occurring at any point is primarily a
function of three determinants including (1) the rate that the carbon
monoxide is discharged into the ambient air by various sources; (2) the
forces that act to disperse, dilute, or transport the carbon monoxide once
it is emitted into the ambient air; and (3) the orientation of the point
of interest with respect to the primary emission source(s).
Carbon monoxide concentrations occurring in the immediate vicinity of a
street or highway are generally considered to be comprised of two com-
ponents, including (1) a concentration directly attributable to the nearby
roadway, and (3) a background component that is attributable to all
other emission sources. This can be represented by the equation:
where XT = the total concentration of carbon monoxide occurring at
a given location
XR = the component attributable to nearby sources
X,, = the background component.
B
The first component, Xr,» is a function of several variables and can be
K
expressed by the equation:
XR - V • E • K • 1/u (2)
where V = traffic volume (in vehicles per day);
E = average emission rate (in grams per vehicle-mile)
for all vehicles comprising V;
10
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K = Proportionality factor that accounts for factors such
as the orientation of the point of interest with
respect to the source, and other factors that determine
the dispersion characteristics; and
u = wind speed.
It can be seen from Equation 2 that at a given location, XT. *-s
K
directly proportional to both traffic volume and emission rate, and in-
versely proportional to wind speed. The determinants of XD will be dis-
ix
cussed in detail in a subsequent portion of this section.
The second component of XT ls tne background concentration, XB« Background
concentration can be defined as an ambient concentration occurring as a
result of the areawide (extraurban plus intraurban) diffusion of carbon
monoxide from all sources. Background concentrations are generally con-
sidered to be more or less uniform throughout large areas of similar
development intensity (i.e., areas such as metropolitan core area, sub-
urban areas, rural areas, etc.). Analyses of air quality modeling data re-
flecting 1974 conditions for large metropolitan areas such as Boston and
Springfield, Massachusetts, indicate background concentrations in the range of
2.9 to 5.9 mg/m3 averaged over a 1-hour period. Normalizing this to 1982
conditions results in a range of 1.7 to 2.9 mg/m3.
In most instances where carbon monoxide concentrations are high enough to
warrant concern, it has been found that the roadway component, x > is
R
generally substantially more important than the background component. Con-
sequently, the procedures presented in this document focus primarily on
estimating the roadway component, XT,* and then adding a measured or assumed
K
background component to the computed roadway component to derive an estimate
of the total concentration. A methodology for estimating area-specific
background concentration is provided, however, in Section V.B, and this
may be used when the requisite data are available.
11
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2, Emissions and Emission Sources
It was indicated that the primary concern here is with emissions of carbon
monoxide from highway traffic. The amount of carbon monoxide emitted from
traffic is directly proportional to the number of vehicles in the traffic
stream. There are, however, a number of other factors that also affect
the amount of any contaminant produced for a given volume of traffic, and
these factors are discussed in the following paragraphs.
a. Dimensioning Emissions - In order to provide a quantitative parameter
with which to analyze carbon monoxide problems, emissions from any source
are generally described in terms of an emissions rate. Two emlss'lon rates
are of importance in hot spot analyses—these describe the amount of carbon
monoxide (in grams) emitted either for given units of distance and time
(meters, seconds), or for a specific unit of time (usually 1 second).
Ordinarily, the emission rate of a moving vehicle is described in either
grams per mile or grams per kilometer while for an idling vehicle, grams
per minute is commonly used.
b. Emission Rates - The actual emission rate for any vehicle.varies
widely according to two primary factors including (1) the operational char-
acteristics of the vehicle such as travel speed, acceleration rate, etc.,
and (2) environmental conditions such as ambient temperature or altitude.
In order to provide a tractable method for estimating the quantity of
emissions produced from vehicular traffic, the entire vehicle population is
distributed among six general categories, each of which displays unique
emission characteristics, and use is made of composite emission rate for
all vehicles in each category. This rate is based on a typical driving
cycle and accounts for emission variability due to operational and environ-
mental conditions. The individual categories include:
# light-duty, gasoline-powered vehicles - LDV (passenger cars)
• light-duty, gasoline-powered trucks - LOT (trucks up to
8,500 pounds gross vehicle weight)
12
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• heavy-duty, gasoline-powered vehicles - HDV-G (vehicles over
8,500 pounds gross vehicle weight)
• light-duty, diesel-powered vehicles - LDV-D
• heavy-duty, diesel-powered vehicles - HDV-D
• motorcycles - MC
The four categories involving gasoline-powered vehicles are each subdivided
further. This subcategorization is based on (1) engine design (four-cycle
or two-cycle operation) for motorcycles only, and (2) model year for the
other three categories. Model year distribution is important because emis-
sion control devices differ in design and effectiveness by model year.
Also,' most emission control devices tend to become less effective with time
in use, therefore vehicle emission rates will generally increase with
accumulated mileage (mileage correlates very well statistically with vehi-
cle age). Diesel-powered vehicles generally display a rather uniform carbon
monoxide emission rate that tends to be substantially lower than a gasoline
engine of corresponding size and rating; hence, additional carbon monoxide
emission control devices have not been required on these types of vehicles.
Owing to these factors, there is no real need to consider emission rates
separately by model year for diesel-powered vehicles.
Large-scale testing by the U.S. Environmental Protection Agency of vehicles
in each category (and model-year subcategory) has resulted in the defini-
tion of composite emission rate for each vehicle category. The composite
emission rate implicitly reflects a specific set of prevailing operational
and environmental conditions. The emission rates that are most widely used
in the analysis of carbon monoxide emissions generated by motor vehicles
are those developed by the U.S. Environmental Protection Agency and re-
ported in Automobile Exhaust Emission Modal Analysis Model and MOBILE I.®
These documents describe both the implicit operating and environmental
conditions, and methods for adjusting the emission rates to reflect other
operational and environmental characteristics. The reader should refer
to these two reports for details.
13
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c. Emission Factors - An emission faator is the average emission rate
(gm/km) for all vehicles within a specific subcategory (vehicle type by
model year, or engine type for motorcycles) that reflects specific operat-
ing and environmental conditions.
A composite emission factor is the average emission rate for all vehicles
within one of the six vehicle-type categories, or all categories combined,
that reflects specific operating and environmental conditions, and has
been weighted according to a particular distribution of model-year vehicles
within the category or categories.
d. Emission Quantities - The quantity of carbon monoxide emitted by an
individual vehcle is a function of the emission rate (expressed as an
emission factor) and an operating time or distance parameter (minutes,
seconds, miles, or kilometers). In considering a finite section of roadway,
then, the quantity of carbon monoxide produced during a given time period
(say, 24-hours) can be expressed as:
Q = d
(nLDv)+ (CLDT (nLDT) + (CroV-G) (nHDV-G) + (CHDV-D) (nHDV-D)
(CLDV-D)(nLDV-D) +
where
Q
d
C'
(3)
the total emissions produced, grams;
the length of the section, kilometers;
composite emission factor for light-duty vehicles, gm/km;
C' = composite emission factor for light-duty trucks, gm/km;
J-iU -L
C'
HD V — G
composite emission factor for heavy-duty, gasoline-
, / .
powered trucks, gm/km;
composite emission factor for heavy-duty, diesel-
powered trucks, gm/km;
-------
C' „ _ = composite emission factor for light-duty, diesel-
powered vehicles, gm/km;
C' = composite emission factor for motorcycles, gm/km;
n._v • the number of light-duty vehicles traversing the
section during 24 hours;
nT_T = the number of light-duty trucks traversing the
section during 24 hours;
nurw /^ a tne number of heavy-duty trucks traversing the
HDV—G .1 . . -/ ,
section during 24 hours;
n = the number of heavy-duty, diesel-powered trucks
traversing the section during 24 hours;
nLDV-D = the number of light-duty, diesel-powered vehicles
traversing the section during 24 hours; and
n.,- = the number of motorcycles traversing the section
during 24 hours;
Two emission quantities are important in considering carbon monoxide con-
centrations on highway systems. The first - fvee flow emissions - is de-
fined as the quantity of emissions produced during a specified time-period
by vehicles that are (assumed to be) traveling at a relatively constant,
though not necessarily uniform, rate without interruptions. The second
quantity - excess emissions - is defined as the quantity of emissions
above the cruise emissions component produced during a specified time-
period by vehicles during acceleration, deceleration, and idling modes.
It should be apparent then, that free flow emissions are of the greatest
interest when considering carbon monoxide emissions resulting from high-
ways or street sections where traffic flows fairly smoothly without
interruption. On the other hand, where interruptions are expected and
do occur (for instance at intersections) both free flow and excess emis-
sions are important. It should be noted that the largest portion of
the total emission generated at signalized intersections is often asso-
ciated with the excess emissions from accelerating, decelerating, and
idling vehicles.
15
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The CO emission factors assumed in deriving Figures 7 through 28 in the
next section were obtained by using the emission factor information for
a national average mix of vehicles (by model year) derived from MOBILE I8
for the calendar year 1982 and speed correction factors from the same
reference. It was assumed that 20 percent of these vehicles are operat-
ing from a cold start and approximately 88 percent of the vehicle mile-
age is attributable to light-duty vehicles, 8 percent is the result of
light-duty trucks, and 4 percent from heavy-duty vehicles.
The emission factors used in deriving Figures 7 through 28 were estimated
using the Automobile Exhaust Emission Modal Analysis Model. Combinations
of vehicle operating modes used in the model were similar to observed traffic
in the vicinity of a signalized intersection. Since the Automobile Exhaust
Emission Modal Analysis Model assumes that there are no vehicles operating
from a cold start, a correction factor was applied to the estimates obtained
with the model to reflect an assumption of 20 percent cold starts. This was
done so that all the curves in Section III reflect consistent assumptions
about the percentage of cold starts. The ambient temperature was assumed
to be 0°C.
3. Emission Source Considerations
It was indicated previously that the rate at which carbon monoxide is
generated from a motor vehicle is primarily a function of the operating
characteristics of the vehicle and the prevailing environmental conditions.
These two parameters, which are fundamental in any analysis of highway-
generated emissions, are discussed in detail here.
a. Operational and Environmental Aspects of Traffic - In this context,
operational aspects include the mode of operation - accelerating, deceler-
ating, idling, or cruising, and the rates thereof. Environmental aspects
include two categories; traffic environment and atmospheric environment;
the interest at this point is with the traffic environment.
16
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Design speed is a speed selected for purposes of design and correlation of
those features of a highway, such as curvature, superelevation, and sight
distance, upon which the safe operation of vehicles is dependent. Average
highway speed is the weighted average of the design speeds within a high-
way section, when each subsection within the section is considered to have
an individual design speed. Cruise speed or operating speed is the highest
overall speed at which a driver can travel on a given highway under favor-
able weather conditions and under prevailing traffic conditions without at
any time exceeding the safe speed as determined by the design speed on a
section-by-section basis.
The interrelationship among traffic operating parameters, traffic environ-
ment, and emissions produced is quite complex. In this relationship the
quantity of emissions produced is directly related to traffic operating
parameters such as cruise speed or idling time. In turn, the traffic envi-
ronment to a large degree determines the operating characteristics for any
given roadway. Several of the most important elements of the traffic envi-
ronment include the physical features of the roadway, the density and
composition of traffic, and the geographic location of the facility.
Perhaps the most important manifestation of the various elements of the
traffic environment is that collectively they determine the roadway's ca-
pacity, which (as will be demonstrated later) is one of the two parameters
that directly affects roadway operating characteristics. Roadway capacity
is a fundamental topic in the traffic engineering field, and it has been
the subject of much research over the past years. Perhaps the most com-
prehensive documentation of the topic is the Highway Research Board's
1965 Highway Capacity Manual.9
Highway capacity can be defined as the rate of traffic flow (usually in
vehicles per hour) that can be accommodated.under certain defined conditions,
Note that the definition of capacity involves both a rate of traffic flow
and a specific set of conditions. These specific conditions, referred to
as prevailing conditions, include two general categories - prevailing
17
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roadway conditions, and prevailing traffic conditions. Prevailing roadway
conditions are those established by the physical features of the roadway
and are therefore relatively fixed or constant with respect to short time
intervals; these include items such as the number of lanes available,
topographic characteristics, and the presence of flow constraints such as
narrow bridges or traffic signals. Prevailing traffic conditions are those
that.depend on the nature of traffic using the roadway, and therefore, can
and do change from hour-to-hour; examples include the relative number of
cars, trucks, and buses in the vehicle stream, and the density of traffic
on the facility. Prevailing conditions can be described also in terms of
level of service. Level of service is a term used to indicate the quali-
tative aspects of traffic flow. Considered in level of service are a number
of factors including speed, traffic interruptions, freedom to maneuver,
safety, driving comfort and convenience, and operating cost. In practice,
six levels of service are used to describe the qualitative aspects of
traffic on street sections that are not influenced by intersections; these
various levels of service are described in the Highway Capacity Manual^
as follows:
Level of service A describes a condition of free flow, with low
volumes and high speeds. Traffic density is low, with speeds
controlled by driver desires, speed limits, and physical road-
way conditions. There is little or no restriction in maneuver-
ability due to the presence of other vehicles, and drivers can
maintain their desired speeds with little or no delay.
Level of service B is in the zone of stable flow, with operating
speeds beginning to be restricted somewhat by traffic conditions.
Drivers still have reasonable freedom to select their speed and
lane of operation. Reductions in speed are not unreasonable, with
a low probability of traffic flow being restricted. The lower
limit (lowest speed, highest volume) of this level of service has
been associated with service volumes used in the design of rural
highways.
Level of service C is still in the zone of stable flow, but speeds
and maneuverability are more closely controlled by the higher
volumes. Most of the drivers are restricted in their freedom to
select their own speed, change lanes, or pass. A relatively
satisfactory operating speed is still obtained, with service
volumes perhaps suitable for urban design practice.
-------
Level of service D approaches unstable, flow, with tolerable operat-
ing speeds being maintained though considerably affected by changes
in operating conditions. Fluctuations in volume and temporary
restrictions to flow may cause substantial drops in operating
speeds. Drivers have little freedom to maneuver, and comfort
and convenience are low, but conditions can be tolerated for
short periods of time.
Level of service E cannot be described by speed alone, but repre-
sents operations at even lower operating speeds than in level D,
with volumes at or near the capacity of the highway. At capacity,
speeds are typically, but not always, in the neighborhood of 30 mph.
Flow is unstable, and there may be stoppages of momentary duration.
Level of service F describes forced flow operation at low speeds,
where volumes are below capacity. These conditions usually re-
sult from queues of vehicles backing up from a restriction down-
stream. The section under study will be serving as a storage area
during parts or all of the peak hour. Speeds are reduced sub-
stantially and stoppages may occur for short or long periods of
time because of the downstream congestion. In the extreme, both
speed and volume can drop to zero.
Capacity of a roadway section then, is specified as the capacity at a partic-
ular level of service. The term capacity by itself, however, is understood
to imply level of service E; this is the level of service at which the
maximum capacity occurs. When referring to capacity at a level of service
other than E, the term service volume is used (qualified by adding the
appropriate level of service).
Research as to the nature of highway operating characteristics has provided
the means for estimating the capacity (service volume at level of service E)
of both intersections and highway segments away from the influence of
intersections. An important result of this research has been to define a
relationship among various operating parameters including volume, capacity,
operating speed, and level of service. A general schematic representation
of this relationship is shown in Figure 2. This figure shows that the speed
and level of service deteriorate as the volume (expressed as a ratio with
the capacity of the facility) increases. Also, it is shown that once con-
ditions of forced flow and congestion (corresponding to level of service F)
occur, both speed and volume decrease dramatically. While Figure 2
is intended only to illustrate a concept, the actual numerical
19
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VOLUWE/CAP4CIT Y R4FIO
Figure 2. General concept of relationship of levels of
service to operating speed and volume capac-
ity ratio (not to scale)
relationship can be developed for any specific highway-type. In this
derived relationship, level of service and speed characteristics can be
developed as a function of volume and capacity. The actual relationships
will not be discussed here; rather, the reader if referred to the Highway
Capacity Manual9 or other traffic engineering texts.
The discussion above focuses primarily on segments of streets and highways
that are not influenced by intersections or other disruptions to normal
flow. It should be noted that the same types of relationships can be estab-
lished for intersections; however; in these relationships the primary con-
sideration is not with operating speed but with parameters that relate
to the amount of delay expected at the intersection. It should be obvious
that traffic operating characteristics are predictable to the extent that
information regarding the volume and capacity of the highway is available.
This concept is important because it provides the basis for an important
assumption used in developing the relatively simple technique presented
in this document for evaluating possible carbon monoxide problems. Since
the volume and capacity parameters are such key elements of the evaluation
procedure, further discussion of these are warranted.
20
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As stated, capacity (service volume at level of service E) refers to the
probable maximum number of vehicles that could pass a point on a roadway
during a given unit of time (usually vehicles per hour). The factors that
influence capacity vary with the type and location of the facility being
considered. Three general categories of capacity analysis can be discussed;
these include (1) analysis of freeways and expressways, (2) analysis of
urban streets and arterials, and (3) analysis of rural highways and arterials,
Freeways and expressways can generally be considered multilane facilities
(at least two lanes in each direction) characterized by the fact that direct
access to abutting land-use is eliminated in favor of exclusive service to
moving traffic. These facilities can also be considered to be comprised
of several components, each with separate capacity characteristics. The
separate components include: (1) the basic freeway section, (2) weaving
sections, and (3) ramp junctions. The capacity of a basic section is
about 2,000 passenger cars per hour per lane under "ideal" conditions.
In its standard usage ideal conditions imply:
• no commercial vehicles in,the traffic stream
• the design of the roadway is suitable for operating speeds
of 70 miles per hour*
• lanes are 12 feet wide
• no lateral obstructions within 6 feet of the pavement edge
When prevailing conditions are less than ideal, capacity is reduced. There-
fore, it is apparent that capacity is a function of elements such as:
• the percentage of trucks and buses in the traffic stream
• design characteristics such as the horizontal and vertical
alignment
• lane widths
• laterial clearance
*
This does not imply that the actual operating speed is 70 miles per hour.
21
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For weaving sections and ramp junctions, capacity is a function of the
same factors plus several additional elements that take into account the
friction developed in the free flowing traffic stream by the merging and
weaving activity. In order to account for the impact of these capacity
constraints, correction factors have been developed. These factors, as
well as the technique for applying them, are presented and discussed in
detail in the Highway Capacity Manual.^
The second general category pertains to capacity on urban streets and arte-
rials. Unlike freeways and expressways, urban streets and arterials are
intended to provide access to adjacent land development. The resulting
potential for interference from vehicles entering or leaving the traffic
stream significantly affects the capacity of a street. Of particular
importance in analyzing capacity on urban streets and arterials is the
consideration of intersections, especially signalized intersections.
Signalized intersections generally place the greatest constraint on the
capacity of urban arterials. This is so because it can be expected that
during a given time period, some fraction of the vehicles using the road-
way will be required to stop for a red signal. Obviously then, an impor-
tant determinant of the capacity of any intersection approach is the
amount of "green" signal time available for each approach. In traffic
engineering practice, the allocation of green time to an approach is
expressed in terms of the ratio of the green time (in seconds) allocated per
cycle, to the total cycle length (in seconds); this ratio is designated
G/Cy.*
The G/Cy value assigned to an intersection approach is a function of the
volume demand on that approach and the demand on the approach plus the
demand on other approaches. More specifically, the G/Cy for an approach
Normally the designation is G/C; G/Cy will be used in this report, how-
ever, for the sake of consistency since this designation has been used in
previous, related reports.
22
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is a function of the critical approach volumes during each separate signal
phase. Several definitions concerning traffic signals are required at
this point. First, oritioal approach volume is defined as the highest
hourly lane volume for all approaches that are allocated concurrent
green time. Obviously then, there are at least two critical approach
volumes associated with a signalized intersection.
Several definitions concerning the timing of traffic signals are important,
also. These definitions can best be developed by considering the inter-
section sketch and diagram shown in Figure 3.
The timing and phasing chart presented in Figure 3 shows various signal
messages that occur as a function of time. Each increment shown in the
timing chart is referred to as an interval. Interval then, can be defined
as the duration for any signal indication or message; note that intervals
usually are not uniform in duration.
Note the pattern of the green intervals; three separate time periods are
utilized in allocating green time to the approaches. Note that following
the yellow interval on approach D, the entire pattern repeats itself. The
time period beginning at "time 0," to the point where the pattern begins
to repeat (i.e., at the end of the yellow interval for approach D) is
referred to as a cycle. By definition, a oyole is the time required for
a complete set of interval sequences to occur. Optimum eycle length is
the theoretical cycle length that will minimize total delay time at the
intersection. Notice too, the pattern of green intervals occurring during
the cycle; three separate, nonoverlapping time periods are utilized in
allocating green time to the approaches. This indicates that the signal
represented in Figure 3 uses three phases. A phase is defined as a
portion of the cycle where a major movement is permitted.
23
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••-B
SIGNAL TIMING and PHASING CHART
SIGNAL FACING
• APPROACHES A, A1
• APPROACHES B, B'
• APPROACH C
• APPROACH D
SIGNAL INDICATION" /
G
G
Y
Y
R
R
G
R
1 1 • i • i '
R
Y
G
' 1 ' i
G
G
Y
Y
R
Y
R
G
R
1 1 • I • 1 ' 1
R
Y
G
i ' I
''
'(
R /
Y
' (
' ' ' '
ELAPSED TIME IN SECONDS
0 CODES'G=GREEN ,Y = YELLOW, R=RED
Figure 3. Signal timing and phasing at intersections
Traffic signals are operated by 3 controller unit, which can be one of
several general types. Fixed-time controllers are internally programmed
devices that provide for as many as three separate timing and phasing com-
binations for an installation. For certain applications these are being
replaced by more flexible and efficient actuated controllers that allocate
green time, phasing, and timing according to the traffic demand on each
approach.
The last consideration is whether or not a signal is part of a coordinated
system of signals. Interconnected signals are signal systems that provide
coordinated control over two or more separate intersections; this type of
24
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system is designed to coordinate the movement of platoons of vehicles so
that a platoon arrives at a signal at the beginning of the green interval.
This effectively reduces the total delay time at each intersection.
Isolated signals are those that operate independently of other nearby
signals. A summary of the most important considerations for signalized
intersections appears in Table 1.
Table 1. IMPORTANT FEATURES OF TRAFFIC SIGNAL INSTALLATIONS WITH
REGARD TO THE IMPACT ON TRAFFIC OPERATION
Parameter
• Cycle length
• Optimum cycle length
• Number of phases
(per cycle)
• Interval
• Critical volume
Units
Seconds
Seconds
None
Seconds
Vehicles
per hour
Remarks
Generally in the range of 40 to
120 seconds. Constant for
fixed-time installations, vari-
able (within certain limits) for
actuated systems. Longer
cycles minimize queue length but
increase total delay time for
stopped vehicles.
Primarily a theoretical value.
Generally 2 to 4 phases can be
used — more are possible.
Fewest phases possible are used.
Number of phases may vary for
actuated systems or fixed-time
systems with on-call pedestrian
signals.
Varies considerably for different
indications. Yellow interval
generally 4 to 6 seconds; green
usually a minimum of 10 seconds.
Directly related to green time
allocated. Critical volume is
defined for each phase.
Several texts contain detailed explanations of traffic signal operations
and theory; included are the Highway Capacity Manual,9 and the Institute
of Transportation Engineer's Transportation and Traffic Engineering
Handbook.10
25
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Capacity of intersection approaches controlled by STOP signs has not
received wide attention. Several studies have shown large variations in
capacity for different intersection configurations. A method for estimat-
ing the capacity of STOP-sign controlled approaches is presented 'in
Section IV.
Several additional, more subtle factors also affect capacity and operation;
these include (1) the size of the metropolitan area, (2) the distribution
of the volume demand during a given time-period (usually an hour), (3) the
number and width of approach lanes, and (4) the amount of interference to
flow caused by turning vehicles, pedestrians, buses (loading or unloading),
and the proportion of heavy trucks and buses in the traffic stream. These
factors and the manner in which they affect capacity are discussed in de-
tail in the Highway Capacity Manual.9
Again, the importance of capacity determination for highway sections not
influenced by intersections is that it provides a basis for estimating
travel speed, which is the primary determinant of emissions for these
types of facilities. At intersections, conditions of both interrupted and
uninterrupted flow occur. The free-flowing traffic is assumed to emit
carbon monoxide uniformly over a infinite line located at the centerline
of each traffic stream (as in the expressway location). Excess emissions
resulting from vehicle acceleration, deceleration, and idling are assumed
to be emitted over finite segments of each traffic stream. The length of
these finite line sources is determined by the average queue length that
develops on each intersection approach as a result of the imposed delay.
The quantity of emissions generated is a function of delay time, queue
length, and acceleration/deceleration rates, as well as cruise speed; each
of these factors is related to the capacity of the intersection.
An important expression of the utilization of a roadway is the volume-i-o-
sapaoity ratio (v/o). The volume to capacity ratios are most often uwe-.l
to express the relationship between (1) peak hour approach volume and
2.6
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approach capacity for a particular approach of an intersection, or (2) the
total peak hour volume (in one direction) and free flow capacity for a
highway or midblock arterial street section. As was shown in Figure 2,
v/c, is the primary determinant of operating speed for free flowing road-
ways. The v/c for signalized intersections is the key parameter for
estimating both queue lengths, the length of the line formed by vehicles
waiting at a red signal message, and delay time* the product of the
average duration of the stopped time at a signal, and the average number
of vehicles required to stop per cycle. This relation is significant
because, as was indicated previously, vehicles required to decelerate,
idle, and accelerate account for the excess emissions, which usually com-
prise the largest portion of total emissions generated at an intersection.
The volume element of v/c is obviously an important parameter. Several
different terms are used to describe various measures of traffic volume.
Perhaps the most widely used measure of traffic volume is the average
daily traffic volume or ADT, which is defined as the average 24-hour vol-
ume accommodated by a roadway in both directions for a specified time-period,
usually from 1 to 3 months. Average weekday traffic (AWDT) is conceptually
similar to ADT except that it (AWDT) is computed for weekday (Monday through
Friday) traffic volumes only. Average annual daily traffic (AADT) is the
total yearly volume accomodated divided by the number of days in the year.
Peak-hour volume is the highest number of vehicles determined to be pass-
ing through a roadway section during 60 consecutive minutes. Peak-hour
volume can also be described in terms of peak-hour lane volume. Peak-hour
lane volume refers to the individual lane volumes that occur during the
peak hour. It should be noted that the peak-hour lane volume may not re-
present the highest hourly volume for each lane since the peak hour is
determined by either the total roadway volume or the total volume entering
an intersection. For convenience, the peak-hour average lane volume can
often be used for many analytical procedures. This volume is simply the
total volume for one direction divided by the number of lanes (excluding
special purpose lanes such as turning or acceleration lanes) available to
accommodate traffic moving in that direction.
27
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An indication of the volume demand distribution during the peak hour is
provided by the peak-hour factor. The peak-hour factor describes the
ratio of the total peak-hour volume to the maximum flow rate during a
given time increment during the peak hour; this ratio must be qualified
by the specified time increment during which the maximum flow rate was
computed. The maximum flow rate (expressed in vehicles per hour) is
typically computed for time increments of 5 or 6 minutes for free-flowing
traffic, or for 15-minute increments for intersections. The peak-hour
factor has a maximum value of 1.0, which would indicate that the demand
during the hour does not vary to any significant extent.
Other types of volume data are routinely collected during typical traffic
studies. Vehicle classification counts are conducted to determine the
distribution of various types of vehicles using a facility. The propor-
tions are somewhat uniform between similar types of facilities, but
between facilities that perform dissimilar functions, wide variations
usually occur. Lane distribution is a parameter that defines the propor-
tion of the total roadway volume, usually for 1-hour increments, using
each lane. Similarly, directional distribution or directional split
(again, usually by hourly increments) for a highway is the proportion of
the ADT on a given traffic stream. The directional split for the peak
hour should be used for a worst case analysis.
Traffic volume patterns are typically uniform from day-to-day. This is
true to the extent that relative volumes for specific seasons, months,
days, or hours can be predicted from established trend data. This uni-
formity in volume patterns permits large scale analyses to be accomplished
with a relatively low level of effort directed at field counting programs.
This is a significant issue here since the procedures presented for
analyzing hot spots rely very heavily on areawide traffic volume data.
Substantial quantities of areawide volume data are often available from
state or local traffic engineering or planning agencies; therefore, the
techniques presented herein are considered to provide a realistic approach
to analyzing hot spot potential on an areawide basis.
28
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b. Other Environmental Considerations - Two parameters that are not
related to either traffic operation or roadway environment have a signif-
icant effect on vehicular emissions. The first of these is the ambient
temperature.
In order for ignition to occur in a gasoline engine, the fuel must be
vaporized just prior to the ignition phase, and also "there must be an
appropriate balance (ratio) between the quantities of vaporized fuel and
air that are present. Gasoline does not vaporize as readily when it is
cold as it does when temperatures are high. Therefore, when a "cold"
engine is being started, the quantity of gasoline that vaporizes is much
less than when the engine is operating at normal temperatures. To
compensate for this temporary imbalance in the ratio of vaporized fuel
to air, gasoline engines are equipped with a choke, which increases the
quantity of fuel taken into the combustion chamber and therefore reduces
the effective imbalance in the ratio and expediting fuel ignition.
Although the ratio of air to vaporized fuel becomes balanced when the
choke is functioning, the ratio of total air to fuel becomes imbalanced
because of the lack of the proper amount of combustion air. This imbalance
results in incomplete fuel combustion. A major product of incomplete
combustion of gasoline is carbon monoxide. Therefore, it is obvious that
temperature has some effect on emission rates.
The total implication of ambient temperature becomes apparent after con-
sidering the effects on an engine's operation. The amount of fuel
that is vaporized diminishes as temperature decreases. As a re-
sult, fuel entering the combustion chamber of an engine during the first
minutes of operation tends to quench the cylinder walls, thereby delaying
attainment of the stabilized temperature. The extent of this quenching
phenomenon is inversely proportional to temperature. Secondly, the choke
on most vehicles is actuated by a sensor incorporated into a temperature
sensitive engine component such as the exhaust manifold. The rise-time
from ambient to stabilized temperature for such components lags the rise-
29
-------
time in the combustion chamber by various amounts of time, thereby assur-
ing adequate choke-on time. The actual risertime is a function of ambient
temperature. Figure 4 provides an indication of choke-on time as a
function of temperature based on tests described in Reference 11.
Ambient temperature and time in operation parameters have an additional
impact on vehicles equipped with catalytic converters. During the first
several minutes of operation, the converter bed is not at the optimum
temperature for CO oxidation, therefore the CO emission rate during the
first few minutes of operation is greater than at the point when the op-
timum converter bed temperature is reached. Various analyses have shown
that time required for the converter bed to reach the designed operating
temperature is a function of ambient temperature.
Once the engine and converter bed temperature have stabilized and the choke
has opened, ambient temperature does not have a significant effect on the
emission rate. Obviously then, the effect of temperature variations is lim-
ited by time. The increment during which temperature effects occur (de-
fined as the first 505 seconds of operation after the engine has not been
run for at least 4 hours for noncatalyst vehicles, and 1 hour for catalyst
vehicles) is referred to as the cold-start operating mode. The amount of
time that a vehicle remains at ambient temperature with the engine not
operating is defined as the cold soak period.
10 -
9 -
- 7
UJ
2
P 6
5 I I 1 1 1 1 L
-"30 -20 -10 0 10 20 30
TEST TEMPERATURE, °F
Reproduced from) Reference II
Figure 4. Representation of choke-on time as a function of temperature
30
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The emission rate is also affected if the vehicle is restarted shortly
after being shut off. This is so because the temperature of both the air
under the hood and various engine components increases upon engine shutdown
since the engine cooling systems (fan and water circulation) cease func-
tioning as well. The higher temperature air is less dense than the nor-
mally cooler air, therefore the air to fuel ratio is reduced resulting in
higher emissions. Operation during the relatively short duration that
emissions are affected as a result of heat build-up is referred to as
hot start operation. The emission rate during hot-start operation is only
slightly greater than the rate during stabilized operation.
The second of the two environmental parameters is the altitude of the lo-
cation under consideration. Atmospheric pressure decreases with altitude,
therefore the mass of any given volume of air also decreases. The
result is that a stoichiometric imbalance occurs in the fuel combustion
phase of the engine operating cycle because of a deficiency in the mass of
available combustion air. Gasoline engines, then, tend to "burn rich"
(lower than desirable air-to-fuel ratio) at high altitudes, which has the
same net result as actuating the choke - carbon monoxide emissions increase
significantly.
D. RELATIONSHIP BETWEEN EMISSIONS AND RESULTING CONCENTRATIONS
The previous discussion served to define various concepts concerning car-
bon monoxide concentrations, and carbon monoxide emissions, including
emission sources, and factors affecting emission rates; the concepts of
concentrations and emissions were however, discussed as separate issues.
It is of interest to consider the relationship that obviously exists
between the carbon monoxide emissions generated along a street or high-
way, and the resulting concentrations measured at some point nearby.
Along expressways and arterial streets where conditions of uninterrupted
flow prevail, carbon monoxide emissions are assumed to be uniform over
the entire length of a traffic stream. A traffics stream is defined as
31
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all traffic lanes in one direction of travel. Furthermore, all emissions
are assumed to originate from the centerline of each traffic stream. Given
a uniform emission rate (based on traffic speed and volume), the CO con-
centration at a given location depends upon how much the emission is di-
luted with ambient air between the emission source (treated as an infi-
nite line) and the receptor site. Four factors influence this dilution,
(1) atmospheric turbulence, (2) wind speed, (3) distance between the
receptor and emission source, and (4) wind/road angle.
Atmospheric turbulence is induced by buoyancy forces related to the ver-
tical temperature structure and by mechanical disturbances caused by
surface roughness. Atmospheric stability is a measurement of turbulence
effected by the thermal gradient component. Stability categories are
qualitative classifications designated by letters of the alphabet. Class
A is the most unstable and class G the most stable. The atmosphere is
stable when the temperature increases with height and the vertical mixing
of air (hence, the upward spread of pollutants) is inhibited. An unstable
atmosphere implies a decrease in temperature with height, which enhances
vertical mixing.
Generally, the. worst-case stability that can occur during the day (when
peak-hour traffic flow generally occurs) is class D. Even at night,
class D is generally the most stable condition expected in urban areas.
This is usually the case when skies are overcast in urban or rural areas,
but it also occurs in urban and suburban areas on calm, clear nights when
rural areas experience very stable conditions. This decreased stability
in urban areas is due to heat island effects and increased surface rough-
ness. The atmosphere is slightly unstable (class C) or neutral (class D)
to a height several times that of the surrounding buildings. Thus, these
guidelines assume an atmospheric stability of class D as the worst case
condition in an urban area.
Mechanical turbulence is caused by rough terrain or by man-made obstruc-
tions to otherwise smooth wind flow. This mechanical turbulence increases
32
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dispersion of ground-level emissions. Manmade obstructions include build-
ings and vehicles. Moving vehicles can cause mechanical turbulence and
enhance the dispersion of their own emissions. To account for this, the
hot spot verification procedures employ an initial vertical dispersion
parameter, a , of 5 meters, a typical value for urban and suburban loca-
zo
tions where the source (roadway) is within 10 building heights of the
nearest building. The screening procedures, on the other hand, use a
more conservative value of 1.5 meters for a
zo
The ground-level pollutant concentrations resulting from emissions at a
given source are inversely proportional to the wind speed. As wind speed
increases, the emissions from a continuous source are introduced into a
greater air volume per unit time. The highest CO concentrations will
occur when the wind speed is low. A wind speed of 1 m/sec has been
assumed as the worst-case condition here.
Carbon monoxide concentrations diminish rapidly with distance from the
emission source. For the purposes of hot spot verification, the receptor
is assumed to be located at the centerline of adjacent sidewalks or at
the roadway right-of-way limit if no sidewalk exists.
The horizontal wind direction is usually the factor that most strongly
affects pollutant concentrations at a given receptor, since the bulk
transport is downwind. It is assumed in the hot spot procedure that the
wind is at the angle to the roadway that yields the highest CO concentra-
tion at the receptor site.
Once the roadway/receptor separation distance is specified and the worst-
case conditions are assumed, a normalized concentration term, xu/Q> can
be determined. The normalized concentration (xu/Q) is the product of
the concentration and wind speed, divided by the emission rate. Units
are m . The normalized concentration is a measure of the dilution of
the contaminant due to turbulent mixing. The worst expected CO concentra-
tion resulting from vehicle emissions on the roadway is obtained by
33
-------
multiplying the normalized concentration term by the emission rate and
dividing by wind speed (assumed to be 1 m/sec).
In the hot spot techniques, normalized concentration contributions from
both free-flow and excess emissions (due to queueing at intersections)
are obtained from graphs. These are corrected for roadway/receptor
separation distance, then multiplied by the corresponding emission rates
to obtain the concentration contributions from free-flow traffic and de-
layed traffic. The sum of these contributions is the total CO concentra-
tion resulting from vehicle emissions in the vicinity of an intersection,
while only the free-flow emissions are needed to estimate midblock or
uninterrupted flow conditions.
At certain locations in urban areas, the wind circulation patterns between
tall buildings may form a vortex. These conditions may exist in areas
called street canyons, which are characterized by specific building height
and separation relationship as discussed in Section IV.B.I. Diffusion char-
acteristics in street canyon situations are somewhat different from those
where a vortex does not form. As a result, special consideration must be
given to street canyons in the analysis of hot spots. These special
requirements are also discussed in Section IV.B.I.
E. DETERMINING THE CRITICAL SEASON
As was discussed previously, local carbon monoxide concentrations are a
function of emission rates (traffic conditions) and meteorological con-
ditions. To determine the "critical seasons," the time of the year with
the greatest potential for high carbon monoxide concentrations, one is
interested in periods when high emission rates and poor dispersive condi-
tions occur together. Choosing the critical season is important for hot
spot analysis for two reasons. First, the screening and verification
inputs appropriate for the critical season should be used in order to
obtain worst case estimates. Second, a number of parameters, especially
the correction factors, are sensitive to ambient temperature and vehicle
model-year distribution, both of which are directly related to the season
of the year.
34
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The simplest method of determining the critical season is to review monitor-
ing data to determine when the highest concentrations usually occur. In a
broad sense, only a quick review of the data is required. In practice,
some care must be exercised in choosing data for review to insure it will
be consistent with the purpose of choosing the critical season for hot
spot evaluations. In this regard, the data should be from sites that are
representative of general trends at hot spot locations and not from sites
that are designed to monitor background or regional levels. The EPA pub-
lication on monitor siting, OAQPS No. 1.2-012,l2 and especially Supple-
ment A,13 which is devoted to CO siting in particular, offer guidance as
to what general types of sites are suitable (also see Reference 14). These
site types are designated in Supplement A as "peak street canyon, peak
neighborhood, average street canyon, and corridor." The reader who is fami-
liar with these Hot Spot Guidelines should be able to judge the suitability
of sites falling in the above types for use in determining the critical season.
Problems that may arise include inappropriate monitor sites, inadequate
quantities of data, no data at all, or local anomalies causing inconsistent
identification of worst case season. A solution to the first three of
the problems is to apply verification procedures at a trial location using
seasonal traffic and meteorological data to identify the time of year that
produces the highest estimated concentrations. As an alternative, it would
be better to obtain data from a similar city or town within the same geographic
area and to use these data to identify the critical season. Such data
would, again, implicitly contain the joint effects of traffic and
meteorology. In addition, although the actual magnitudes of high CO
concentrations may be different (if data were available at the location
of interest to make the comparison), the important aspect is that the
highest values at both locations will tend to occur during the same time
of year.
The last problem area identified above, that of local anomalies, must be
dealt with on a case-by-case basis. In some instances an investigation
into the details of the actual monitor locations may be necessary to
35
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identify why differences occur in seasonal peaks at different sites.
For example, a monitor sited near a drive-in theater that operates during
the summer months only may identify (erroneously from an overall hot spot
evaluations viewpoint) summer to be the critical season. The local air
pollution control agency should be helpful in making these determinations.
F. EXAMPLE
This example is provided to illustrate some of the concepts discussed in
this section and in subsequent sections. In this section, one location is
introduced and described with regard to its operational and environmental
characteristics. The information presented here is input data to the
example that continues in the hot spot screening (Section III.D) and the
verification (Section IV.D).
The Lexington Street - School Street intersection in Waltham, Massachusetts
has been selected for the example. Figure 5 provides a sketch of the
location. This signalized intersection is located on the northern fringe
of the central business district. Lexington Street is the major arterial
connecting the northern portion of the city with the central core. School
Street, a minor arterial, parallels Main Street, the major arterial through
the CBD, and serves as a bypass to circumvent the CBD traffic congestion.
Because of its proximity to the CBD, vehicular traffic levels through
the intersection are uniform most of the day.
Both streets operate as 2-lane, 2-way facilities with parking permitted
only on the east side of Lexington Street's south approach and the north
side of School Street's west approach. The intersection is controlled
by an isolated fixed time signal controller. These general characteristics
are summarized in Table 2.
The signal phasing and timing is presented in Table 3. The total cycle
length is 60 seconds, with 32 seconds allocated to the green phase for
Lexington Street and 20 seconds for School Street. The remaining 8 seconds
36
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City/Town:
Location:
or.
By; 77W
Date:
Sketch of location and notes:
rfi
K
SCHOOL
10
"7
2 -i
fjtflut
Uj
1-5.
0
4.J.
/J.
Figure 5. Sketch of Lexington Street-School Street Intersection
37
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Table 2. TRAFFIC CHARACTERISTICS OF EXAMPLE INTERSECTION
Oo
Intersection: approach
School Street at Lexington Street
Lexington Street North
Lexington Street South
School Street East
School Street West
Description
2-lane
/ 2-way
)
Street
classification
Major
arterial
Minor
arterial
Curb
parking
None
east side
None
north side
Roadway
width,
m
9
9
8
10
G/Cy
0.53
0.53
0.33
0.33
ADT,
1977
14,000
10,000
8,000
9,000
Peak hour
traffic,
% ADT
6.5
6.5
6.5
6.5
Cruise
speed ,
nph
15
15
15
15
-------
Table 3. SIGNAL PHASING AND TIMING AT
EXAMPLE INTERSECTION
Signal facing
Lexington Street
School Street
Time, seconds
Signal indication
G
R
32
Y
R
4
R
G
20
R
Y
4
Table 4. EMISSION CORRECTION FACTOR CHARACTERISTICS
OF EXAMPLE INTERSECTION
Vehicle mix distribution
LDV
LDT
HDV-G
HDV-D
Vehicle operating mode distribution
Cold start
Hot start
Stabilized
Ambient temperature
78%
11%
6%.
5%
10%
10%
80%
30°F
39
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are split between the two streets for their respective yellow clearing
phases. The signal timing equates to a G/Cy of 32/60 or 0.53 for both
Lexington Street approaches and to a G/Cy of 20/60 or 0.33 for both School
Street approaches. Recall that the G/Cy assigned to an approach is a func-
tion of the critical volume demand on that approach and the demand on that
approach plus the demand on the cross street approach. Quantitatively it
can be expressed as:
(G/Cy)1 + (G/cy)2 ADT! + ADT2
Substituting the data provided in Table 2 for this intersection, the fol-
lowing results:
0.53 14,000 = ,
0.33 + 0.53 9000 + 14,000 U>OJ-
The allocation of the green time to the approaches is thus shown to be
distributed most efficiently.
The average daily traffic (ADT) ranges from a high of 14,000 veh/day to a
low of 8,000 veh/day as shown in Table 2. A vehicle classification count
at this intersection determined the distribution of the vehicle type using
the facility. These data are presented in Table 4. The peak-hour traffic
volume is approximately 6.5 percent of the total daily volume, and the
directional distribution for each approach is approximately 50 to 50. The
peak-hour directional traffic volume for any approach is the product of the
ADT, the fraction of the ADT occuring during the peak hour, and the direc-
tional distribution. The peak-hour traffic volume entering the intersection
from the north approach of Lexington Street is computed as:
(14,000)(6.5%)(50%) = 455
The peak-hour volume for the other approaches would be computed similarly.
Other factors discussed in this chapter will be added to the analysis of
Lexington Street at School Street in later sections of the guidelines.
40
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SECTION III
HOT SPOT SCREENING
A. INTRODUCTION
The screening procedures presented in this report are based on techniques
developed previously for estimating carbon monoxide concentrations in the
vicinity of indirect sources.i5»16 Before presenting these procedures, a
general discussion of their purpose and technical basis are in order.
1. Purpose of Screening
The screening process can be defined as a preliminary investigation of an
area to identify specific locations where carbon monoxide concentrations
may exceed the NAAQS. With respect to highway networks, the highest con-
centrations of carbon monoxide typically occur in the vicinity of inter-
sections where vehicle speeds are low and much vehicle acceleration, de-
celeration and idling takes place. Concentrations along limited access
highways or at midblock locations on arterial streets may also exceed the
NAAQS, therefore these locations must be considered in the screening pro-
cess as well. Owing to major differences in emission characteristics -
and hence in pollutant concentrations - separate screening techniques were
developed for highway intersections and midblock locations. Also, emission
characteristics of intersections will vary substantially depending on
whether or not traffic signals are utilized, therefore separate procedures
were also developed for both signalized and nonsignalized intersections.
41
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2. Screening Concept
Inasmuch as the effort here was directed toward development of a general
guideline for identifying carbon monoxide hot spots, consideration was
given to several issues that will have an influence on the methodology
utilized. First, in effect, the guidelines will be used to evaluate
literally hundreds of street sections and intersections within any munici-
pality; therefore, the parameters considered must be general enough to
require the absolute minimum of data input, yet the process must yield a
reliable assessment of hot spot potential. Second, the process should be
relatively simple and capable of being accomplished quickly., utilizing
data that is ordinarily available from state or city agencies. Third,
the process should be applicable (with perhaps minor modifications) to
any city or town where the existence of hot spot problems is suspected.
These factors, plus the fact that traffic operating characteristics are
often highly varied among similar locations (for example, among signalized
intersections), indicated that the screening process should involve a very
general approach, relying to a great extent on the validity of applying an
assumed set of conservative parameters in order to reduce to a minimum the
number of variables that must be considered in the process.
In general, then, the screening process involves establishing a relation-
ship between air quality and several general traffic operating character-
istics within the vicinity of an intersection or midblock section, based
on information provided in the Indirect Source Guidelines.16 The need for
further analysis of a particular location will then be based on whether a
potential air quality problem is indicated by the screening procedure.
Two standards exist for maximum carbon monoxide concentrations - the first,
40 mg/m3 (35 ppm) applies to a 1-hour average concentration, while the
second, 10 mg/m (9 ppm), applies to an 8-hour average concentration. For
most highway applications, the 8-hour standard is most often violated,
therefore, the screening process focuses on the 8-hour average concentration.
42
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3. Assumptions and Limitations
The implied relationship between air quality and traffic operating charac-
teristics actually is a relationship between air quality and emissions
intensity. In the vicinity of highways, emissions intensity depends on
parameters such as traffic volume, emission characteristics of the vehicle
fleet, quantitative and qualitative operating characteristics (capacity
and level of service) of the roadway or intersection, and the actual orien-
tation from the emissions source (e.g., the distance from and height above
the traffic lane). Also contributing to the emissions intensity at any
location is the background concentration that results from extra- and
intraurban diffusion of the pollutant (carbon monoxide), and the prevailing
meteorological conditions (macroscale and microscale).
Of the parameters outlined above, capacity and volume characteristic's will
vary most significantly among locations, while it can be assumed that the
other parameters are constant throughout an area. Therefore, the screening
f
process is based on an air quality-emissions intensity relationship where
emissions intensity is the independent variable and, also, where emissions
intensity is considered to be a function of two variables - volume demand
and traffic flow characteristics - and a constant set of factors to account
for the vehicle-fleet emissions characteristics, orientation and distance
from the source, background concentrations, and prevailing meteorology.
In developing the screening procedures, a distinction was made between
(1) the factors that influence CO levels and are site-specific and (2)
the factors that do not vary significantly from one site to another. Of
the factors mentioned in Section II, the highly site-specific elements are
traffic operational characteristics such as volume and vehicle speeds. Each
of these is thus determined separately for each location to be screened.
Several other factors are assumed to be common to an area for a worst case
analysis such as the composite emission factors, and meteorological factors.
In summary; the screening procedure uses (1) a standardized set of meteor-
ological conditions, (2) a standardized set of emission factors, and (3)
data on traffic operational conditions for each site to be analyzed.
43
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Because the purpose of the screening procedure is to efficiently identify
possible hot spot locations, it was necessary to include a number of sim-
plifying assumptions in the procedures. Where such assumptions were made
and where generalized conditions or relationships were included, they were
done so conservatively; that is the screening process is designed to over-
state possible CO levels rather than underestimate them in order to insure
that potential hot spots will not be missed. Each succeeding stage of
analysis has fewer assumptions, however. The screening requires the least
effort per site and thus has the greatest number of simplifying assumptions.
Verification allows a greater number of localized adjustments and thus is
more accurate; however, it requires greater effort per site, but need only
be performed for sites shown by screening to have hot spot potential.
Detailed computer modeling, not presented in this volume, requires the
greatest effort for each site and is the most flexible technique for
handling all variables.
a. Meteorological Assumptions - To simulate worst case conditions, the
screening procedure assumes a constant low windspeed (1 meter/sec or 2 mph)
for all locations. These conditions are reasonable for most areas as can
be seen in climatological records. As for wind direction, the procedure
assumes that the wind is at an angle to the roadway that tends to produce
the highest concentrations of CO. This assumption eliminates the need to
analyze seasonal wind direction frequencies separately for each inter-
section or midblock location to be analyzed. These assumptions are con-
servative because any given location will tend to experience every wind
angle during a year.
Another meteorological factor is ambient temperature. Inasmuch as the
peak CO concentrations tend to occur in the winter, and assumed ambient
temperature of 0°C (32°F) is reflected in the screening procedure. Colder
temperatures produce higher emission rates, and temperatures colder than
44
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0°G are certainly not uncommon.* The value 0°C was selected, however,
because it is perhaps representative of the range in winter afternoon
temperatures experienced throughout much of the U.S.
Additional assumptions are that stability category D prevails and that the
initial vertical dispersion parameter has a value of 1.5 meters. These
parameters were discussed in the previous section.
b. Traffic Assumptions - To minimize the need for collection of special
traffic data, the screening procedures were designed to use average daily
traffic (ADT) as the primary input. ADT statistics are generally available
for the primary streets in most regions from traffic engineering or planning
agencies. Implicitly, the screening procedure utilizes several assumptions
concerning hourly traffic distribution, lane distribution, and vehicle-type
distribution. Specifically, these assumptions are that:
• peak hour traffic represents 8.5 percent of the ADT;
• the directional split on midblock sections of arterials and
on expressways is 50 percent and 50 percent; at intersections,
the split is 50 percent and 50 percent;
• for multilane facilities, the volume of the outside
lanes (shoulder lanes) is equal to the inner lane
volume; and
• the traffic stream is comprised of 88 percent LDV, 8 percent
LDT, 3 percent HDV-G, and 1 percent HDV-D.
Again, each of these assumptions is judged to be reasonable for screening
purposes. As for verification, there is a provision for determining actual
hourly volumes. In both cases, there are additional assumptions regarding
signal operations and speed-volume-capacity relationships, which are dis-
cussed elsewhere in this report.
*
As an example, the mean daily average temperature in Boston is 30°F in
in January and February, which indicates there are many hours with tempera-
tures below the assumed 32°F; also there are 94 days per year in Boston
during which the minimum temperature is 32°F or below.
45
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c. General Assumptions - The screening procedures are based upon the
1982-1983 winter period; that is, the assumed vehicle population has the
emission characteristics of that time. This period was chosen because a
primary objective of the procedures outlined in these guidelines is to
identify locations where CO levels may exceed the NAAQS after the mandatory
compliance data, which is December 1982. Again, the highest ambient concen-
trations are usually expected to occur during the winter months, therefore
it is appropriate that conditions during the winter months subsequent to
the mandatory compliance data be reflected in the procedures presented
here.
A further assumption concerns receptor orientation with respect to the road-
way. Throughout the screening procedure, it is assumed that the receptor
is located along a line offset from the edge of the traveled way by 5 meters
at intersections and 10 meters at other locations.
d. General Comments - The procedures described here embody a number of
simplifying assumptions, the most important of which have been described.
Such simplifications are necessary to keep the screening process simple,
and these assumptions will apply more accurately to some locations than to
others. The user should recognize that the assumed conditions will not
be representative of conditions at all locations, but, overall, the pro-
cedures will produce a reasonable estimate of peak CO concentrations.
Again, the assumed general conditions were chosen to be conservative in
order to prevent overlooking hot spots. Later stages of the overall hot
spot analysis are more site-specific, less conservative, and thus more
accurate. The screening process is by design qualitative, and will only
identify those sites with the potential for violations of the NAAQS.
B. OVERVIEW OF THE SCREENING PROCEDURE
A description of the screening procedure must include discussion of three
critical elements, viz: (1) the data required, (2) the nomographs that
relate the roadway and traffic operating characteristics to air quality,
46
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and (3) a set of standard worksheets on which the input data and the results
of the analysis are recorded. Each of these elements is described below.
1. Data Requirements
The entire screening procedure may be possible to complete for many com-
munities with only a minimal field data collection effort. Data required
include areawide traffic volume data and a street inventory of sufficient
detail to indicate the lane composition (use and number of lanes), traffic
control utilized (mainly, the locations of signalized intersections are of
primary importance), and whether various streets operate one-way or two-way,
and whether or not congested conditions normally prevail. Also, additional
backup data are required to estimate the lane capacity of arterial streets
and expressways, as will be mentioned later. The data required for hot
spot screening for signalized intersections, nonsignalized intersections,
and arterials and expressways are summarized in Table 5.
a. Traffic Volume Data - Traffic volume data should be summarized in the
form of a traffic flow map indicating the highest monthly average daily
traffic (ADT) volumes for the winter season, reflecting the 1982-1983 period.
Volumes can be adjusted by the application of annual growth factors. Volume
data need not be developed for every street on the network; of primary
interest should be: (1) those streets and highways on the Federal Aid Sys-
tem, (2) those not on the Federal Aid System but that are controlled by
traffic signals; and (3) those not on the Federal Aid System but that are
considered by local officials to be "important" or high volume facilities.
Traffic volume is perhaps the most abundant data element available con-
cerning a highway network. The intent here is that existing data be used
wherever possible, implying that existing volume data should be available
in most instances to develop a suitable traffic flow map. In many com-
munities where traffic studies or transportation plans have been developed,
flow maps may already be available requiring only minimal updating.
47
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Table 5. SUMMARY OF DATA REQUIREMENTS FOR HOT SPOT
SCREENING
Signalized Intersections
• Location of signalized intersections.
• Street inventory to determine lane use and number and
directional operation of intersection approaches.
• Volume data (ADT) for all intersection approaches.
Nonsignalized Intersections
• Location of signed control intersections.
• Street inventory to determine lane use and number
and directional operation of intersection approaches.
9 Volume data (ADT) for all intersection approaches.
• Lane capacity on major through street
Uninterrupted Flow
• Location and number of lanes of expressway and ar-
terials of uninterrupted flow.
• Volume data (ADT) for the facility
• Roadway lane capacity
48
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Development of flow maps, however, should be carefully guided by cognizant
highway and transportation planning officials.
b. Highway Inventory Data - Highway inventories are normally available
from state transporation, planning or highway departments. These inven-
tories should be made available for each community where hot spots are
being investigated. The required data that can be obtained from these
inventories include descriptions of operational characteristics of the
roadways (e.g., one-way or two-way operation); information regarding the
number of lanes, use of medians, functional classification, etc., and
occasionally, volume data. Also, data must be obtained regarding inter-
sectional traffic control, particularly the locations where traffic
signals are utilized. It is helpful if the locations of all signalized
intersections are plotted on a base map.
c. General Backup Data - Other data elements are required that may not
be available from previous studies or from existing inventories. Included
is information required to estimate the lane capacity of streets' on the
network, mainly, estimates of truck factors, knowledge of conditions such
as restricted lateral clearances, severe terrain features, etc. This
information can be obtained through local planning or engineering per-
sonnel and by field reconnaissance. For a comprehensive discussion of
roadway lane capacity, the reader is referred to the Highway Research
Board's Special Report No. 87, the 1965 Highway Capacity Manual.9 A
methodology for calculating capacities based on this document is presented
in Section III.D of these guidelines.
2. Definitions
Several terms used in the screening procedure are defined below.
a. Comptex Intersection - This term refers to a signalized intersection
that, because of volume demand, turning movements, geoiretry, number of
approaches, etc., requires three or more signal phases. Also, an
49
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intersection characterized by very heavy pedestrian activity as well as
high volumes on all approaches may be considered a complex intersection.
Complex intersections cannot be appropriately analyzed using the screen-
ing procedure.
b. Speoial Case - A special case refers to either a signalized or non-
signalized intersection where conditions are such that, again, the screen-
ing procedure is not appropriate for evaluating hot spot potential.
Examples of special cases include (1) signals used only for certain events
such as during peak-hour only; or during work-shift changes if the loca-
tion is in the vicinity of a major industrial or office complex; (2) where
signals are manually operated or preempted in favor of traffic direction
by police personnel; (3) where signals are utilized for pedestrian cross-
ing protection only; and (4) where police control is utilized at non-
signalized intersections.
c. Conges ted/Nonconpested Areas - These terms are utilized in the screen-
ing procedure to indicate whether or not significant interference to traf-
fic departing from an intersection can be expected. For congested areas,
downstream cruise speeds will be fairly low (less than about 20 miles per
hour) with some interruptions occurring. In noncongested areas, however,
few if any interruptions to departing traffic will occur, and downstream
cruise speeds will be somewhat higher (at least 25 miles per hour).
3. Nomographs for Hot Spot Screening
The nomographs for screening provide the basic tool for relating various
traffic and roadway characteristics to hot spot potential. In particular,
these nomographs relate a roadway's average daily volume demand and capac-
ity characteristics to potential for exceeding the National Ambient Air
Quality Standard for 8-hour average concentrations of carbon monoxide
(10.0 mg/m3 (9.0 ppm)). Hot spot potential is indicated when the respec-
tive ADT's for any particular street under analysis and cross street are
50
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plotted on the nomograph and the point plotted falls on or above the
curve. The use of the nomographs is explained in detail in the following
paragraphs. Separate sets of nomographs are presented for three distinct
types of street locations including signalized intersections, nonsignalized
intersections, and for conditions where uninterrupted.flow prevails. Each
of these is discussed below.
a. Signalized Intersections - Ten separate nomographs are presented.
Each of the nomographs was developed for screening intersection approaches
of a particular configuration. Included are nomographs developed for
screening:
• 2-lane, 2-way (congested area)
• 2-lane, 2-way (noncongested area)
•• 3-lane, 2-way (congested area)
• 3-lane, 2-way (noncongested area)
• 4-lane, 2-way (congested area)
• 4-lane, 2-way (noncongested area)
• 3-lane, 1-way (congested area)
• 3-lane, 1-way (noncongested area)
• 2-lane, 1-way (congested area)
• 2-lane, 1-way (noncongested area)
A series of five curves appears on each nomograph. Each of these curves
represents a particular configuration of the cross street (with respect
to the approach being screened). Curves representing the following cross
street configurations are plotted on each nomograph:
• 2-lane, 1-way
• 2-lane, 2-way
• 3-lane, 1-way
• 3-lane, 2-way
• 4-lane, 2-way
Each of the curves is a plot of the ACT on the intersection approach under
analysis (abscissa) versus the ADT on the cross street (ordinate).
51
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Each point on any of the curves, then, represents that combination of
traffic volumes (on the street under analysis and the cross street) which,
under certain assumed conditions, would result in ambient carbon monoxide
concentrations at or very close to the 10.0 mg/m3 permitted by the National
Ambient Air Quality Standard for 8-hour average concentrations. These
assumed conditions include a maximum distribution of the available green
time between the street under analysis and the cross street,* which
accounts for the finite limits of the plotted curves on the nomographs.
Also assumed is that there is a background concentration present, which
comprises 2.9 mg/m3 of the implied 10.0 mg/m3 concentration. If the
respective ADT's for any particular configuration of street (under
analysis) and cross street are plotted on the nomograph and the point
plotted falls on or above the (cross street) curve, the implication is
that resulting carbon monoxide concentrations are potentially in the
vicinity of 10.0 mg/m^ or more, indicating that the approach has hot spot
potential. Plotting the ADT's (for winter 1982-1983) in this manner and
noting where the plot lies with respect to the cross street curve, is
essentially the entire procedure involved for using the nomographs. The
appropriate nomograph is selected based on the configuration of the
approach being analyzed while selection of the appropriate curve on the
nomograph is based on the cross street configuration.
b. Uninterrupted Flow - Two types of locations are considered where con-
ditions of uninterrupted flow prevail - these include expressways (con-
trolled access) and arterial streets. One nomograph is presented for
each of these two facility-types.
On the nomograph for expressways, three separate curves are plotted
representing 4-lane, 6-lane, and 8-lane expressways. These curves are
plotted as lane capacity (abscissa) versus ADT (ordinate). Each point
The G/Cy allocated to the street under analysis ranges from 0.20 to 0.80
representing the top left and bottom right extremities of the nomograph
curves, respectively. Recall that G/Cy is directly related to ADT and
that each approach must be allotted a minimum G/Cy.
52
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on the curve represents that combination of lane capacity and 24-hour
volume that, under certain assumed conditions, would result in nearby
ambient carbon monoxide concentrations of approximately 10.0 mg/m3. The
implication, again, is that for a particular roadway configuration with a
certain lane capacity, an ADT equal to or in excess of the "critical" ADT
(shown by the curve on the nomograph) indicates that the location may "be
a potential hot spot.
A similar nomography is presented for arterial streets showing the critical
ADT for various lane configurations. Again, if the actual ADT (estimated
for winter 1982-1983) exceeds the "critical" ADT, hot spot potential is
indicated.
The procedure, then, for using either of the nomographs is to plot the
estimated lane capacity versus its ADT and observe where this plot lies
with respect to the curve corresponding to the facility's configuration -
if the plot falls on or above the curve, hot spot potential is indicated.
c. Nonsignalized Intersections - Ten separate nomographs have been de-
veloped for the screening of nonsignalized intersections. These nomo-
graphs are utilized to screen intersection approaches controlled by STOP-
signs only; the through street approaches of a STOP-sign controlled inter-
section are screened utilizing the nomographs presented for uninterrupted
flow.
Each nomograph contains a curve representing the combination of ADT's on
the street under analysis and the through-street that would result in
ambient carbon monoxide concentrations of approximately 10.0 mg/m^ (assum-
ing certain other conditions prevail). Therefore, in order to use these
nomographs, two data elements other than the configuration of each street
approach must be determined, including (1) the ADT (winter 1982-1983) on
the street under analysis, and (2) the ADT (winter 1982-1983) on the major
53
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through street. Ifs then, the ADT's are plotted and the point lies on
or above the curve corresponding to the lane capacity of the major
approach, hot spot potential is indicated.
Selection of the nomograph is based on the configuration of both the STOP-
sign controlled street being analyzed and the major through street.
Nomographs were developed for the screening of the following STOP-sign
controlled street configurations:
• 2-lane, 2-way minor; 2-lane major (congested area)
• 2-lane, 2-way minor; 2-lane major (noncongested area)
• 2-lane, 2-way minor; 4-lane major (congested area)
• 2-lane, 2-way minor; 4-lane major (noncongested area)
• 4-lane, 2-way minor; 4-lane major (congested area)
• 4-lane, 2-way minor; 4-lane major (noncongested area)
• 2-lane, 1-way minor; 2-lane major (congested)
• 2-lane, 1-way minor; 2-lane major (noncongested)
• 2-lane, 1-way minor; 4-lane major (congested)
• 2-lane, 1-way minor; 4-lane major (noncongested)
4. Hot Spot Screening Worksheets
Presented in the following pages are standard worksheets to be used for
performing and reporting the screening of a street network. Included
are:
• Hot Spot Screening Summary Sheet - Worksheet 1
• Screening Worksheet-Signalized - Worksheet 2
Intersections
• Screening Worksheet-Nonsignalized - Worksheet 3
Intersections
e Screening Worksheet-Uninterrupted - Worksheet 4
Flow
54
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I
a. Screening Summary Sheet (Worksheet 1) - This form, as its name implies,
is intended to be used for summarizing the hot spot screening effort for a
community. The information to be entered on the sheet includes:
1. A description of each location analyzed - Broadway at
Park Street, or Vasser Street between Parson's Road
and Kennelworth Drive, for example.
2. The type of location analyzed - either signalized
intersection, nonsignalized intersection, freely
flowing arterial section, or expressway.
3. Whether or not hot spot potential is indicated by
the analysis.
The locations listed are then numbered sequentially.
b. Screening Worksheet - Signalized Intersections (worksheet 2) - This
worksheet provides space for the analysis of two separate intersections.
To complete this form enter the intersecting streets named in Part I, and
indicate whether or not the intersection is located in a congested area
in Part II. (A congested area implies cruise speeds of less than 20 mph).
In Part III, it is indicated whether or not the location should be con-
sidered a complex intersection (unusual geometery) or a special case.
For locations that are not considered complex intersections or special
cases, the actual screening is performed in Part IV.
In Part IV each approach to the intersection is analyzed separately.
Under the main column heading "Approach Under Analysis," the approach
designation (name and orientation such as Amity Road, south approach),
the adjusted (i.e., projected 1982) average daily traffic volumes, and the
roadway configuration (for example, 4-lane, 2-way) are entered.
Under the other main column heading of "Cross-Street Data," the appro-
priate data elements for the cross street approach having the highest
traffic volume are recorded. Then, utilizing the appropriate nomograph
and curve, a determination of hot spot potential is made and recorded.
If the configuration of the other approach of the cross street is different
55
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from the approach previously used in the analysis, the procedure is re-
peated using the data for the second cross-street approach and the appro-
priate nomograph and curve. Note that columns f and j provide space to
record the figure number and curve designation for the nomograph used to
perform the screening.
c. Screening Worksheet - Nonsignalized Intersections (Worksheet 3) - This
worksheet allows for the analysis of four nonsignalized intersections.
In the first major column, the through street is analyzed in the same
fashion as for uninterrupted flow conditions. Each approach of the con-
trolled cross street is then analyzed in the two columns under the heading
of "Cross-Street Data."
d. Screening Worksheet - Uninterrupted Flow (Worksheet 4) - Up to 30
locations where conditions of uninterrupted flow prevail can be analyzed
on each of these worksheets. The data required include the facility
name; a description of its location; its volume, configuration, and capac-
ity, and finally, whether or not hot spot potential is indicated.
5. Performing Hot Spot Screening
Detailed instructions on performing hot spot screening are provided in
Section III.C which follows. Prior to this detailed discussion it may
be helpful to look at the process in general terms; this can be best
illustrated by a flow diagram as shown in Figure 6.
As can be seen from the flow diagram, the first steps involve compiling
the required data. Once this has been completed, screening begins.
First, all signalized intersections are screened, followed by locations
where uninterrupted flow prevails, and finally, nonsignalized intersec-
tions. The importance of the order of analysis becomes apparent in the
*
following detailed discussion.
56
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COMPILE TRAFFIC, ROADWAY
AND PLANNING DATA
1 _ •
f
DEVELOP/OBTAIN TRAFFIC OBTAIN LIST OF TRAFFIC SIGNAL
FLOW MAP FOR 1977-78 LOCATIONS, TOWNWIDE
1
1
i
t
PERFORM SCREENING OF
EACH SIGNALIZED INTERSECTS
<
©
\
f
OF UNI
<
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<
""HOT SPOT
pINOI GATED 7---"*
CREgUIREDT VERIFICATI°
' 1 '
A
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t
ERFORM SCREENING OF
VTIONS WHERE CONDITIONS
NTERRUPTED FLOW PREVAIL
-"HOT SPOT --»^^
INDICATED? _^>
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EOUIREO1 VERIFICflTI°
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*
RECORD
t PERFORM
Rf ,. .
r
SCREENING
OF NONSISNALIZEO INTERSECTIONS
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( HOT SPOT VERIFICATIOI
V. REQUIRED
. - .- .
RECORD R
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e»ii|,T(( L . j,
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DEVELOP/OBTAIN OTHER
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1
—/'use NOMC-
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*^
«Y
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9RAPHS PROViOED>
S 7 THRU 16 y
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ruSE NOMOGRAPHS PROVIDED^
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/'USE wtx
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FOLLOW UP WITH HOT
SPOT VERIFICATION
Figure 6. Process flow diagram for the screening of
carbon monoxide hot spots
57
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C. DETAILED INSTRUCTIONS FOR HOT SPOT SCREENING
The following presents detailed instructions for performing hot spot
screening based on utilizing the data, nomographs, worksheets, and general
procedure discussed in the previous portion of this section. Included
are step-by-step instructions for the three subtasks (analysis of sig-
nalized intersections, uninterrupted flow, and nonsignalized intersec-
tions) involved in the screening process.
1. Screening Signalized Intersections
a. Step 1 - Prepare a townwide traffic flow map depicting the highest
monthly projected ADT's on the street network for the winter months
(November through March) of 1982-1983. This should be presented on a
suitable base map (or maps) at a scale of between 1 inch = 1,000 feet
and 1 inch = 3,000 feet; insets at a larger scale should be used, as
appropriate, for congested areas. Volumes should be included for all
principal streets including, as a minimum, all streets and highways on
the Federal Aid System and on all street sections controlled by traffic
signals.
b. Step 2 - Determine the locations where traffic signals are utilized
to control traffic.
c. Step 3 - Determine the configuration (i.e., the number of approach
and departure lanes) of each approach for all signalized intersections.
Also, a determination should be made as to whether each intersection is
located in a congested or noncongested area, and whether any of the loca-
tions should be classified as complex intersections or special cases
(unusual geometry or unusual signal control such as by a police officer).
58
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d. Step 4 - Enter appropriate data for each signalized intersection on
the Screening Worksheet - Signalized Intersections (see Worksheet No. 2)
as follows:
1. Part I:
a. Enter the location (e.g., Main Street at Naussam Road).
2. Part II:
a. Record whether or not the location is generally within a
congested area.
3. Part III:
a. Record whether or not the location should be considered
a complex intersection or special case (see definitions on
pages 49 and 50). If it is either a complex intersection or
a special case, enter the location on the Hot Spot Screening
Summary Sheet (Worksheet No. 1) and proceed to the next
intersection.
b. If the location is neither complex nor a special case,
proceed to Part IV.
4. Part IV: Each approach of the intersection is analyzed as follows:
a. Enter the approach designation (e.g., Main Street, south
approach) in column a. It is important to identify the
particular approach being considered (e.g., Main Street,
south approach).
b. Enter the adjusted ADT (winter 1982-1983) in column b.
c. Enter the configuration (e.g., 2-lane, 1-way) of the
approach in column c.
d. Enter the name and orientation (e.g., Main Street, east
approach) of each cross street approach on the line
above columns d through k.
e. For the first approach of the cross street:
1. Enter the adjusted ADT (winter 1982-1983) in column d.
59
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2. Enter Its configuration (e.g., 2-lane, 1-way) in
column e.
3. Enter the figure number and curve to be used for
screening in column f (see Section III.B.3 beginning
on page 50 for instructions on the selection of
figures and curves).
4. Using the figure and curve noted in column f, deter-
mine whether or not hot spot potential exists; record
this determination in column g.
f. For the other approach of the cross street:
1. Enter the adjusted ADT (winter 1982-1983) in column b.
2. Enter its configuration (e.g., 2-lane, 2-way) in
column i.
3. Enter the figure number and curve to be used for
screening in column j (see Section III.B.3 beginning
on page 50 for instructions on the selection of figures
and curves).
4. Using the figure and curve noted in column j, deter-
mine whether or not hot spot potential exists; record
this determination in column k.
g. Repeat the previous steps in Part TV for each approach.
After all approaches have been analyzed, enter the location on
the Hot Spot Screening Summary Sheet (Worksheet No. 1); include
the following data:
a. Location (street names).
b. Type (in this case, signalized intersection)
c. Whether or not a hot spot is indicated - a hot spot is indi-
cated if any entry in columns g or k is affirmative.
e. Step 5 - Repeat Step 4 for all signalized intersections on the street
network.
2. Screening Locations Where Conditions of Uninterrupted Flow Prevail
a. Step 1 - Identify sections of expressway (controlled access) where the
following conditions prevail:
60
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Highway configuration ADT
4-lane highway >_ 40,000
6-lane highway > 50,000
8-lane highway > 65,000
These ADT's are slightly below those that would generally have hot spot
potential.
b. Step 2 - For each section identified in Step 1 as meeting the above
criteria, enter the highway name or route number in column (a) of the
Screening Worksheet - Uninterrupted Flow (Worksheet No.4). Also
on this worksheet, enter the following data for each location:
1. Description of the location (e.g., north of the Brook's High-
way Interchange) in column b.
2. The adjusted ADT (winter 1982-1983) in column c.
3. Highway configuration (e.g., 4-lane expressway) in column d.
4. Estimated lane capacity in column e (see Section III.D beginning
on page 70).
5. Using the appropriate curve in Figure 17, determine whether
or not the facility is a potential hot spot (for instructions
on selecting the appropriate curve and use of the figure, see
page 52); record this determination in column f.
c. Step 3 - Upon completion of Step 2, record the locations on the Hot
Spot Screening Summary Sheet; include:
1. Facility name and location (from columns a and b of the
worksheet.
2. Type of facility (in this case, expressway-uninterrupted
flow).
3. Whether or not hot spot potential is indicated (from
column f of the work sheet.
d. Step 4 - Identify arterial street sections on the highway network that
meet the following criteria:
61
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1. Volumes:
Highway configuration ADT
2-lane arterial >_ 15,000
4-lane arterial >_ 25,000
6-lane arterial > 35,000
2. Proximity to Signalized Intersections: The section should
at least 1 mile from a signalized intersection.
e. Step 5 - For each arterial section identified in Step 4 as meeting
the above criteria, enter the street name (or other identifier) in
column a of the Screening Worksheet - Uninterrupted Flow (see Sec-
tion III.B.4). Also on this worksheet, enter the following data for
each location:
1. Description of the location (e.g., between Marginal Way
and Ober Road) in column b.
2. The adjusted ADT (winter 1982-1983) in column c.
3. Street configuration (e.g., 4-lane arterial) in column d.
4. Estimated lane capacity in column e (see Section III.D. beginning
on page 70).
5. Using the appropriate curve, in Figure 18, determine whether or
not the facility is a potential hot spot (for instructions on
selecting the appropriate curve and use of the figure, see page 52
page 52); record this determination in column f.
f. Step 6 - Upon completion of Step 5, record the locations on the Hot
Spot Screening Summary Sheet; include:
1. Facility name and location (from columns a and b of the
worksheet).
2. Type of facility (in this case, arterial-uninterrupted flow).
3. Whether or not hot spot potential is indicated (from
column f of the worksheet.
62
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3. Screening Nonsignalized Intersections
a. Step 1 - Identify all nonsignalized intersections where either the
major street or controlled street volumes exceed the critical ADT's shown
below (for various street configurations):
Street configurations
Critical ADT's
Major street
2~lanes
4-lanes
4-lanes
Controlled street
2-lanes
2-lanes
4-lanes
Major street
10,000
20,000
20,000
a
Controlled street
2,500
2,500
8,000
SUnder control of STOP sign.
b. Step 2 - For each intersection identified in Step 1 as meeting the
above volume criteria, enter the location in Part I of the Screening
Worksheet - Nonsignalized Intersections (Worksheet No.3).
c. Step 3 - For Part II of the worksheet enter the following:
1. For the major through street enter:
a. Adjusted ADT (winter 1982-1983) in column a.
b. Configuration (e.g., 2-lane arterial) in column b.
c. Using Figure 18, determine whether or not hot spot
potential exists on the through street (see Section
III.B.3.b on page 52 for instructions on selecting
the appropriate curve); record this determination in
column c.
2. For the first controlled street approach enter:
a. Street name and its orientation (e.g., Trask Lane,
• east approach).
b. Adjusted ADT (winter 1982-1983) in column d.
63
-------
c. Configuration (e.g., 2-lane, 2-way) in column e.
d. The figure number to be used for screening in
column f (see Section II.B.S.c on page 53 for
instructions on the selection of figures and curves).
e. Using the figure designated in column f, deter-
mine whether or not hot spot potential exists;
record this determination in column g.
3. For the second controlled street approach enter:
a. Street name and its orientation (e.g., Trask Lane,
west approach).
b. Adjusted ADT (winter 1982-1983) in column h.
c. Configuration (e.g., 2-lane, 1-way) in column i.
d. The figure number and curve to be used for screening
in column j (see Section III.B.3.C on page 53 for
instructions on the selection of figures and curves).
e. Using the figure and curve designated in column j,
determine whether or not hot spot potential exists;
record this determination in column k.
d. Step 4•__— Upon completion of Step 3, record the locations on the Hot
Spot Screening Summary Sheet; include:
1. Location (street names).
2. Type (in this case, nonsignalized intersection).
3. Whether or not a hot spot is indicated - a hot spot is -indicated
if any entry in columns c, g, or k is affirmative.
4. Other Locations
Other locations may be identified during the initial screening that should
be analyzed for possible hot spot potential. These locations may not be
obvious solely from analyses of traffic data; however, interviews with
local planning or engineering personnel may result in the identification
of such locations. These special cases may include access roads to major
64
-------
industrial facilities or office complexes, shopping centers, or public
parking areas. Should locations such as this be identified, they should
be entered on the Hot Spot Screening Summary Sheet.
5. Screening Locations Map
The final step in the hot spot screening process is to assign an identifi-
cation number to each location listed on the Hot Spot Screening Summary
Sheet, and then to plot the locations, with their respective identification
numbers, on a base map. In preparing this map, separate symbols should be
utilized to distinguish signalized intersections, nonsignalized inter-
sections, and locations where uninterrupted flow prevails.
6. Nomographs and Worksheets
The following pages bring together most of the information that is needed
to perform hot spot screening, assuming the user has become thoroughly
familiar with both the general discussion of the concepts of hot spot
analysis and the specific screening instructions presented above. These
pages may be separated from this document and reproduced in order to
provide a hot spot screening workbook. It is noted, again, that Vol-
ume III3 of the Guidelines series provides a summary of the screening
procedure and is designed specifically for easy use by an analyst who
is familiar with the details of the screening procedure described here.
Presented first in Figures 7 through 28 are nomographs for screening sig-
nalized intersections, arterial streets, expressways, and STOP-sign con-
trolled intersections. Following these are Worksheets No. 1 through 5
to be used in performing the screening of a community and recording the
i
results.
65
-------
WORKSHEET NO. 1
Hot Spot Screening Summary Sheet page of
City/Town: . State:
Analysis By: __________________________ __________________ Date:
(MM) (tltU)
Approved By: ___________________________ ____________________ Date:
(title)
Hot Spot Indicated
or
Location Type Detailed Analysis Requirec
Yes F No ~
66
-------
City/Town:
Analysis By:
Approved By:
WORKSHEET NO. 2
Screening Worksheet - Signalized Intersections
page of
State:
(tui.)
Date:
Date:
<«*•)
(title)
Part I Location:.
Pitt II Congested Area? Yes;.
-No
Part III Complex Intersection or Special Case7 v««; No: If yes, enter location on Initial Screening
Summary Sheet and proceed to next Intersection; if no, proceed with Part IV.
Part IV Analyze each approach separately on the form below.
A|i|iro.ic(i unrliT flimtvulM
•
De«t Knat Ion
^"~^r===--==criir
b^
Adjusted
ABC
X
c
Conf Ifcur-
ac.on
X
ttM-ni! , A|>prn:ifli i
i_
Adli'iied
Afr
e_
CtmLlijur-
(_
flr.ure/
s.
Hoc s|ioi
Street: Approach:
Street: Aiipnuirhi • , , ,
h_
Ar<>m'li imdiT JHIH
a
Df ilgnJtlon
^^==:~~===^2
X* III
b
Adjusted
ADT
X
£
Conf lyur-
flt ton
^x^
Crens-itrcet data
St rort : Appronchi
d
Ail liTvU'd
APf
u
Ctmf lyur-
iHlnn
(_
Figure/
curve nsrd
a.
Hut spot
Ini'.lcilcd?
Street: Approach:
Street : Approach:
1^
Ad just od
APT
i
Conf 1 «;tir-
at Ion
1
FUure/
curve used
k_
Hot spot
IndUitriT
Street: Approach:
67
-------
City/Town:
WORKSHEET NO. 3
Screening Worksheet - Nonsignalized Intersections pase
State:
.01
Analysis By:
Approved By:
(title))
firt I lacetlom.
I'art 11 Analyze each cross street approach on the form below:
Date:
Date:
Through etreet date
_£
Adjuitcil
ADI
J»
Conf Igur-
itton
C_
Hot Spot
indicated?
Street i Approach:
a
Adjulted
ADT
e
ConHgur-
• tlon
f
figure/
curve ueed
&
Hot Spot
Indicated!
Street: Approach:
h
Adjusted
ADT
i
Conf Igur-
etlon
i
Figure/
curve uied
k
Hot Spot
Indlceted?
Pert I Ucetlont.
Part II Analyze each cross street approach on the form below:
Through etreet dete
_e_
Adju.ttd
ACT
£
Conf Igur-
• tlon
c
Hot Spot
indicated?
H
Street! Approach:
d
Adjulted
ADT
£
Conftgur-
f
Figure/
&
Hot Spot
Street: Approach:
h
Adjulted
ADT
l
Conf Igur -
etlon
1
Figure/
curve ueed
k
Hot Spot
Indlceted?
Ftrt I locetlon:.
Part II Analyze each cross street approach on the form below:
ft
Adjusted
ADT
_b
Conf Igur-
etlon
c
Hot Spot
indicated?
Minor croee etreet date
Str«U Approach:
d
Adjulted
ADT
e
Conf ! dur-
ation
f
Figure/
curve uicd
t
Hot Spot
Indicated?
Street: Approach:
h
Adjuited
ADT
i
Configur-
ation
i
Figure/
curve ueed
k
Hot Spot
Indlceted?
rart I Location:.
Part TI Analyze each cross street approach on the form below:
Adlutted
ADT
Through et
Configur-
ation
reet data
Hot Spot
indicated?
1
Street!
d
Adjulted
ADT
' '
Approach :
Configur-
ation
{_
riguri/
curve uifd
a
Hot Spot
Indicated?
t
h
Adjuited
ADT
1
Conf igur-
J.
risurfl/
k
Hot Spot
68
-------
City/Town:
Analysis By:
Approved By:
WORKSHEET NO. 4
Screening Worksheet - Uninterrupted Flow
State:
page of
Date;
(tttU)
Date!
(till.)
facility
Location
Adjutctd
AOT
Configur-
ation
ElC.
Unt
capacity
Hat Spat
Indicated!
69
-------
D. METHODS OF ESTIMATING ROADWAY CAPACITY
This section provides a methodology for calculating roadway or lane capac-
ities, based on the Highway Capacity Manual,9 for use in the hot spot
screening procedures.
The methodology developed here is conservative in that it tends to under-
estimate capacity.
The Highway Capacity Manual (1965)9 gives the following maximum uninterrupted
flow capacities under ideal conditions for various types of roadways:
Highway type Capacity (vph)
Multilane 2,000 per lane
Two-lane, two-way* 2,000 total (both directions)
Three-lane, two-way 4,000 total (both directions)
The capacity, C, of a multilane roadway is computed using the following
equation:
C = 2000 M Wf T; (4)
the capacity for one direction of a two-lane roadway is computed using the
equation:
C = 1000 Wf T (5)
where M = number of lanes moving in one direction
Wf = adjustment factor for lane width from Table 6
T = truck factor from Table 7.
This applies primarily to rural locations where speed ranges are quite
high; for most urban applications, capacity can be assumed to be about
2000 vehicles per hour for each direction.
70
-------
Table 6. COMBINED EFFECT OF LANE WIDTH AND RESTRICTED LATERAL CLEARANCE
ON CAPACITY AND SERVICE VOLUMES OF DIVIDED FREEWAYS AND EX-
PRESSWAYS AND TWO-LANE HIGHWAYS WITH UNINTERRUPTED FLOW
Distance from
traffic lane
edge to
obstruction
Adjustment factor, Wf , for lane width and lateral clearance
Obstruction of one side of
one-direction roadway
12-ft
lanes
11-ft
lanes
10-ft
lanes
9-ft
lanes
Obstructions on both sides
of one-direction .roadway
12-ft
lanes
11-ft
lanes
10-ft
lanes
9-ft
lanes
Four-lane divided freeway, one direction of travel
6
4
2
0
1.00
0.99
0.97
0.90
0.97
0.96
0.94
0.87
0.91
0.90
0.88
0.82
0.81
0.80
0.79
0.73
1.00
0.98
0.94
0.81
0.97
0.95
0.91
0.79
0.91
0.89
0.86
0.74
0.81
0.79
0.76
0.66
Six- and eight-lane divided freeways, one direction of travel
6
4
2
0
1.00
0.99
0.97
0.94
0.96
0.95
0.93
0.91
0.89
0.88
0.87
0.85
0.78
0.77
0.76
0.74
1.00
0.98
0.96
0.91
0.96
0.94
0.92
0.87
0.89
0.87
0.85
0.81
0.78
0.77
0.75
0.70
Two-lane highway, one direction of travel
6
4
2
0
1.00
0.97
0.93
0.88
0.88
0.85
0.81
0.77
0.81
0.79
0.75
0.71
0.76
0.74
0.70
0.66
1.00
0.94
0.85
0.76
0.88
0.83
0.75
0.67
0.81
0.76
0.69
0.62
0.76
0.71
0.65
0.58
71
-------
Table 7. AVERAGE GENERALIZED ADJUSTMENT FACTORS FOR TRUCKS ON
FREEWAYS AND EXPRESSWAYS, AND 2-LANE HIGHWAYS OVER
EXTENDED SECTION LENGTHS
Pt, percentage
of trucks, %
1
2
3
4
5
6
7
8
9
10
11
14
16
18
20
1
2
3
4
5
6
7
8
9
10
12
14
16
18
20
Factor, T, for all levels of service
Level terrain
Rolling terrain
Mountainous terrain
Freeways and expressways
0.99
0.98
0.97
0.96
0.95
0.94
0.93
0.93
0.92
0.91
0.89
0.88
0.86
0.85
0.83
0.97
0.94
0.92
0.89
0.87
0.85
0.83
0.81
0.79
0.77
0.74
0.70
0.68
0.65
0.63
0.93
0.88
0.83
0.78
0.74
0.70
0.67
0.64
0.61
0.59
0.54
0.51
0.47
0.44
0.42
Two-lane highways
0.99
0.98
0,97
0.96
0.95
0.94
0.93
0.93
0.92
0.91
0.89
0.88
0.86
0.85
0.83
0.96
0.93
0.89
0.86
0.83
0.81
0.78
0.76
0.74
0.71
0.68
0.64
0.61
0.58
0.56
0.90
0.82
0.75
0.69
0.65
0.60
0.57
0.53
0.50
0.48
0.43
0.39
0.36
0.34
0.31
72
-------
s of vehicles
f 1
EET,thousond
r
^
£ "J
in
(O
o
(E
IO
O
h-
o
<
5
C
)
2
IK
1^
s.
Ik
*>
\
N
<
\
\
\
\
\
\
\
\
A
%
^^
\
^
V
s
k^
s
6
HOT SPOT POTENTIAL IS INDICATED.
IP THE POINT PALLS ON OR AMVE
THE APPROPRIATE CURVE.
\
^Q
c,
*.p"
^
\
S,
s
S
x
^
k,
^s
K
V
\
S
V
t
e
A 4 Ion
B 3 lam
C 3 Ian
0 2 Ian
E 2 Ian
h^
v
s
,_
^^
X
V
s,
V
s^
"N,
s«^
•s^
^
•v
*v
"X.
'X
II -•
t —
» —
B —
9 —
'V
S»
X,,
•^,
•X,
1
2 way
2 way
Iway
2 way
1 way
*«v
V
^i
"*N
«*»
•»
V
s
X,
•V,
"*•
1
t
ADT ON STREET UNDER ANALYSIS ' 2 lone -2 way, CONGESTED AREA
thousands of vehicles
Figure 7.
Analysis at signalized intersections of a 2-lane, 2-way
street and various cross street configurations in a
congested area
73
-------
30-
w
9
W
ic
•
^
c
o
Ul
o
tr
o
20-
15-
10-
^
\N
HOT SPOT POTENTIAL IS INDICATED
IF THE POINT FALLS ON OR ABOVE
THE APPROPRIATE CURVE.
A 4 lana -2 way
B 3 lane —2 way
C 3 lane —I way
0 2 lane —2way
E 2 lane — I way
10
12
AOT ON STREET UNDER ANALYSIS' 2 loot -2way, NONCONGESTED AREA
thousands of vehicles
Figure 8. Analysis at signalized intersections of a 2-lane, 2-way
street and various cross street configurations in a
noncongested area
74
-------
HOT SPOT POTENTIAL IS INDICATED
IP THE POINT PALLS ON OR ABOVE
THE APPROPRIATE CURVE.
A 4 lane —2way
B 3 lane —2 way
C 3 lane —I way
D 2 lane —2way
E 2 lane — I way
10
12
ADT ON STREET UNDER ANALYSIS: 3 lane-2way, CONGESTED AREA
thousand* of v«hlcl«»
Figure 9. Analysis at signalized intersections of a 3-lane, 2-way
street and various cross street configurations in a
congested area
75
-------
w
o
o
•
o
id
I-
(O
(O
(O
o
cr
Q
<
HOT SPOT POTENTIAL IS INDICATED
If THE POINT PALLS ON OR ABOVE
THE APPROPRIATE CURVE.
A 4 Ian* -2 way
B 3 lone —2 way
C 3 lane — I way
D 2 lane —2way
E 2 lane — I way
0
024 6 8 10 12
ADT ON STREET UNDER ANALYSIS' 3 lane -2 way,NONCONGESTED AREA
thousands of v«hic!ts
Figure 10. Analysis at signalized intersections of a 3-lane, 2-way
street and various cross street configurations in a
noncongested area
76
-------
s of vehicles
' 1
:ET, thousand
i\
1
ee
K
V)
O
a:
u 10
IU
§
*-
a
<
0
ADT
2 <
ON STREET ^
\
\
(\
^
ij
IDER
HOT SPOT P
1
{(
\\
\\
F 1
me
\\
\\(
\J\U
vi\\\
Mu
\\\\
\v\
w
v\
\
rHE
: i
v
\
\
\
V
0
\
6
ANALYSIS^
K
kPP
\
W
A
S
L
\
\
DIN
ROI
\
.
s
s
\
s
€
4 Ian
•OT
T 9
>RI
EN
*AL
AT
TIA
LS
E <
L IS INDICATED.
ON OR ABOVE
SORVE.
A 4 lane —2 way
B 3 lane —2 way
C 3 lane -1 way
D 2 lane — 2 way
E 2 lane — 1 way
V,
^
\
^^
^S
V
Si
'A
*D
D^
'C,
lt*
1
9-2\
^s.
"^*«
••fc
"*«,
^N
••**
^•S
•**.
1
vay, C
^.^
••»,
•*«
*^.
"v,
~^
•^i
^
3
ON6E
— ,
i
STED
2
AREA
thousands of vehicles
Figure 11. Analysis at signalized intersections of a 4-lane, 2-way
street and various cross street configurations in a
congested area
77
-------
w
"o
C
O
Ul
UJ
Or
cn
(O
v>
o
-------
30
. i i i i i I I—till
HOT SPOT POTENTIAL IS INDICATED
IP THE POINT FALLS ON OR ABOVE
THE APPROPRIATE CURVE.
A 4 Ion* —2way
B 3 Ian* —2 way
C 3 lan« — I way
D 2 lant —2woy
E 2 lane — I way
AOT ON STREET UNDER ANALYSIS =3 !on« -1 way, CONGESTED AREA
thousands of vthiclis
Figure 13. Analysis at signalized intersections of a 3-lane, 1-way
street and various cross street configurations
79
-------
UJ
UJ
(T
I-
V)
CO
CO
o
QC
O
O
o
<
HOT SPOT POTENTIAL IS INDICATED
IF THE POINT FALLS ON OR ABOVE
THE APPROPRIATE CURVE.
A 4 Ion* —2way
B 3 lane — 2 way
C 3 lane — I way
D 2 lane —2way
E 2 lane — I way
ADT ON STREET UNDER ANALYSIS =3 lone - I way, NONCONGESTED AREA
thousands of v«hlclts
Figure 14. Analysis at signalized intersections of a 3-lane, 1-way
street and various cross street configurations for
noncongested areas
80
-------
30-
u
JS
•
C
o
20-
UJ
£ 15-
CO
V)
o
tr
° .0-
HOT" SPOT ilorUuL Is
'|P THE POINT PALLS ON OK AtOVE
-THE APPROPRIATE CURVE.
A 4 Ion* —2way
B 3 lane —2 way
C 3 lane —I.way
D 2 lane —2way
E 2 lane — I way
10
12
ACT ON STREET UNDER ANALYSIS« 2 lone -1 way, CONGESTED AREA
thousands of vehiclts
Figure 15. Analysis of signalized intersections of a 2-lane, 1-way
street and various cross street configurations
81
-------
u
ie
•
o
UJ
UJ
V)
V)
O
a
<
HOT SPOT POTENTIAL IS INDICATED
IF THE POINT FALLS ON OR AIOVI
THE APPROPRIATE CURVE.
A 4 lone -2 way
B 3 lane —2 way
C 3lon« — I way
D 2 loot —2way
E 2 lane — I way
ADT ON STREET UNDER ANALYSIS'2 lana -Iway, NONCON6ESTED AREA
thousands of vthlclts
Figure 16. Analysis at signalized intersections for a 2-lane, 1-way
street and various cross street configurations in
noncongested areas
82
-------
80-
70-
60-
i
I
40-
O
30-
20-
10
12
J8-LANE EXPRESSWAY
8-LANE EXPRESSWAY
4-LANE EXPRESSWAY.
.HOT SPOT POTENTIAL IS INDICATED
IP THE POINT PALLS ON OR A»OVC
THE APPROPRIATE CURVE.
I I I I I
14
16
18
20
LANE CAPACITY, vph
Figure 17. Analysis for uninterrupted flow conditions of controlled
access facilities (expressways) for various lane
configurations
83
-------
I
CM
5
•fl
» .S
t- s
S i
to
o
<
50
40
30
£ 20
10
HOT SPOT POTENTIAL 18 INDICATED.
IP THE POINT PALLS ON OR ABOVE
THE APPROPRIATE CURVE.
7.5
10
12.5
0 2.5 5
ADT ON CONTROLLED STREET ' 2 lane - 2 way , CONGESTED AREA
in thousands of vehicles
Figure 19. Analysis at nonsignalized intersections of a 2-lane, 2-way
controlled street intersecting a 2-lane, 2-way or 2-lane,
1-way major street in a congested area
85
-------
40-
30-
«
*" 25-
I
€ 20-
O
o
15-
10-
s
^
e-LANE' ARTERIAL
4-LANE ARTERIAL'
2-LANE ARTERIAL
HOT SPOT POTENTIAL IS INDICATED
IP THE POINT FALLS ON OR AIOVE
THE APPROPRIATE CURVE.
14
16
18
20
LANE CAPACITY, vph
Figure 18. Analysis for uninterrupted flow conditions of uncontrolled
access facilities (arterials) for various lane configurations
84
-------
50
r
o
CM
*-_*
g O
~ 1
i o
40
30
H O
Ul «
u 2
a: P
w
ac
o
|
o
<
f 20
10
V
>
t
\
\
V
\
k
S
L
S
HOT SPOT POTENTIAL 13 INDICATED
IP THE POINT PALLS ON OR ABOVE
THE APPROPRIATE CURVE.
\
V
\
N
I
—
2.5
7.5
10
12.5
ADT ON CONTROLLED STREET: 2 lone -2way , NONCONGE8TED AREA
in thousand* of vehicles
Figure 20. Analysis at nonsignalized intersections of a 2-lane, 2-way
controlled street intersecting a 2-lane, 2-way or 2-lane,
1-way major street in a noncongested area
86
-------
ADT ON MAJOR STREET * 4 lone -2 way
in thousands of vehicle*
— ro w * c
3 O O O O C
H 1
VI
\
\
\
\
\
L
V
\
N
1
s
MOT SPOT POTENTIAL IS INDICATED..
r THE POINT PALLS ON OR AIOVE
THE APPROPRIATE CURVE. ~
V
\
k
s
V
>
^
>
k
\
k
\
\
2.5
7.5
10
12.5
ADT ON CONTROLLED STREET'2 lone-2 woy, CONGESTED AREA
in thousands of vehicles
Figure 21. Analysis at nonsignalized intersections of a 2-lane, 2-way
controlled street intersecting a 4-lane, 2-way major
street in a congested area
87
-------
50
o
CM
g U
UJ tt
* '
2
o
<
40
30
I 20
10
J L
J_
J L
HOT SPOT POTENTIAL 13 INDICATED.
IP THE POINT FALLS ON OR ABOVE
THE APPROPRIATE CURVE.
_L
J I
0 2.5 5 7.5 10 12.5,
AOT ON CONTROLLED STREET = 2 loot - 2 woy , NONCONGESTED
in thoutondt of vehicle*
Figure 22. Analysis at nonsignalized intersections of a 2-lane, 2-way
controlled street intersecting a 4-lane, 2-way major
street in a noncongested area
88
-------
CM
II
I*
w "S
UJ °
or M
fe I
i I
l -
§
50
40
30
10
Ill
HOT SPOT POTENTIAL 18 INDICATED.
IP THE POINT PALLS ON OR ABOVE
THE APPROPRIATE CURVE.
N
2.5
7.5
10
12.5
ADT ON CONTROLLED STREET'4 lanes - 2 way, CONGESTED AREA
in thousands of vehicles
Figure 23. Analysis at nonsignalized intersections of a 4-lane, 2-way
controlled street intersecting a 4-lane, 2-way major
street in a congested area
89
-------
CM
I
il
K- *
I I
* 1
O X
i;
HOT SPOT POTENTIAL 18 INDICATED
THE POINT PALLS ON OK AiOVE
THE APPROPRIATE CURVE.
12.5,
ADT ON CONTROLLED STREET '4 lane-2 way , NONCONGESTED AREA
in thou»om!« of vehicle*
Figure 24. Analysis at. nonsignalized intersections of a 4-lane, 2-way
controlled street intersecting a 4-lane, 2-way major
street in a noncongested area
90
-------
DU
>»
I 40
I
CM
5 5
e '£
el * 30
i •»
• 0
-i
£• I
iii 5
w * 20
H e
o:
s
10
O
0
<
ft
m
•••
^
s:
>v
[S
V
v
>
k
s
^
\
)
v
N
i
k
>
HOT SPOT POTENTIAL IS INDICATE!
P THE POINT PALLS ON OR AtOVE
THE APPROPRIATE CURVE.
w
s
^
\
A
s
N
1
>__
0 2.5 5 7.5 10 12.5
ADT ON CONTROLLED STREET ' 2 lane -1 way , CONGESTED AREA
in thousand* of vehicles
Figure 25. Analysis at nonsignalized intersections of a 2-lane, 1-way
controlled street intersecting a 2-lane, 2-way or 2-lane,
1-way major street
91
-------
ou
AOT ON MAJOR STREET = 4 lone - 2 woy
in thousonds of vehicles
— IS> (X *
o o o o o
k
\\
\
\
>
\
\ I
i
\
\
\
>
L
\
^
\
MOT SPOT POTENTIAL IS INOICATCI
F THE POINT PALLS ON OR AiOVf
THE APPROPRIATE CURVE.
^
\
^
\
\
\
V|
\
Ni
i
)
0 2.5 5 7.5 10 12.5
ADT ON CONTROLLED STREET '2 lone -I way, CONGESTED AREA
in thoutondt of vehicle*
Figure 27. Analysis at nonsignalized intersections of a 2-lane, 1-way
controlled street intersecting a 4-lane, 2-way major
street
93
-------
I
T
i
(M
O
CVJ
I
K
3
<
»-
o
<
HOT SPOT POTENTIAL IS INDICATED
IP THE POINT PALLS ON OR ABOVE
THE APPROPRIATE CURVE.
0 2.5 5 7.5 10 12.5
ADT ON CONTROLLED STREET -2 lone -Iwoy, NONCONGESTED AREA
in thoutondt of vehicles
Figure 26. Analysis at nonsignalized intersections of a 2-lane, 1-way
controlled street intersecting a 2-lane, 2-way or 2-lane
1-way major street in a noncongested area
92
-------
CM
'.9
§3
» S
fi!
or -5
si
li
o
HOT SPOT POTENTIAL IS INDICATED.
IP THE POINT PALLS ON OR ABOVE
THE APPROPRIATE CURVE.
0 2.5 5 7.5 10 12.5
ADT ON CONTROLLED STREET '2 lone -I way, NONCONGESTED AREA
in thousand* of vehicle*
Figure 28. Analysis at nonsignalized intersections of a 2-lane, 1-way
controlled street intersecting a 4-lane, 2-way major
street in a noncongested area
94
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E. EXAMPLE
An example is provided in Figure 29 of the screening of a signalized inter-
section, School Street at Lexington Street. The traffic data required to
perform the screening were presented previously in Section II.F. (See
Figure 5 in Section II.F for details of the intersection layout.)
The detailed instructions for screening signalized intersections were pre-
sented in Section III.C.I. The first three steps in the screening process
concern the collection of data. The information required include ADT and
configuration for each approach to the intersection. All four approaches
at the School Street - Lexington Street intersection consist of two lanes
and serve traffic in two directions. The ADT's for the approaches are:
Lexington Street, north approach 14,000
Lexington Street, south approach 10,000
School Street, east approach 8,000
School Street, west approach 9,000
Step 4 provides the instructions for the actual screening, as represented
by Figure 29. The intersecting street names are entered in Part I.
Because this location is influenced by activities associated with pedes-
trian and vehicle parking movement, and because of the narrow roadway
width and influence from nearby intersections, it has been determined
that the intersection should be classified as a congested area. This fact
is recorded in Part II. The intersection is neither complex nor a special
case; this is recorded in Part III.
The procedure set down in Part IV analyzes the hot spot potential of the
intersection. All intersection approaches are analyzed. Only one approach,
Lexington Street north, is described here, however. The information is
recorded as shown in Figure 29. The approach under analysis, its ADT, and
its configuration are entered in Columns a, b, and c, respectively. The
ADTs and the configuration of the cross street (School Street) approaches
95
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rart I Location:.
SCHOOL
Pact II Congested Area? X. Yea; No
Part III Complex Intersection or Special Gate? V««; X No: II yea, enter location oc Initial Screening
Summary Sheet and proceed to nut intersection; if no, proceed wlKti Part 3V,
P*tt IV Analyze each approach separately on the form below.
Leg under en*ly9la
•
Dct 1 gnat ton
LEXlM-j'lOMj MORTH
LCXIMGIOW, Sfvj-rc
JII^^'^^^IIIL
^'- ~OOL j E*OT
SCHOOL Vitrr
b
A'J lusted
14000
10 000
^X^J
scco
^ooo
c_
• «T. lor>
2L/?W
2i-./?W
^x^
2L/7W
2L/2W
Street: SCHOOL L.-1L: C
Ail H'.t cO
a rooo
8000
a
^^.^w
!'../?»>'
1
7-D
7-D
S.
YE5
YES
Street: L. E XI NK-'T o SJ Approach: N
HOOO
woe;
i L .'l v/
^L/?w
7-0
7-D
V£S
Yes
Scrcet : -^ C. *"\ C1' '
h
"300O
^OOO
If,: W
i
:L/?^
*L/:W
Street: LtX\Ni>Tt
10000
IOOCG
7-£»
7-D
Yes
Yfb
M Approach: ^j
2 L 'I-*.' i 7'/5
e;./zw
7'0
Y6S
Yes
Figure 29. Example screening
96
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are entered in the appropriate columns - ADTs in columns d and h, the
configurations in columns e and i. In this case, both Lexington and School
Streets have 2-lane 2-way (2L/2W) configurations.
The next step is to determine which screening curve is appropriate for the
specified conditions. Figure 7 provides curves for the analysis of a
2-lane 2-way street (in this case, Lexington Street) in a congested area
for signalized intersections. Because School Street is a 2-lane 2-way
street, curve 0 in Figure 7 is selected and this is recorded in colums f
and j.
To determine the hot spot potential for the Lexington Street north approach,
the point corresponding to 14,000 on the abscissa and 8,000 on the ordinate
is plotted in Figure 7. Since this point is above and to the right of
curve D, hot spot potential is indicated for the Lexington Street north
approach.
97
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SECTION IV
HOT SPOT VERIFICATION
A. INTRODUCTION
Section III presented a screening technique for identifying locations on a
highway network where the potential exists for traffic-generated carbon
monoxide emissions to exceed the NAAQS for 8-hour average concentrations for
the winter of 1982-1983. The screening technique.was designed specifically
for performing an areawide assessment of an entire city or town using only the
most basic data elements and a number of simplifying assumptions. It was
stressed that various assumptions used in developing the screening technique
were intentionally conservative. As a result, many of the locations identified
as potential hot spots by the screening process may, in fact, not be hot spots
after all. In order to verify the hot spot potential of a location further anal-
ysis is required utilizing a technique that accounts for physical and opera-
tional characteristics particular to that location. The purpose of this sec-
tion, then, is to present a technique for quantifying the hot spot potential
at locations where the screening process indicated such potential exists.
B. OVERVIEW OF HOT SPOT VERIFICATION
The verification process is a followup to the screening of an area. Con-
ceptually, the technique involved is identical to that used for the screen-
ing. It assumes an explicit relationship between air quality, traffic
operating characteristics, and physical characteristics of an intersection,
for particular meteorological conditions. Therefore, if both traffic and
physical characteristics are determined, and a particular set of meteoro-
logical conditions assumed, estimates of the resulting air quality can be
98
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made. Again, these estimates are made using a series of curves that
relate various traffic and roadway characteristics to resulting air quality.
The purpose of the verification process is to provide a quantitative estimate
of the highest potential 1-hour and 8-hour average carbon monoxide in the
vicinity of the roadway under analysis. Since a worst-case analysis is being
performed, it is desirable to maximize the effects of traffic, meteorology,
and receptor siting. Thus, the CO concentration estimate should be made
using peak hour traffic data, temperatures typical of cold winter days,
and low windspeeds (1 m/sec). The concentration curves presented in this
section were derived from data presented in References 15 and 16. Concen-
tration estimates are maximized by locking receptor location and wind direc-
tion into a worst case configuration for freeways and intersection (see
Volume II for rationale).
In discussing the verification process it is necessary to consider the
three basic elements of the procedure - these include the data required,
the curves to be used, and a set of standard worksheets to be used for
performing and recording the verification of potential hot spots.
1. Data Requirements
While in the screening process it was emphasized that maximum use should
be made of existing general traffic data, the verification process requires
current data specific to each site analyzed. However, existing data may
be used if they are determined to be representative of current traffic
conditions and of sufficient detail. The required data are outlined below,
and summarized in Table 8. In all oases observed data should supersede
suggested estimates herein when these data apply to the locations being
modeled. Specific guidance for estimates is given in the worksheet instruc-
tions.
a. Location Sketch - A sketch should be prepared of each location requiring
verification. This sketch should show:
99
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Table 8. SUMMARY OF DATA REQUIREMENTS FOR HOT SPOT VERIFICATION
Data element
Remark
Location sketch
Traffic volume
Vehicle speed
Receptor separation
Vehicle classification
Traffic signal operation
Vehicle mode operation
Temperature
The sketch should dimension the traffic engin-
eering features, identify the geometry of the
location and identify traffic operational
constraints.
Peak hour volume projected to the analysis year
for the busiest winter season month.*
Estimate of operating cruise speed.
The distance between the receptor site and the
centerline of the traffic stream.
Distribution of traffic by vehicle type: LDV,
LOT, HDV-G, HDV-D.
Signal timing and phasing at signalized
intersections.
Distribution of vehicles by operating mode:
cold-start, hot-start, stabilized.
Ambient temperature representative of winter
days.
the approximate geometry of the location
the number of approach and departure lanes on each
roadway if the site is an intersection, or just the
number of lanes if the site is an expressway or mid-
block location
the width of each lane, shoulder, median, and channelizing
island
the locations within each site where curb parking is per-
mitted, where bus stops and taxistands are located, and
the width of such parking lanes
the location of the worst-case receptor site (see part d
below)
See discussion concerning critical season beginning on page 34.
100
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• pertinent notes regarding observations as to the operation
of. the facility.
b. Traffic Volume - Peak hour volume data (or projected data) averaged
per lane are required for all streets and highways analyzed. These volumes
should be representative of the busiest month from November through March.
This implies that a statistical data base must also be available from which
projections are made. The directional split of peak hour traffic is also
required since computations of carbon monoxide concentrations are performed
on a traffic stream basis.
While traffic volume data are often the most abundant data generally
available, in many instances sufficient data may not exist to perform hot
spot verification, and new data will be required. Again, the validity of
existing data must be judged. Ideally, the development of all traffic
volume data used in the verification process should be accomplished by a
competent engineering or planning professional, and may require direction
at the state level.
c. Vehicle Cruise Speed - Estimates of the cruise speed of freely flowing
vehicles and vehicles departing from signalized intersections must be made.
These can be based on actual field studies or through estimates based on
observed operating characteristics and surrounding land use. Several
figures and tables, which appear later in this section, have been pro-
vided to aid in making these estimates.
d. Roadway/Receptor Separation Distance - The separation distance, x,
between the receptor site and traffic streams in both directions (for both
uninterrupted flow locations and intersections) is required. This is the
minimum perpendicular distance in meters from the centerline of the traf-
fic stream to a line parallel to the roadway drawn through the receptor
site; that is, the offset distance from the centerline of the traffic
stream (all lanes in one direction of travel) to the centerline of an
adjacent sidewalk or edge of right-of-way.
101
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For intersections, the receptor is a point defined by the offset distance
from the centerline of the traffic stream, and a specified back distance
from the intersection. The distance back from the intersection is a func-
tion of the queue length that develops. The user is not required to compute
the distance nor is he required to compute queue length; rather, empirical
relationships between volume demand and queue length are used implicitly
so that volume and traffic signal parameters (as will be explained later)
are the only inputs required.
e. Vehicle Classification Data - Another data requirement is the distribu-
tion of traffic by vehicle type. This is usually developed for specific
highway classifications such as expressways, major arterials, minor arte-
rials, etc. The vehicle classifications that should be identified include:
• light-duty vehicles (passenger cars) - LDV
• light-duty trucks (panel and pickup trucks, light
delivery trucks - usually all 2-axle, 4-wheel
trucks) - LDT
• heavy duty, gasoline-powered trucks - HDV-G
• diesel-powered trucks - HDV-D.
• motorcycles - MC
These data may be available for a community where recent comprehensive
transportation planning programs have been accomplished.
f. Traffic Signal Data - A necessary element in the verification of hot
spot potential at signalized intersections is the ratio of the green time
allocated to each approach, to the total cycle length (G/Cy). This ratio
can be determined from records or design plans if the installation is of
the fixed-time type but if actuated control is utilized, the ratio must
be computed based on the actual peak hour volumes.
Where actuated pedestrian signals are used, estimates should be made of
the number of times during the peak hour that the actuated pedestrian
phase is called. Also, where turning lanes are provided and these lanes
are subject to interference from stopped through traffic, estimates of
102
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this interference should be made. The green time allocated to the approaches
affected by these occurrences then must be adjusted. (Refer to worksheet
for worksheets for guidance in estimating G/Cy.)
g. Percentage of Cold-Start Vehicles - Estimates of the proportion of
cold-operating vehicles in the traffic stream during the peak hour are
required. This is a difficult statistic to determine for specific loca-
tions; therefore it is recommended that a very general approach be taken
involving the use of the results of a recently completed study13 that
focused on determining the proportion of cold-operating vehicles in numerous
traffic streams in two U.S. cities. This study concluded that the distribu-
tion of cold-operating vehicles is a function of the time of day and the
type of location. For instance, it was determined that the fraction of
vehicles operating in the cold mode during the morning in the CBD was sub-
stantially different from the fraction operating at the CBD during the
evening; also, the fraction of cold-operating vehicles at locations in the
CBD differed significantly from the fraction in say, residential areas for
the same time-period. In the absence of data specific to a location under-
going hot spot analysis, it is recommended that the fraction of vehicles
operating in the cold mode be estimated using the information in the
worksheet instructions.
h. Percentage of Hot-Start Vehicles - The proportion of vehicles operating
in the hot-start mode must also be estimated. This parameter, like the cold-
mode fraction, is not easily determined. The actual impact of hot-start
vehicles is not nearly as significant as the cold-start fraction, however.
Again, guidance is provided in estimating this parameter in the worksheets.
i. Temperature - Ambient temperature has a significant effect on the emis-
sions from cold-operating vehicles and the time necessary to achieve normal
operating temperature. Colder temperatures produce higher emission rates.
Since a worst-case analysis is being performed, a temperature typical of
that during the peak traffic hour on cold winter days (or critical season)
should be used.
103
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j. Street Canyons - At some midblock locations' and intersections in urban
areas, a vortex motion may develop in the wind circulation between tall
buildings. This occurs in areas referred to as "street canyons." A sche-
matic of this windflow pattern is depicted in Figure 30. A vortex will
form when two conditions exist; first, the roadway/wind angle, 9, must be
at least 30°, and second, the penetration depth, 6, of the rooftop wind
into the street canyon, must be less than the average height, H, of the
upwind buildings. In the analysis of hot spots, an assumption can be made
outright that the roadway/wind angle is 30 , but the rooftop wind penetra-
tion depth must be calculated using the equation:
6 = 7 (kW/u)2
where k = turbulent diffusivity of momentum - 1 m2/sec
W = street canyon width (building-to-building), m
u = rooftop windspeed, m/sec
7 = an empirical nondimensional constant.
(6)
BACKGROUND
CO CONCENTRATION
•i, j > &,
Figure 30. Schematic of cross-street circulation between buildings
104
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Again, in these Guidelines, the criterion for roadway/wind angle can be
assumed to be met so that the user must only check the building height and
penetration depths.
When the vortex forms, dispersion of CO along roadways is different com-
pared with dispersion along open areas. To reflect these different, dis-
persion characteristics, a separate technique is introduced into this anal-
ysis that better describes street canyon dispersion. This is accomplished
by introducing the street canyon criterion for penetration depth in the
worksheets (again, the roadway/wind angle criterion is assumed to be met),
and special procedures are defined throughout if a street canyon situation
is indicated.
When applying the street canyon calculations to an intersection, only the
main link (determined beforehand) is considered. Since the CO concen-
tration computed using the street canyon procedure may be lower than if the
nonstreet canyon procedure is used, it may be useful in many instances to
use both techniques so that hot spot potential can be assessed more
completely.
k. Miscellaneous Data - This category includes information relative to
planned projects that will directly impact traffic or travel within the
study area in the near future. These could involve alteration to the
street network, (e.g., adding or deleting major arterials or expressways,
revising circulation patterns, changing signal systems, etc.), or the
development of programs to create mode shifts, (e.g., improving bus ser-
vice for commuters). The expected effect on traffic volumes must be
considered where these possibilities exist.
*
It is noted that the affects of other nearby links in terms of concentra-
tions at receptors located in a street canyon have not been investigated
thoroughly, and thus are assumed at this time to have minimal impact at
the receptor.
105
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Another area of consideration is the effect of programs that will have an
impact on automotive emissions, such as mandatory inspection and mainten-
ance programs. Where such programs are in effect or are anticipated,
their impacts should be estimated.
2. Hot Spot Verification: Process, Assumptions, and Limitations
The hot spot verification process will yield the expected worst-case carbon
monoxide concentration in the vicinity of the roadway. The procedure can
be summarized as follows for each location:
1. Specify the site-specific traffic and roadway parameters.
2. Determine the optimum receptor placement (instructions follow
the worksheets).
3. Determine the emission rates.
4. Apply emission correction factors to account for variability
in calendar year, vehicle mix, temperature, altitude, and
percent of cold operating vehicles.
5. Determine the normalized concentration contribution of the
roadway(s) at the receptor site.
6. Apply the distance correction factors.
7- Apply the 8-hour averaging factor, if appropriate.
8. Add the background carbon monoxide concentration.
Basically, the verification procedure summarized above consists of solving
the following equation for the expected peak carbon monoxide concentration
for an 8-hour averaging period:
X
8
= C,
/u + X
B
106
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where xg = the estimated 8-hour average CO concentration at the
receptor;
Cg = empirical conversion factor to change from a 1-hour
averaging time to an 8-hour averaging time;
i
CEJ = free flow emissions correction factor combining the
effects of calendar year, vehicle-mix, altitude, tempera-
ture, proportion of cold-operating vehicles, and
state (California or non-California);
C = excess emissions correction factor combining the effects
of calendar year, vehicle-mix, altitude, temperature,
proportion of cold-operating vehicles, and state
(California or non-California);
Qf = the emission rate (g/m-sec) of carbon monoxide
from freely flowing traffic;
(xu/Q)f = the normalized concentration (m"1) at the receptor
resulting from free-flow emissions;
Cd = distance correction factor for the concentration
contribution from free flow emissions;
Q = the excess emission rate from interrupted flow due
to idling, acceleration, and deceleration (g/m-sec),;
(xu/Q) = normalized concentration due to excess emissions from
interrupted flow (nf1);
Cd = distance correction factor for the concentration con-
f\
tribution from excess emissions from interrupted flow;
u = windspeed (m/sec); and
Xr, = background concentration, 8-hour averaging time.
B
and where
i = approach index
n = number of lanes
m = number of approaches.
The verification procedure utilizes the following assumptions (see Volume II
for detailed explanation of assumptions):
107
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u = 1 m/sec
Cdf3 = Cd£4 = 1
Cd = 0 for uninterrupted flow
Cd „ = Cd , = 1 for signalized intersections
Cd „ = Cd , - 0 for nonsignalized intersection
(xu/Q)fl = (xu/Q)f2
(Xu/Q)f3 = (xu/Q)f4
If the receptor is near a roadway with interrrupted flow (signalized or
signed intersections), then the entire equation must be solved. If the
receptor is located near a roadway where only uninterrupted flow conditions
occur, then only the free flow portion of the equation (subscript "f"
variables) must be solved and the excess emission terms (subscript "e"
variables) within the brackets may be dropped. The worksheets automatically
perform this procedure for the different cases. The remainder of this
discussion describes each of the variables in this equation. Following
this overview, step-by-step instructions, worksheets, tables and curves
are discussed in detail.
a. Qf - Base Emission Rate from Free-Flowing Traffic - The free-flow emis-
sion rate, Qf (g/m-sec), is derived from the average vehicle cruise speed,
S, and traffic volume, V, based upon 1977 emission rates of light-duty ve-
hicles at specified ambient conditions. Average vehicle cruise speed may be
determined by observation or estimated from the type of roadway and sur-
rounding land use (see Table 13 and Figures 39 and 40). Values of Q- are
tabulated in Table 10 in the detailed instructions on applying the verifi-
cation procedures as a function of hourly lane volume and cruise speed.
*7
These were developed from application of the Modal Model.
108
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b. Qe Excess Emission Rate From Delayed Traffic - At locations where
interrupted flow occurs (signalized and signed intersections), excess emis-
sions above cruise emissions result from idling, acceleration, and deceler-
ation. The excess emissions rate, Q (g/m-sec), is a function of acceler-
ation and deceleration, the vehicle cruise speed, S, and the time of delay
at the intersection. Delay time is a function of the relative traffic vol-
umes, V, on the two intersecting streets and the G/Cy ratio (at signalized
intersections).
The Modal Model was again used here for developing the emissions charac-
teristics for both STOP-sign controlled and signalized intersections that
are utilized in the verification procedure. In applying these relation-
ships, the actual volume on the street being analyzed, and the effective
crossroad volume are used. Effective crossroad volume refers to a theo-
retical volume that reflects total impedance to the free flow of traffic
resulting from the allocation of free signal time to cross-street traffic.
This will be explained more fully in the instructions for conducting the
verification analysis.
Appropriate values for Qe are computed in step 17 of Worksheet No.5.
c. C,, and C-,. - Excess and Free-Flow Emission Correction Factors - The
—Ee E f———————————————————————————
emission rates, Q and Qf, from the Modal Model7 reflect 1977 composite
emission rates of light-duty vehicles at specified ambient conditions.
Those are the base emissions used in the guidelines. To quantify the hot
spot potential at a specific location, corrections must be made to both
free flow and excess emission rates to account for the actual calendar
year emission rates and the effects of actual vehicle mix, temperature,
altitude, percent cold-start operation, percent hot-start operation, and
state (California or other).
109
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Correction factors for both the free-flow and excess emission components
are computed separately based on Mobile I.8 These correction factors,
C., are summarized in Table 12. They are derived by taking the ratio of
the emissions of individual vehicle types at variable cold start, speed,
etc., to the emissions for a 1977, 100 percent LDV population at specified
base conditions. These correction factors by vehicle type are then mul-
tiplied by the proportion of each vehicle type, summed, multiplied by the
Modal emissions estimate, Qe and/or Qf. The general equation for calcu-
lating the entire emission correction factor is:
CE ' .
where P. = the proportion of vehicle type i (i.e., LDV, LDT, etc.); and
1 Ev
C. = —-— = the basic correction factor provided in the Guidelines
B to account for the fraction of vehicle type i's operat-
ing in the cold or hot start mode, the calendar year of
interest, and travel speed; and
where E = Mobile I emission factor for desired scenario; and
E = Mobile I8 emission factor for the base conditions of the
Modal Model.7
Calculation of the specific correction factors for cruise and excess emis-
sions is explained in greater detail in the instructions for conducting
the verification process. If the critical season temperature is different
from those presented in the table, appropriate values can be derived
through interpolation or extrapolation.
d. xu/Q ~ Normalized Concentrations - This term is a measurement of the
atmospheric dispersion of a pollutant as a function of windspeed and
direction (with respect to the emission source and receptor), and the dis-
tance separating the source and receptor. At intersections, two normalized
ff *7
No option for other scenarios exists in the Modal Model, hence the use
of the Mobile I8 emission factors.
110
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concentration terms are important. First, the normalized concentration
for the excess emission component (that is, emissions generated from
vehicles that accelerate, decelerate and idle at the intersection), must be
considered. This term, designated as (xu/Q) , is a function of vehicle
queue and delay parameters as well as windspeed and direction parameters
and source-receptor separation. Inmost instances, the CO concentration
at a receptor is maximized when (xu/Q) from the nearest street approach
is maximized.
The second term, (xu/Q),, is the normalized concentration occurring at a
receptor that results from the emissions generated by vehicles that move
through the intersection without significant slowdowns, that is, the free-
flowing traffic.
The analysis of intersections requires both the (xu/Q) and (xu/Q)f for
all approaches. To derive these values, the approach volume and cruise
speed for the approach being analyzed, and the effective crossroad volume
are utilized to derive a queue length; this is accomplished through the use
of tables provided in the guidelines. This queue length is then utilized
to derive (xu/Q)e for all approaches based on functional relationships
defined graphically in the guidelines.
e. Source-Receptor Separation Distance Correction Factors - The normalized
concentration values from both excess and free-flow emissions that the user
obtains from the graphs provided in the guidelines, reflect standard source-
receptor separation distances of 10 meters and 15 meters. Obviously, this
separation distance will not be appropriate for all locations, therefore
correction factors - Cd and Cd - are provided so that the normalized con-
centrations from both the excess and free flow source emissions can be ad-
juted to reflect the actual source-receptor separation distance. These
adjustments are made only to traffic passing over the street section
adjacent to the receptor (cross-street distances are large enough that
relatively small differences do not effect the normalized concentration
values significantly). Also, it should be noted that a factor of 1.0 is
used in analyses of street canyons.
Ill
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f. CQ hr - 8-Hour Correlation Factor - The verification procedures in-
corporate techniques based upon the calculation of 1-hour average concen-
trations of carbon monoxide from peak hour traffic volumes. Because the
8-hour standard is more often violated than the 1-hour standard, it is
necessary to provide a means for developing estimates of the 8-hour average
concentration from the calculated 1-hour average.
Analyses of air quality data from a number of monitoring stations in
several cities in the northeastern U.S. were conducted in order to deter-
mine whether a definite relationship could be established between 1-hour
average and 8-hour average concentrations. These analyses were based on
examining the relationship between maximum 1-hour average concentrations,
and maximum 8-hour average concentrations where the 8-hour averaging period
included the maximum 1-hour average. These analyses indicated that the
average ratio of 8-hour average concentrations to 1-hour average concen-
trations ranged in value from about 0.5 to 0.8, with an average of about
0.7. Further analysis of these rations with 1-hour concentrations greater
than or equal to 10 ppm indicated that this ration was slightly lower with
a range generally of from 0.6 to 0.7. Thus, a value of 0.7 was selected as
being representative of the 8-hour to 1-hour ratio.18'19
g. XB ~ Background Concentration - Studies have indicated the existence
of a background concentration of carbon monoxide occurring throughout
urban and suburban areas as a result of dispersion at or near ground level.
Determination of the actual value of the maximum expected background con-
centration involves long-term monitoring as described in References 16 and
20. The user is advised to use local measured background concentrations
wherever and whenever they are available. For cases where local monitoring
is not available a value representing a worst-case background concentration
is presented. It is based on limited analyses of data for three cities in
New England and on air quality modeling using the EPA diffusion model (APRAC)
with meteorological data covering a 1-year period. These analyses indicated
that the average maximum background concentration (8-hour average) computed
for 20 locations in each city ranged irom 2.9 mg/m3 to 5.9 ing/m3 during 1973
to 1974.18,19
112
-------
Extrapolating these figures to 1982-1983 would result in a range of
1.7 mg/m3 to 2.9 mg/m3. The higher value, 2.9 mg/m3, yields a conserva-
tive estimate of the maximum 8-hour average background concentration.
This value should be used unless data are available to develop specific
local background estimates or adjust this value to local conditions.
C. WORKSHEETS AND INSTRUCTIONS FOR HOT SPOT VERIFICATION
The following pages present detailed instructions for performing hot spot
verification. Included are separate worksheets and instructions for
analyzing signalized intersections, STOP-sign controlled intersections,
free-flowing sections of arterial streets, and expressways. It is
suggested that all signalized intersections be analyzed first, followed by
analyses of free-flowing arterials and expressway sections, and finally,
STOP-sign controlled intersections.
The first step in the process is to assemble the data required regarding
volume, vehicle type distribution, percent of vehicles operating in the
cold mode, etc., and a site sketch showing street geometry and dimensions
as well as the assumed receptor location (the required data elements are
discussed in detail in Section IV.V.I). Worksheets No. 5 and 6 are then
used to compute the likely maximum concentration based on the various data
elements and the relationships presented in Tables 9 through 12, and the
graphs shown in Figures 31 through 37. Worksheets No. 5 and 6 are each
followed by detailed instructions for completing each line on the
Worksheet.
113
-------
WORKSHEET NO. 5
CALCULATION OF CO CONCENTRATIONS AT INTERSECTIONS
1 of 3
Location:
Date:
Analysis by:
Assumptions:
Checked by:
• Analysis Year:
• Location: (a)
altitude; (c)
California; (b)
49-State, low
49-State, high altitude.
Ambient temperature:
F.
• Percent of vehicles operating in: (a) cold-start mode_
(b) hot-start mode .
• Vehicle-type distribution: LDV %; LOT %; HDV-G %;
HDV-D %; MC %.
1. Site
2. a.
b.
3. n. -
4. x. -
5. V-
identification
i - intersection approach
identification
Is approach located in a street
canyon?
Number of traffic lanes in approach i
Roadway/receptor separation (m)
Peak-hour lane volume in each approach
(veh/hr)
Main road
6. S. - Cruise speed (mph) on each approach
7. a.
b.
Type of intersection (signalized or
unsignalized)
For signalized intersections:
i) (G/Cy)i - Green time/signal cycle
ratio for approach 1
Crossroad
XX
ii) V
cross
- Effective crossroad
8. Le -
volume (veh/hr)
Queue length on approach 1 (m)
114
-------
Main road
Crossroad
9. Qf - Free-flow emission rate (g/m-sec)
10. ^T f j - Normalized concentration con-
Q f.main tribution froin free-flow emis-
sions on main roadway (10~3 m"1)
11. -^r- f - Normalized concentration
^ ' contribution from free-flow
emission on crossroad
(10-3 m'1)
12. Cdf. - Distance correction factor, free-
flow emissions
13. C f - Emissions correction factor, free-
flow emissions.
14. a.
b.
Xf Concentration contribution
' from free-flow emissions on
main road (mg/m3)
- Concentration contribution
f,cross
from free-flow emissions on
crossroad (mg/m3)
15. Xr ~ Total concentration from free-flow
emissions (mg/m )
16. CE - Emissions correction factor, excess
emissions
17. Q - Excess emission rate (g/m-sec)
18. xu r Normalized concentration contri-
Q e,i bution from excess emissions on
approach i (10~3m~1)
19. Cde. - Distance correction factor, excess
emissions
20.
e.i
. - Concentration contribution from ex-
cess emissions on approach i (mg/m )
21. x ~ Total contribution from excess emis-
sions (mg/m )
22. XF i_h ~ 1-hour average concentration
resulting from vehicle emissions
(mg/m3)
115
-------
23. XE ou - 8-hour average CO concen-
' ~ tration (mg/m3)
24. Xg g_hr - 8-hour average background con-
' centration (mg/m3)
25. XT g_h - Total CO concentration, 8-hour
' average (mg/m3)
26- X- Q , - Total CO concentration, 8-hour
i,o—nr , .
average (ppm)
116
-------
. WORKSHEET NO. 5
INSTRUCTIONS FOR COMPLETING EACH LINE
I. HEADING DATA
Location; Enter intersection street name
Date; Enter date of analysis.
Analysis by; Enter name of person performing analysis.
Checked by; Enter name of person checking the completed Worksheet.
Assumptions; Analysis year - enter calendar year reflected by the analysis.
Location - place an X on the appropriate line indicating the
type of location being considered (low altitude
is < 3500 ft).
Ambient Temperature - enter the assumed average winter
temperature for the area being con-
sidered (either 20°F or 40°F).
Percent of Vehicles - enter the proportion of vehicles operat-
ing in the cold-start mode and the pro-
portion in the hot-start mode (see
Section IV.D.3).
Vehicle-type distribution - enter the percentages of light-
duty vehicles, light-duty trucks,
heavy-duty gasoline-powered trucks,
heavy-duty diesel-powered trucks,
and motorcycles that use the streets
being analyzed (use one set of
percentages).
II. COMPUTATIONS
1. Enter the main street and cross-street names (refer to site sketch).
The main street will always be the street adjacent to the receptor.
In this connection, the assumed receptor location should be at the
point where the maximum projected concentration is likely to occur.
Guidance for identifying this point is provided in the Special In-
structions found in Section IV.D beginning on page 167.
2. a. Intersection approach identification numbers should be added to
the site sketch for reference. The designations should be made
according to the sketch as shown.
b. Enter "yes" or "no" for each approach. Guidance in identifying
street canyons is provided in Section IV.B.l.j beginning on
page 104. If approach 1 is in a street canyon, then use the
street canyon options indicated throughout the instructions that
follow.
117
-------
i
-Assigned approach
identification number
Receptor
t
©
Note that approach(l)is adjacent to the receptor, ©is on the leg opposite
approach^ (5) intersects @ before it intersects^ and(4) intersects(pbefore
it intersects (2) Again, refer to page 167.
3. Enter the number of lanes (omitting parking lanes) for each approach
(from site sketch).
4. Enter the roadway/receptor separation distance, x^; for approaches 1
and 2. This is the minimum perpendicular distance in meters from the
centerline of the traffic stream approaching the intersection to a line
parallel to the roadway drawn through the receptor site (see site
sketch).
5. Enter the peak-hour lane volume, V. (vehicles/hour), for each inter-
section approach. This is the total traffic stream volume divided
by the number of approach lanes recorded on line 3. This should
represent the busiest winter month* average weekday volume for the
year of interest (based on traffic volume data).
6. Enter the estimated roadway cruise speed, S-^ (mph), for each approach
(see Section IV.D.2 on page 174 for guidance).
7. a. Enter type of intersection (signalized, unsignalized).
b. For signalized intersections (for nonsignalized intersections
proceed to next step):
(i) Enter the ratio of green time to total signal cycle
length (G/Cy)^ allocated to approach 1. Include time
allocated for any pedestrian walk phases with no traf-
fic movement in the total cycle length. For fixed time
signals, this data will be available from design speci-
fications or from permits and records maintained by the
agency having jurisdiction over the signal. For actuated
This assumes that winter is the critical season for CO. If it is determined
that some other season is in fact the critical season, then the corresponding
traffic volumes and ambient temperature should be used.
118
-------
signals, the G/Cy for approach i can be estimated from the
equation:
0.9
G/<^ " ~~n~
V max
where G/Cy.^ is the G/Cy for approach i; and
Vmax is the highest hourly lane volume that occurs
on all approaches where traffic moves during phase i.
(ii) Determine the effective crossroad volume, V. , for approach
1 using the following equation and the volume from line 5 if
the signal is fixed time:
line
cross line 7.b.i + 0.05
iine 5
.
l
for actuated signals, V = the highest volume in line 5 3 and 5 4 ,
cro ss
8. Determine the queue length, Le (m) , that develops on approach 1 as
follows :
For signalized intersections enter the appropriate section of Table 9
based on cruise speed Sj (line 6). Enter the table using V . = Vj
(line- 5) and V = line 7 b-ii. n
cross
For imsignalized intersections use the appropriate section of
Table 11 based on cruise speed S\. Enter the table using V . =
Vi (line 5) and V = V3 or Vt» (line 5), whichever is gretter.
1 cross
9. Enter the free-flow emission rate, Qf . (g/m-sec) , for each traffic
stream using Table 10. Enter the table using line 6i (cruise speed)
and line 5 (average lane volume) for each approach. If the street
is within a street canyon, enter only the Qf . for approaches 1 and 2.
10. Enter Figure 34 at the appropriate queue length, Le (line 8) , and record
the (xu/Q)f main value using the curve designated MAIN ROAD. If the lo-
cation is within a street canyon, use Figure 35, using line 4^ and 4£.
11. Similarly, determine the normalized .concentration contribution from
free-flow emissions on the crossroad, (xu/Q)f • Use the
CROSSROAD curve of Figure 34. Enter the grapn at the same queue
length as in step 10. Omit this step for street canyons.
12. Enter the distance correction factors, Cdf^, for free-flow emis-
sions from the main roadway. Obtain these values from Figure 37.
a. Cdfi is the correction factor at x = xi (line 4).
b. Cdf2 is the correction factor for the departure lanes on leg 1,
evaluated at x = the roadway/ recreptor separation distance for
the departure stream; This value is X2 (line 4)2-
Note: For screet canyons, assume a value~ of 1.0.
119
-------
13. Compute the free-flow emissions correction factor, CF-, reflecting
the assumed calendar year, cruise speed, percentage or vehicles
operating in the cold-start and hot-start modes, ambient temperature,
and vehicle-type distribution. This is derived from the following
equation:
CEf = PLDV CLDV + PLDT °LDT + PMC CMC + PHDG CHDG + PRDD CHDD
where PTTW = fraction of light-duty vehicles (from heading data);
PTn = fraction of light-duty trucks (from heading data);
LiD i.
P = fraction of motorcycles (from heading data);
P = fraction of heavy-duty, gasoline-powered trucks
(from heading data);
PHDD = fracti°n °f- heavy-duty, diesel-powered trucks
(from heading data);
= correcti°n factor reflecting the assumed calendar year,
cruise speed, percentage of vehicles operating in the
cold start mode, percentage of vehicles operating in
the hot-start mode, and ambient temperature for light-
duty vehicles (obtained from Table 12);
= correction factor reflecting the assured calendar year,
cruise speed, percentage of vehicles operating in the
cold-start mode, percentage of vehicles operating in the
hot-start mode, and ambient temperature for light-duty
trucks (obtained from Table 12);
C„ = correction factor reflecting the assumed calendar year,
cruise speed, percentage of vehicles operating in the
cold-start mode, percentage of vehicles operating in the
hot-start mode, and ambient temperature for motorcycles
(obtained from Table 12);
= correcti°n factor reflecting the assumed calendar year and
cruise speed for heavy-duty, gasoline-powered trucks
(obtained from Table 12) ;
'"'HDD = correcti°n factor reflecting the assumed calendar year
and cruise speed for heavy-duty, diesel-powered trucks
(obtained from Table 12).
14. Compute the concentration contribution from free-flow emissions, xf,
from each roadway
f,main
a- X£ „„„._ = [(line 10) (line 13)1 Kline Saline 9) i (line 12) l +
(line 3) 2 (line 9)2 (line 12) 2
120
-------
b. Xf • [(line llXline 13)] [(line 3)3(line 9)3
(line 3)it (line 9)i» ]
cross
Note: for street canyons, x* > need not be computed.
l , cross r
15. Sum line 14a and 14b entries to obtain total contribution from
free-flow emissions, xf.
16. Compute the excess emissions correction factor, CE , reflecting the
assumed calendar year, idle (speed 0), percentage of vehicles operat-
ing in the cold- or hot-start mode, ambient temperature, and vehicle
type distribution. This is derived from the following equation:
CEe = PLDV CLDV-0 + ?LDT °LDT-0 * PMC CMC-0 + ?HDG CHDG-0 + PHDD CHDD-0
where PLDV> PLDT» PMC» ^Q and pyDD are as defined in item 13, above; and
CLDV-0' CLDT-0' CMC-0' CHDG-0' and CHDD-0 are the correction
factors from Table 12 reflecting the assumed calendar year, speed
of 0, percentages of cold- and hot-start operation, and ambient
temperature for each vehicle type.
17. Compute the excess emission rate, Q (g/m-sec), from:
Qe -
-------
a. The contribution from approach 1:
Enter Figure 31 at the appropriate queue length, Le (line 8),
to obtain (xu/Q) . . Multiply this value by the number of
e,l
traffic lanes in approach 1 (line 3), and record result. For
street canyons, the procedure is the same except use Figure 35
instead of 31.
b. The contribution from approach:
Enter Figure 32, curve 2, at the same Le, used in part (a),
(line 8), to obtain (xu/Q)e 2« Multiply this value by the
»
number of traffic lanes in approach 2 (line 3), and record
result. For street canyons, assume (xu/Q)e 2 = 0.
c. The contribution from approach 3:
Signalized intersections - Enter Figure 32, Curve 3 at
Le (line 8) to obtain (xu/Q)e 3- Multiply by the number of
traffic lanes in approach 3 (line 3), and record result.
For street canyons and unsignalized intersections,
(xu/Q)e,3 " 0.
d. The contribution from approach 4:
Signalized intersections - Enter Figure 32, Curve 4 at
Le (line 8 ) to obtain (xu/Q)e 4. Multiply by the number of
traffic lanes in approach 4 (line 3) and record result. For
street canyons and unsignalized intersections, (xu/Q)e 4 = 0.
L9. Determine the distance correction factors for the excess emissions
contributions, Cde^:
a. Approach 1: obtain Cdei from Figure 36 at the appropriate
roadway/receptor separation distance x^ (line 4) .
Note: For street canyons, Cdei = 1.0.
b. Approach 2: compute Cd&2 by dividing the value obtained from
Figure 36 at the appropriate distance X£ (line 4) by 0.79:
Cde (at
c. Approach Sf^Cde^- 1 for signalized intersections and Cde3.u- 0
for nonsignalized intersections.
20. Compute the concentration contribution from excess emissions, xe>
for each approach i, using the following equation:
X., - (QF) (4?)^ (Cde).
G J. JQj \^ " J. J_
where Q_ = the excess emission rate from line 17;
£.
= the normalized concentration contribution from excess
Q/
ei emissions from line 18; and
= the distance correction from line 19.
122
-------
21. Sum all line 20 entries to obtain the total concentration, X >
resulting from excess emissions at the intersection.
22. Compute the 1-hour average concentration resulting from vehicle
emissions, XF i i, » by summing line 21 and line 15.
23. Multiply line 22 by 0.7 to obtain the highest expected 8-hour
average concentration resulting from vehicle emissions.
24. Enter 8-hour average background CO concentration in mg/m3. Use
2.9 mg/m3 if specific local background estimates are not avail-
able and see Section V.B.
25. Sum lines 23 and 24 to obtain maximum expected 8-hour average con-
centration in the vicinity of the intersection (mg/m3).
26. Multiply line 25 by 0.87 to convert the CO concentration from
mg/m3 to ppm.
123
-------
WORKSHEET NO. 6
CALCULATION OF CO CONCENTRATIONS ALONG ROADWAYS
WHERE UNINTERRUPTED FLOW PREVAILS
Location:
Date:
Analysis by:
Assumptions:
Checked by:
Analysis Year:
Location: (a)_
altitude; (c)
California; (b)
49-State, low
49-State, high altitude.
• Ambient temperature:
'F.
• Percent of vehicles operating in: (a) cold-start mode %;
(b) hot-start mode %.
• Vehicle-type distribution: LDV %, LOT %; HDV-G %;
HDV-D ; MC %.
• Street Canyon:
1. Site identification
Yes;
No.
2. Traffic stream identification
3. V - Peak-hour lane volume for each traffic
stream (veh/hr)
4. x - Roadway/receptor separation (m)
5. n. - Number of lanes per traffic stream
6. S - Cruise speed (mph) for each traffic
stream
7. Qf, - Free-flow emission rate (g/m-sec)
gt p^-J - Normalized concentration contri-
\ / bution from each traffic stream
(ID'3 m-1)
9. C , - Emission correction factor
LJ L
10. x., - Concentration contribution from each
traffic stream (mg/m3)
124
-------
Worksheet No. 6 (continued).
11. xp I r. - 1-hour average CO concentration resulting
' ~ r from vehicle emissions (mg/m3)
12. x^ oi. - 8-hour average CO concentration (mg/m3)
E, o—hr
13- XT> Q u - 8-hour average background concentration
a, o—nr / / 3\
' (mg/m^)
1^' Xm o t, - Total CO concentration, 8-hour average
i. o—nr / / Q\
' (mg/m3)
15. XT o v,>- ~ Total CO concentration, 8-hour average
j., o—nr / x
(ppm)
125
-------
WORKSHEET NO. 6
INSTRUCTIONS FOR COMPLETING EACH LINE
I.
II.
HEADING DATA
Location: Enter facility name and general location (e.g., Mystic Parkway
between exits 60 and 61) .
Date:
Enter date of analysis.
Analysis by; Enter name of person performing analysis.
Checked by; Enter name of person checking the completed Worksheet
Assumptions: Analysis year - enter calendar year reflected by the analysis.
Location - place an X on the appropriate line indicating the
type of location being considered (low altitude
is < 3500 ft).
Ambient Temperature - enter the assumed average winter
temperature for the area being con-
sidered (either 20°F or 40°F).
Percent of Vehicles - enter the proportion of vehicles operat-
ing in the cold-start mode and the pro-
portion in the hot-start mode (see
Section IV.D.3 on page 174).
Vehicle-type distribution - enter the percentages of light-
duty vehicles, light-duty trucks
heavy-duty gasoline-powered trucks,
heavy-duty diesel-powered trucks,
and motorcycles that use the streets
being analyzed (use one set of
percentages).
place an X on the appropriate line (see
Section IV.B.I on page 104 for guidance
in identifying street canyons).
Street Canyon:
COMPUTATIONS
1. Enter the facility name.
2. Enter the direction of flow for each traffic stream (e.g., north-
bound, eastbound, etc.). Again, approach 1 shall be adjacent to the
assumed receptor.
3. Enter the peak-hour traffic volume, V., for each traffic stream
(winter, busiest month, estimates or observed).
4. Enter the traffic stream/receptor separation distance, x . This is
the perpendicular distance in meters from the centerline of each
traffic stream to the receptor location. Minimum distance = 10 meters.
126
-------
5. Enter the number of lanes, n., per traffic stream (see site sketch).
6. Enter the average cruise speed, S. (mph) , for each traffic stream
(for guidance, see Section IV. D.).
7. Determine the free-flow emission rate, Qf. (g/m-tsec) , for each traffic
stream from Table 9. Enter the table using line 6, cruise speed and
(line 3) * (line 5), average lane volumes.
8. Determine the normalized concentration contribution (xu/Q)f ±
each traffic stream using Figure 33. Enter the graph at the appro-
priate roadway/receptor separation distance x. (line 4) . If the
facility is located within a street canyon, use Figure 35.
9. Compute the free-flow emissions correction factor, C_,f, reflecting
the assumed calendar year, cruise speed, percentage or vehicles
operating in the cold-start mode, percentage of vehicles operating
in the hot-start start mode, ambient temperature, and vehicle-type
distribution; CEf is derived using the equation shown in Item 13 of
the instruction sheet explaining Worksheet No. 5.
10. Compute the concentration contribution, x. , from each stream as
follows:
- X± • (line 7)± (line 8) ± (line 9)
11. Compute the 1-hour average CO concentration resulting from vehicle
emissions by summing the line 10 concentrations.
/
12. Multiply line 11 by 0.7 to obtain the highest expected 8-hour
average concentration resulting from vehicle emissions (mg/m3) .
13. Enter the 8-hour average background CO concentration in mg/m3.
Use the 2.9 mg/m3 if specific local background estimates are not
available.
14. Sum line 15 and line 16 to obtain the maximum expected 8-hour
average concentration in the vicinity of the roadway (mg/m3) .
15. Multiply line 17 by 0.87 to convert total CO concentration to ppm.
127
-------
Table 9.
TOTAL QUEUE EMISSIONS, (QqT), CRUISE COMPONENT EMISSION, (Q0c)> AND QUEUE
AS A FUNCTION OF MAJOR AND CROSS-STREET VOLUMES AND CRUISE SPEED - SIGNAL
LENGTH
SIGNALIZED
INTERSECTIONS
00
Cro«e-«tre«t
effective loo*
volum (v«h/hr)
1*00
1)00
1200
1100
1000
900
800
Clement
V
V
Queue
V
V
Queue
V
V
Queue
V
V
Queue
V
V
Queue
V
V
Queue
V
V
Queue
ttajor itreet voluae - (•••u«*d cruUe loOTd it 15 ai/far)
100
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
700
-
-
-
0.05141
0.00004
1901.4
0.0483)
0.00019
367.9
0.04542
0.00039
173.2
0.04262
0.00065
103.9
0.04O05
0.00096
70.2
0.03775
0.00130
51.0
300
0.04181
0.00013
796.5
0.04023
0.00030
347.2
0.03873
0.00050
205.7
0.3732
0.00073
139.0
0.03601
0 . 00099
101.2
0.03481
0.00127
77.3
0.03373
0.00158
60.9
400
0.01912
-
-
0.03504
0.00020
670.4
0.03415
0.00043
314.2
0.03331
0.00068
197.4
0.03253
0.00094
139.4
0.03181
0.00123
105.0
0.03114
0.00153
82.3
500
-
-
-
0.01828
-
-
0.03081
0.00024
698.6
0.03029
0.00050
333.4
0.02980
0.00077
211.9
0.02933
0.00106
151.1
0.02888
0.00136
114.5
600
-
-
-
-
-
-
0.01609
-
-
0.02765
0.00027
757.5
0.02736
0.00055
362.9
0.02706
0.00083
231.0
0.02676
0.00113
164.5
700
-
-
-
-
-
-
-
-
-
0.01531
-
-
0.02504
0.00028
826.6
0.02488
0.00058
395.2
0.02470
0.00087
250.5
800
-
-
-
-
-
-
-
-
-
-
-
-
0.01306
-
-
0.02274
0.00030
899.1
0.02268
0.00060
427.4
900
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
0.02065
0.00030
971.8
1000
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
0.01003
-
-
1100
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
~
1200
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
1300
-
-
-
-
-
•
-
-
-
-
~
~
-
-
-
-
~
-
-
~
~
14OO
-
-
~
-
~
~
-
*
~
-
~
~
-
~
~
-
~
~
-
~
"
-------
Table 9 (continued).
TOTAL QUEUE EMISSIONS, (QqT), CRUISE COMPONENT EMISSION, (QQC), AND
QUEUE LENGTH AS A FUNCTION OF MAJOR AND CROSS-STREET VOLUMES AND
CRUISE SPEED - SIGNALIZED INTERSECTIONS
to
Croaa-atreet
effective laoe
volume (veh/hr)
700
600
500
400
300
200
100
Element
V
V
Queue
V
V
Queue
V
Qoeoe
V
V
Queue
V
V
Queue
V
V
Queue
V
Queue
Major atreec volu« - (aaaoBed cniiae speed ia 15 «i/hr)
100
-
0.04534
0.00051
66.8
0.02441
0.00084
40.0
0.01302
0.00082
40.0
0.00851
0.00078
40.0
0.00601
0.00071
40.0
0.00384
0.00056
40.0
200
0.03470
0.00163
40.0
0.02602
0.00159
40.0
0.02006
0.00154
40.0
0.01568
0.00146
40.0
0.01216
0.00134
40.0
0.00893
0.00117
40.0
0.00544
0.00086
40.0
300
0.03278
0.00191
49.1
0.03192
0.00226
40.1
0.02561
0.00216
40.0
0.02038
0.00202
40.0
0.01579
0.00182
40.0
0.01142
0.00153
40.0
0.00686
0.00109
40.0
400
0.03051
0.00184
66.0
0.02988
0.00217
53.8
0.02921
0.00250
44.0
0.02540
0.00253
40.0
0.01948
0.00225
40.0
0.01392
0.00186
40.0
0.00838
0.00130
40.0
500
0.02842
C. 00166
89.8
0.02793
0.00198
71.9
0.02736
0.00230
58.0
0.02665
0.00261
46.5
0.02351
0.00267
40.0
0.01666
0.00218
40.0
0.01012
0.00151
40.0
600
0.02643
0.00143
124.2
0.02605
0.00174
96.6
0.02559
0.00205
76.3
0.02499
0.00236
60.2
0.02418
0.00265
46.6
0.01984
0.00250
40.0
0.01217
0.00172
40.0
700
0.02449
0.00118
177.2
0.02423
0.00148
132.4
0.02388
0.00179
101.4
0.02341
0.00209
78.2
0.02276
0.00238
59.4
0.02187
0.00262
43.3
0.01464
0.00195
40.0
800
0.02258
0.00090
268.6
0.02243
0.00121
187.8
0.02220
0.00151
137.9
0.02186
0.00181
103.1
0.02139
0.00210
76.5
0.02077
0.00234
54.7
0.01768
0.00219
40.0
900
0.02066
0.00061
457.6
0.02062
0.00092
283.9
0.02051
0.00123
193.0
0.02013
0.00153
139.5
0.02004
0.00181
100.4
0.01968
0.00206
70.0
0.01937
0.00221
44.4
1000
0.01870
0.00031
1042.1
0.01878
0.00062
484.0
0.01880
0.00093
294.7
0.01876
0.00124
197.1
0.01867
0.00153
135.6
0.01857
0.00178
91.5
0.01870
0.00194
56.6
1100
0.00852
0.01686
0.00032
1107.7
0.01701
0.00'J63
504.4
0.01712
0.0009*
298.8
0.01722
0.00124
191.8
0.01739
0.00150
123.5
0.01795
0.00168
73.7
1200
-
0.00789
0.01512
0.00032
11*4. 9
0.01511
0.0006*
515.5
0.01S66
0.00094
292.6
0.01608
0.00122
175.3
0.01708
0.00141
99.2
1300
-
-
0.00694
-
0.01347
0.00032
1208.3
0.01393
0.00064
511.1
0.01460
0.00093
269.6
0.01601
0.00115
140.7
1400
-
-
-
-
0.00492
0.01196
0.00032
1226.4
0.01284
0.00063
479.5
0.01465
0.00088
217.3
-------
Table 9 (continued).
TOTAL QUEUE EMISSIONS, (QqT), CRUISE COMPONENT EMISSION, (Qqc), AND
QUEUE LENGTH AS A FUNCTION OF MAJOR AND CROSS-STREET VOLUMES AND
CRUISE SPEED - SIGNALIZED INTERSECTIONS
to
o
CroM-«tr**t
volu-r Ueh/hr)
1400
1300
1200
1100
1000
900
BOO
El—.,
V
V
Queue
V
V
Que°e
V
V
OJ»~
V
V
q«w
V
V
Ojroe
V
V
Que~
V
V
Q—«
100
-
~
-
-
-
_
-
-
-
-
-
-
-
-
-
-
-
-
-
-
200
-
-
-
0.05146
0.00004
1901.4
0.04863
0.00023
367.9
0.04598
0.00049
173.2
0.04354
0.00081
103.9
0.04139
0.00118
70.2
0.03959
0.00161
51.0
300
O.O4199
0.00016
796.5
0.4065
O.O0036
J47.2
0.03943
0.00061
205.7
0.03834
0.00089
139.0
0.03739
0.00121
101.2
0.03660
0.00157
77.3
0.03596
0.00195
60.9
400
0.01912
-
-
0.03532
0.00025
670.4
0.03475
0.00053
314.7
0.03426
0.00083
197.4
0.03386
0.00116
139.4
0.03354
0.00151
105.0
0.03329
0.00188
82.3
H
500
-
0.1812
-
-
0.03116
0.00030
698.6
0.03100
0.00062
333.4
0.03089
0.00095
211.9
0.03082
0.00130
151.1
0.03078
0.00167
114.5
*jor itreec
600
-
-
-
-
0.01609
-
_
0.02803
0.00033
757.5
0.02812
0.00067
362.9
0.02823
0.00103
231.0
0.02834
0.0013*
164.5
.01-. - (
700
-
-
-
-
-
-
-
-
0.01531
-
-
0.02544
0.00035
826.6
0. 02 569
0.00071
395.2
0.02593
0.00108
250.5
••HMcd cm
800
-
~
-
-
-
~
-
-
-
-
0.01306
-
-
0.02316
0.00036
899.1
0.02352
0.00073
427.4
ise speed i
900
-
-
-
-
-
-
-
-
-
-
-
-
.
-
-
0.02108
0.00038
971.8
20 .i/br)
1000
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
0.01003
-
~
1100
_
-
-
-
-
-
-
-
•
~
-
-
-
j
-
-
-
~
1200
-
-
-
-
-
-
-
-
-
*
-
"
-
-
-
-
-
-
-
-
~
1300
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
1400
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-------
Table 9 (continued).
TOTAL QUEUE EMISSIONS, (Q
-------
Table 9 (continued).
TOTAL QUEUE EMISSIONS, (QQT), CRUISE COMPONENT EMISSION, (QgC), AND
QUEUE LENGTH AS A FUNCTION OF MAJOR AND CROSS-STREET VOLUMES AND
CRUISE SPEED - SIGNALIZED INTERSECTIONS
ts3
Cro»«-»cre*t
effective' lue
1400
1300
1200
1100
1000
900
800
E leant
V
V
Queue
V
Queue
V
V
Queue
V
V
Queue
V
V
Queue
V
V
Queue
V
V
Queue
Major «treet voltBt - (a*«iK«d craice ipeed is 25 m/hr)
100
_
~
-
-
-
-
-
;
200
_
0.05152
0.00005
1901.4
0.04894
O.OO027
367.9
0.04662
0.00058
173.2
0.04460
0.00096
103.9
0.04294
0.00140
70.2
0.04170
0.00191
51.0
300
0.04220
0.00019
796.5
0.04112
0.00043
347.2
0.04023
0.00072
205.7
0.03951
0.00106
139.0
0.03899
0. 00144
101.2
0.03866
0.00186
77.3
0.03852
0.00232
60.9
400
0.01912
0.03565
0.00030
670.4
0.03545
0.00063
314.7
0.03536
0.00099
197.4
0.03539
0.00138
139.4
0.03552
0.00180
105.0
0.03576
0.00224
82.3
500
;
0.01828
-
0.03155
0.00036
698.6
0.03181
0.00073
333.4
0.03214
0.00113
211.9
0.03254
0.00155
151.1
0.03298
0.00198
114.5
600
;
~
-
0.01609
0.02846
0.00039
757.5
0.02901
0.00080
362.9
0.02958
0.00122
231.0
0.03017
0.00165
164.5
700
;
:
-
-
0.01531
0.02590
O.OO042
826.6
0.02662
0.00084
395.2
0.02734
0.00128
250.5
800
;
-
-
-
0.01306
0.02364
0.00043
899.1
0.02448
O.OOO87
427.4
900
-
-
-
-
;
-
0.02157
0.00045
971.8
1000
;
-
-
-
-
-
-
0.01003
1100
_
~
-
-
-
;
~
-
1200
;
:
-
-
-
:
-
-
1300
:
~
-
-
-
;
;
-
1400
_
:
-
-
-
-
;
-
-------
Table 9 (continued). TOTAL QUEUE EMISSIONS, (QQT), CRUISE COMPONENT EMISSION, (Qgc), AND
QUEUE LENGTH AS A FUNCTION OF MAJOR AND CROSS-STREET VOLUMES AND
CRUISE SPEED - SIGNALIZED INTERSECTIONS
u>
u>
Cross-street
effective lane
voloe (v«h/hr)
700
600
500
400
300
200
100
Element
V
V
Queue
V
V
Major street voliase - (assuaed cruise speed is 25 ai/hr)
100
-
-
-
0.04688
0.00075
Queue ) 66.8
V
V
Queue
V
V
Queue
V
V
Queue
V
V
Queue
V
V
Queue
0.02694
0.00123
40.0
0.01548
0.00119
40.0
0.01085
0.00114
40.0
0.00815
0.00103
40.0
0.00553
0.00082
40.0
200
0.03943
0.00239
40.0
0.03034
0.00233
40.0
0.02471
0.00225
40.0
0.02009
0.00214
40.0
0.01622
0.00197
40.0
0.01245
0.00170
40.0
0.00803
0.00125
40.0
300
0.03856
0.00280
49.1
0.03876
0.00331
40.1
0.03214
0.00316
40.0
0.02648
0.00295
40.0
0.02129
0.00266
40.0
0.01604
0.00224
40.0
0.01015
0.00159
40.0
400
0.03607
0.00269
66.0
0.03642
0.00317
53.8
0.03676
0.00366
44.0
0.03305
0.00371
40.0
0.02628
0.00329
40.0
0.01954
0.00272
40.0
0.01231
0.00191
40.0
500
0.03344
0.00243
89.8
0.03390
0.00289
71.9
0.03429
0.00336
58.0
0.03454
0.00382
46.5
0.03157
0.00390
40.0
0.0232*
0.00319
40.0
0.01468
0.00221
40.0
600
0.03076
0.00210
124.2
0.03132
0.00255
96.6
0.03179
0.00300
76.3
0.03212
0.00345
60.2
0.03218
0.00388
46.6
0.02739
0.00365
40.0
0.01738
0.00252
•0.0
700
0.02805
0.00172
177.2
0.02871.
0.00217
132.4
0.02928
0.00262
101.4
0.02972
0.00306
78.2
0.02993
0.00347
59.4
0.02978
0.00383
43.3
0.02052
0.00285
40.0
. 800
0.02530
0.00132
268.6
0.02608
0.00177
187.8
0.02677
0.00221
137.9
0.02734
0.00265
103.1
0.02773
0.00307
76.5
0.02783
0.00342
54.7
0.02428
0.00320
40.0
900
0.02251
0.00090
457.6
0.02340
0.00135
283.9
0.02422
0.00180
195.0
0.02494
0.00223
139.5
0.02552
0.00265
100.4
0.02590
0.00301
70.0
0.02604
0.00323
44.4
1000
0.01964
0.00046
1042.1
0.02066
0.00091
484.0
0.02162
0.00137
294.7
0.02250
0.00181
197.1
0.02328
0.00223
135.6
0.02395
0.00260
91.5
0.02456
0.00284
56.6
1100
0.00852
-
-
0.01782
0.00046
1107.7
0.01892
0.00092
504.4
0.01996
0.00138
298.8
0.02095
0.00181
191.8
0.02192
0.00219
123.5
0.02302
0.00245
73.7
. 1200
-
-
-
0.00789
-
-
0.01609
0.00047
1164.9
0.01730
0.00093
515.5
0.01850
0.00137
292.6
0.01975
0.00178
175.3
0.02135
0.00207
99.2
1300
-
-
-
-
-
-
0.00694
-
-
0.01445
0.00047
1208.3
0.01585
0.00093
511.1
0.01740
0.00136
269.6
0.01948
0.00168
140.7
1400
-
-
-
-
-
-
-
-
-
0.004*2
-
-
0.012*4
0.00048
1226.4
0.01475
0.000*2
479.5
0.01731
0.00129
217.3
-------
Table 9 (continued).
TOTAL QUEUE EMISSIONS, (QQT>, CRUISE COMPONENT EMISSION, (Qqc), AND
QUEUE LENGTH AS A FUNCTION OF MAJOR AND CROSS-STREET VOLUMES AND
CRUISE SPEED - SIGNALIZED INTERSECTIONS
Crosc-Btmc
effective lue
vol«« (vch/hr)
1100
1300
12OO
1100
1000
900
800
Clone
V
V
Queue
V
V
Queue
V
V
Queue
V
V
Queue
V
V
Queue
V
V
Queue
V
"".,
Ifajor »trect volwe - (••suved cmi«e »pc«d im 30 Hi/hr)
100
-
-
200
-
-
- !
0.05159
-
-
-
-
-
-
-
-
-
0.00006
1901.4
0.04929
0.00032
367.9
0.04737
0.00068
173.2
0.04585
0.00113
! 103.9
-
-
0.0447
0.00166
70.2
I
0.04418
0.00225
51.0
300
0.04244
0.00022
796.5
0.04168
0.00051
347.2
0.04117
0.00086
205.7
0.04090
0.00125
139.0
0.04086
0.00170
101.2
0.04108
0.00220
77.3
0.04153
0.00273
60.9
4OO
0.01912
-
-
0.03604
0.00035
670.4
0.03626
0.00074
31*. 7
0.03665
0.00117
197.4
0.03718
0.00163
139.4
0.03786
0.00212
105.0
0.03867
0.0026*
82.3
500
-
-
-
0.01828
-
-
0.02101
0.00042
698.6
0.03277
0.00087
333.4
0.03362
0.0013*
211.9
0.03455
0.00183
151.1
0.03556
0.00234
114.5
600
-
-
-
-
-
-
0.01609
-
-
0.02897
0.000*6
757.5
0.03OO*
0.0009*
362.9
0.03117
0.001*4
231.0
0.03232
0.00195
164.5
700
-
-
-
-
-
-
-
-
-
0.01531
-
-
0.02644
0.00049
826.6
0.02772
0.00099
395.2
0.02901
0.00151
250.5
800
-
-
-
-
-
-
-
-
-
-
-
-
0.01306
-
-
0.02*20
0.00051
899.1
0.02562
0.00103
427.4
900
-
-
-
1000
-
-
-
i
-
-
-
-
-
-
-
-
-
-
i
-
-
-
-
-
-
-
-
i
-
-
0.02215
0.00053
971.8
-
-
-
0.01003
-
-
1100
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
1200
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
1300
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
- .
-
-
-
1*00
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-------
Table 9 (continued).
TOTAL QUEUE EMISSIONS, (QQT), CRUISE COMPONENT EMISSION, (Qgc), AND
QUEUE LENGTH AS A FUNCTION OF MAJOR AND CROSS-STREET VOLUMESAND
CRUISE SPEED - SIGNALIZED INTERSECTIONS
CO
Cross-street
effective Ijoe
volute (veb/hr)
700
60O
500
400
3OO
2OO
1OO
Elescot
V
V
Queue
V
It-
V
Queue
V
V
Queue
V
V
Queue
V
V
Queue
V
V
Queue
100
-
0.04785
0.00088
66.8
0.02854
0.00145
40.0
0.01703
0.00141
40.0
0.01233
O.OOI34
40.0
0.00949
0.00122
40.0
0.00660
0.00097
40.0
200
0.04273
0.00282
40.0
0.03387
0. 00275
40.0
0.02763
0.00266
40.0
0.02287
O.O0252
40.0
0.01878
0.00232
40.0
0.01466
0.00201
40.0
0.00965
O.O0148
40.0
300
0.04221
0.00331
49.1
0.04307
0.00391
40.1
0.03625
0.00373
40.0
0.03032
0.00349
40.0
0.02475
0.00314
40.0
0.01896
0.00265
40.0
0.01222
0.00188
40.0
400
0.03958
0.00318
66.0
0.04055
0.000374
53.8
0.04152
O.O0432
44.0
0.03787
0.00438
40.0
0.03056
0.00389
40.0
0.02308
0.00321
40.0
0.01479
0.00225
40.0
"•
50O
0.03661
0.00287
89.8
0.03766
0.00342
71.9
0.03866
0.00396
58.0
0.03951
0.00451
46.5
0.03664
O.OO461
40.0
0.02738
0.00376
40.0
0.01756
0.00261
40.0
or street v
600
0.03349
0.00248
124.2
0.03463
0.00301
96.6
0.03569
0.00355
76.3
0.03660
0.00407
60.2
0.03722
O.O0458
46.6
0.03214
0.00431
40.0
0.02066
0.00298
40.0
>lu»e - (ass
700
0.03029
0.00203
177.2
0.03153
0.00256
132.4
0.03269
0.00309
101.5
0.03370
0.00361
78.2
0.03445
O.OO410
59.4
0.03477
0.00453
43.3
0.02423
0.00336
40.0
Med cruise
800
0.02702
0.00156
268.6
0.02837
0.00209
187.8
0.03976
O.OO261
137.9
0.03079
0.00313
103.1
0.03171
0.00362
76.5
0.03229
0.00404
54.7
0.02844
0.00378
40.0
•peed is 30 I
900
0.02367
0.00106
457.6
0.02515
0.00159
283.9
0.02656
0.00212
195.0
0.02785
0.00264
139.5
0.02897
0.00313
100.4
0.02982
O.O03S6
70.0
0.03O23
0.00381
44.4
•i/hr)
1000
0.02023
0.00054
1042.1
0.02185
0.00108
484.0
0.02339
0.00161
294.7
0.02485
0.00214
197.1
0.02618
0.00264
135.6
0.02733
0.00307
91.5
0.02825
0.00335
56.6
1100
0.00852
-
-
0.01842
0.00055
1107.7
0.02012
0.00109
504.4
0.02175
0.00162
298.8
0.02330
0.00213
191.8
0.02477
0.00259
123.5
0.02621
0.00290
73.7
1200
-
-
-
0.00789
-
-
0.01670
0.00055
1164.9
0.01851
0.00110
515.5
0.01019
O.OC162
292.6
0.02207
0.00210
175.3
0.02404
0.00244
99.2
1300
-
-
-
-
-
—
0.00694
-
-
0.01507
0.00045
1108.2
0.01707
0.00110
511.1
0.01916
0.00160
269.6
O.O2167
0.00199
140.7
1400
-
-
-
-
-
-
-
-
-
0.00492
-
-
0.01356
0.00056
1226.4
0.01S95
0.00109
479.5
0.01(99
0.00152
217.3
-------
Table 9 (continued).
TOTAL QUEUE EMISSIONS, (QQT>, CRUISE COMPONENT EMISSION, (Qqc), AND
QUEUE LENGTH AS A FUNCTION OF MAJOR AND CROSS-STREET VOLUMES AND
CRUISE SPEED - SIGNALIZED INTERSECTIONS
Crotl-ttreet
effective lane
volune (veh/hr)
1«K>
1300
1200
1100
1000
900
800
Eleieot
V
Ha
100
-
V
Queue '
V
V
Queue
V
V
Queue
V
«QC
Queue
V
V
Queue
V
V
Queue
V
V
Queue
~
-
-
-
-
-
200
-
_
0.05167
0.00007
1901.4
0.04971
0.00038
367.9
0.04826
0.90081
173.2
0.04733
0.00134
103.9
0.04694
0.00197
70.2
0.04713
0.00268
51.0
300
0.04273
0.00027
796.5
0.04235
0.00061
347.2
0.04229
0.00102
205.7
0.04254
0.00149
139.0
0.04310
0.00203
101.2
0.04396
0.00262
77.3
0.04511
0.00325
60.9
400
0.01912
_
0.03650
0.00042
670.4
0.03724
0.00088
314.7
0.03818
0.00139
197.4
0.03932
0.00194 .
139.4
0.04064
0.00252
105.0
0.04212
0.00314
82.3
500
-
_
0.01828
0.03256
0.00050
698.6
0.03390
0.00103
333.4
0.03537
0.00159
211.9
0.03695
0.00218
151.1
0.03863
0.00279
114.5
600
-
_
:
0.01609
"0.02958
0.00d55
757.5
0.03128
0.00112
362.9
0.03306
0.00171
231.0
0. 034 88
0.00232
164.5
700
-
_
;
-
0.01531
0.027080
0.00058
826.6
0.02902
0.00118
395.2
0.03098
0.00180
250.5
800
-
_
;
-
-
0.01306
0.02*87
0.00061
899.1
0.02697
0.00123
427.4
900
-
:
_
•-
-
-
-
0.02284
0.00063
971.8
ti/hr)
1000
-
_
;
-
-
-
-
0.01003
1100
-
1200
-
!
-
-
-
-
-
-
-
-
-
-
-
-
1300
-
_
;
-
-
- -
-
-
1400
-
;
-
-
-
;
-
-
u>
-------
Table 9 (continued).
TOTAL QUEUE EMISSIONS, (QQT), CRUISE COMPONENT EMISSION, (Qgc), AND
QUEUE LENGTH AS A FUNCTION OF MAJOR AND CROSS-STREET VOLUMES AND
CRUISE SPEED - SIGNALIZED INTERSECTIONS
Cross-street 1
effective Isne
volu»e (veh/hr» Element
700 I 0^—
IW
< Queue
600 : Q
500
400
300
200
100
V
Queue
V
Queue
V
V
Queue
V
V
Queue
V
«QC
Queue
V
V
Queue
Hsjor street *olu*e - (assumed cruise speed is 35 sa/hr)
100
.
-
0.04901
0.00105
66.8
0.03044
0.00172
40.0
0.01888
0.00168
40.0
0.01408
0.00160
40.0
0.01109
0.00145
40.0
0.00787
0.00115
40.0
200
0.04643
0.00336
300
400
0.04654 0.04374
0.00394 ' 0.00379
40.0
0.03747
0.00327
40.0
0.03111
0.00316
40.0
0.02617
0.00300
40.0
0.02182
0.00276
40.0
0.01730
0.00239
40.0
0.01159
0.00176
40.0
49.1 66.0
0.04819 0.04545
0.00465 i 0.00446
40.1 i 53.8
0.04114 i 0.04718
)
O.OO444
40.0
0.03488
0.00415
40.0
0.02887
0.00374
40.0
0.02242
0.00315
40.0
0.00514
44.0
0.04361
0.00521
40.0
0.03565
0.00463
40.0
0.02729
0.00382
40.0
0.01469 i 0.01774
0.00224
4O.O
0.00268
40.0
500
0.04037
0.00342
89.8
0.04214
0.00406
71.9
0.04385
0.00472
58.0
0.04542
0.00537
46.5
0.04267
0.00548
40.0
0.03231
0.00448
40.0
0.02098
0.00311
40.0
600
0.03674
0.00295
Ii4.2
0.03857
0.00358
96.6
0.04034
0.00422
76.3
0.04194
0.00485
60.2
0.04322
0.00545
46.6
0.03779
0.00513
40.0
0.02456
0.00354
40.0
700
0.03295
0.00242
177.2
0.03489
0.00305
132.4
0.03674
0.00368
101.4
0.03843
0.00430
78.2
0.03983
0.00488
59.4
0.04070
0.00539
43.3
0.02863
0.00400
40.0
800
0.02906
0.00185
268.6
0.03111
0.00248
187.8
0.03307
0.00311
137.9
0.03489
0.00373
103.1
0.03645
0.00431
76.5
0.03758
0.00481
54.7
0.03339
0.00449
40.0
900
1000
0,02506 ' 0.02094
0.00126 | 0.00064
457.6 1042.1
0.02724 0.02326
0.00189 0.00128
283.9 484.0
0.02933
0.00252
195.0
0.03130
0.00314
139.5
0.03307
0.00372
100.4
0.03448
O.OO423
70.0
0.03522
0.00453
44.4
0.02551
0.00192
294.7
0.02765
0.00254
197.1
0.02963
0.00314
135.6
0.03136
0.00366
91.5
0.03264
0.00399
56.6
1100
0.00852
-
-
0.01914
0.00065
1107.7
0.02155
0.00130
504.4
0.02388
0.00193
298.8
0.02610
0.00254
191.8
0.02816
0.00308
123.5
0.03000
0.00345
73.7
1200
-
-
-
0.00789
-
-
0.01742
0.00066
1164.9
0.01995
0.00131
515.5
0.02241
0.00193
292.6
0.02482
0.00250
175.3
0.02724
0.00291
99.2
1300
-
-
*
-
-
-
0.00694
-
-
0.01580
0.00066
1208.3
0.01831
0.0013
511.1
0.02126
0.00190
269.6
0.02428
0.00236
140.7
1400
_
-
-
-
-
-
-
-
0.00492
-
-
0.01430
0.00067
1226.4
0.0173S
0.00130
479.5
0.02099
0.00181
217.3
-------
Table 9 (continued).
TOTAL QUEUE EMISSIONS, (QQJ), CRUISE COMPONENT EMISSION, (Qqc), AND
QUEUE LENGTH AS A FUNCTION OF MAJOR AND CROSS-STREET VOLUMES AND
CRUISE SPEED - SIGNALIZED INTERSECTIONS
oo
Cross-street
effective lane
T0lu»e <»eb/br>
1400
Element
V
V
1300 ; q^
1200
1100
1000
900
800
V
Queue
V
V
Queue
V
V
V
V
Queue
V
V
Queue
V
V
Queue
Major street voliaae - (usuBCd cruise speed is 40 su/br)
100
-
-
~
-
-
-
-
-
200
-
0.05177
0.00009
1901.4
0.05022
0.00046
367.9
0.04932
0.00098
173.2
0.04909
0.00162
103.9
0.04953
0.00238
70.2
0.05065
0.00323
51.0
300
0.04308
0.00032
796.5
0.04315
O.OOOO73
347.2
0.04362
0.00123
205.7
0.04450
0.00180
139.0
0.04576
0.00245
101.2
0.04739
0.00316
77.3
O.O4938
O.O0393
60.9
4OO
0.01912
0.03705
0.00051
670.4
0.03840
0.00107
314.7
0.04O01
0.00168
197.4
0.04186
0.00234
139.4
0.04395
0.00304
105.0
0.0*625
0.00379
82.3
500
-
0.01828
~
0.03322
O.OOO60
698.6
0.03525
0.00124
333.4
0.03746
0.00192
211.9
0.03981
0.00263
151.1
O.O4229
O.OO336
114.5
600
-
-
-
0.016O9
0.03030
0.00066
757.5
0.03275
0.00135
362.9
0.03530
0.00207
231.0
0.03793
0.00280
164.5
700
-
-
-
-
0.01531
0.02785
0.00070
826.6
0.03057
O.O0143
395.2
0.03334
0.00217
250.5
800
-
-
""
-
-
0.013O6
0.02567
O.OO073
899.1
0.02858
0.00148
427.4
900
-
-
-
-
-
-
-
0.02366
0.00076
971.8
1000
-
-
-
-
-
-
0.01003
1100
-
-
~
-
-
-
-
;
1200
-
-
-
-
-
-
-
;
1300
-
-
~
-
-
-
-
;
1400
-
-
_
-
-
-
-
-
-------
Table 9 (continued).
TOTAL QUEUE EMISSIONS, (QQT), CRUISE COMPONENT EMISSION, (Qqc), AND
QUEUE LENGTH AS A FUNCTION OF MAJOR AND CROSS-STREET VOLUMES AND
CRUISE SPEED - SIGNALIZED INTERSECTIONS
effective laoe
volute (veh/hr)
700
600
500
400
300
200
100
Eleoeot
V
V
Queue
Msjor street volone - (assissf li cruise speed is 40 sd/hr)
100
-
0^_ • 0.05039
V
Queue
V
V
Queue
V
V
Queue
V
V
Queue
V
V
Queue
V
V
Queue
0.00127
66.8
0.03270
0.00208
40.0
0.02107
0.00202
40.0
0.01618
0.00192
40.0
0.01300
0.00175
40.0
0.00939
0.00139
40.0
200
0.05083
0.00405
40.0
0.04177
0.00395
40.0
0.03526
0.00381
40.0
0.03011
0.00362
40.0
0.02544
0.00333
40.0
0.02044
0.00289
40.0
0.01390
0.00212
40.0
300
0.05170
0.00475
49.1
0.05430
0.00561
40.1
0.04697
0.'W536
40. J
0.04032
0.00500
40. .'
0.03377
0.00451
40.0
0.02655
0.00380
40.0
0.01762
0.00270
40.0
400
0.04871
0.00457
66.0
0.05130
0.00537
53.8
O.O5392
O.O0620
44.O
0.05049
0.00628
40.0
0.04172
0.00558
40.0
0.03231
0.00461
40.0
0.02125
0.00323
4O.O
500
0.04486
0.00412
89.8
0.04747
0.00490
71.9
0.05004
0.00569
58.0
0.05246
0.00647
46.5
0.04986
0.00661
40.0
0.03819
0.00540
40.0
0.02506
0.00375
40.0
600
0.04060
0.00356
124.2
0.04327
0.00432
96.6
0.04587
0.00509
76.3
0.04830
0.00585
60.2
0.05037
0.00657
46.6
0.04453
0.00619
40.0
0.02921
0.00427
40.0
700
0.03613
0.00292
177.2
0.03889
0.00368
132.4
0.04156
0.00444
101.4
0.04406
0.00518
78.2
0.04623
0.00589
59.4
0.04776
0.00650
43.3
0.03388
0.00483
40.0
800
0.03149
0.00223
268.6
0.03436
0.00299
187.8
0.03715
0.00375
137.9
0.03977
0.00449
103.1
0.04211
0.00519
76.5
0.04389
0.00580
54.7
0.03928
0.00542
40.0
900
0.02671
0.00152
457.6
0.02972
0.00228
283.9
0.03264
0.003O4
195.0
0.03542
0.00379
139.5
0.03796
0.00449
100.4
0.04004
0.00411
70.0
0.04117
0.00547
44.4
1000
0.02178
0.00077
1042.1
0.02494
0.00155
484.0
0.02802
0.00231
294.7
0.03098
0.00307
197.1
0.03375
0.00378
135.6
0.03616
0.00441
91.5
0.03788-
0.00481
56.6
1100
C. 00852
0.01999
0.00079
1107.7
0.02325
0.00157
504.4
0.02641
0.00233
298.8
0.02943
0.00306
191.8
0.0322O
0.00372
123.5
0.03453
0.00416
73.7
1200
-
0.00789
:
0.01829
0.00079
1164.9
0.02166
0.00158
515.5
0.02494
0.00233
292.6
0.02809
0.00301
175.3
0.03106
0.00351
99.2
1300
-
-
:
0.00694
0.01667
0.00080
1208.3
0.02023
0.00158
511.1
0.02375
0.00230
269.6
0.02738
0.00285
140.7
1400
!
-
-
-
0.004*2
0.01517
0.00081
1226.4
0.01*08
0.00156
479.5
0.02337
0.00219
217.3
-------
Table 9 (continued)
TOTAL QUEUE EMISSIONS, (Qoj), CRUISE COMPONENT EMISSION, (0™), AND
QUEUE LENGTH AS A FUNCTION OF MAJOR AND CROSS-STREET VOLUMES AND
CRUISE SPEED - SIGNALIZED INTERSECTIONS
Cro*s-*treet
effective l*n*
volu»* («eh/br)
1400
1300
1200
1 100
1000
900
BOO
Eleven t
V
V
Queue
V
V
Queue
V
V
Queue
V
Queue
V
V
Queue
V
V
Queue
V
V
Queue
H»jo
100
-
-
-
-
-
-
-
200
-
0.05189
O.OOOll
1901.4
0.05081
0.00057
367.9
0.05059
0.00120
173.2
0.05119
0.00198
103.9
0.05260
0.00291
70.2
0.05483
0.00395
51.0
300
0.04350
O.OO039
796.5
0.01410
0.00089
347.2
0.04521
0.00150
205.7
0.04683
0.00220
139.0
0.04892
0.00299
101.2
0.05147
0.00386
77.3
0.05446
0.00480
60.9
400
0.01912
0.03771
0.00062
670.4
0.03978
0.00130
314.7
0.04218
0.00205
197.4
0.04489
0.00286
139.4
0.04789
0.00372
105.0
0.05114
O.OO463
82.3
5OO
-
0.01828
0.03400
0.00074
698.6
0.03686
0.00152
333.4
0.03994
0.00235
211.9
0.04321
0.00321
151.1
0.04664
0.00411
114.5
r street voluvje - {assumed cruise speed if 4$ u/Br)
600
-
0.01609
0.03116
O.OO081
757.5
0.03450
0.00165
362.9
0.03798
0.00253
231.0
0.04156
0.00343
164.5
700
-
-
-
0.01531
-
0.02876
O.O0086
826.6
0.03242
0.00174
395.2
0.03614
0.00265
250.5
800
-
-
-
_
-
0.01306
0.02662
O.O009O
899.1
0.03049
0.00111
427.4
9OO
-
-
-
-
-
-
-
0.02464
O.OOOT2
971.8
10OO
-
-
-
-
-
-
-
0.01003
1100
_
-
;
-
-
-
-
-
-
12OO
-
-
-
-
-
-
-
!
13OO
-
-
-
-
-
-
-
;
14OO
-
-
-
-
-
-
-
-
-------
Table 9 (continued).
TOTAL QUEUE EMISSIONS, (0™), CRUISE COMPONENT EMISSION, (Qqc)» AND
QUEUE LENGTH AS A FUNCTION OF MAJOR AND CROSS-STREET VOLUMES AND
CRUISE SPEED - SIGNALIZED INTERSECTIONS
Croaa-ctreet
effective lane
voluie Ueh/hr)
700
600
500
400
300
200
100
Elenent
V
Queue
V
"PC
Queue
V
V
Ojueoe
V
V
Queue
V
V
Queue
V
V
queue
V
V
Queue
Major atreet volone - (aaa*Bjed cniae apeed ia 45 vi/hr)
100
_
-
0.05203
0.00155
66.8
0.03539
0.0025*
40.0
0.02369
0.00247
40.0
0.01866
0.00235
40.0
0.01526
0.0021*
40.0
0.01119
0.00170
40.0
200
0.05607
0.00495
40.0
0.04687
O.O0483
40.0
0.0*019
0.00*66
40.0
0.03*79
O.OO442
40.0
0.02975
0.00*07
40.0
0.02*17
0.00353
40.0
0.0166*
0.00259
40.0
300
0.05784
0.00580
49.1
0.06155
0.00686
40.1
0.05390
0.00655
40.0
3.04679
0.00611
(0.0
1.03960
U.00551
40.0
0.031*6
0.0046*
40.0
0.02111
0.00330
40.0
400
0.05462
0.00558
66.0
0.05825
0.00657
53.8
0.0619*
0.00758
44.0
0.05857
0.00768
40.0
0.0*893
0.00682
40.0
0.03827
0.00564
40.0
0.02543
0.00395
40.0
500
0.05019
0.00504
89.8
0.05380
0.00599
71.9
0.057*0
0.00695
58.0
0.06083
0.00791
46.5
0.05841
0.00808
40.0
0.04516
0.00660
40.0
0.02990
0.00458
40.0
600
0.04520
0.00434
124.2
0.04886
0.00528
96.6
0.05245
O.OO622
76.1
0.05586
0.00714
60.2
0.05886
- 0.00803
46.6
0.0525*
0.00757
40.0
0.03*7*
0.00522
40.0
700
0.03990
0.00357
117.2
O.O4364
0.00*49
132.4
0.04730
0.00542
101.4
O.O5076
0.00613
78.2
0.05384
0.00719
59.*
0.05616
0.0079*
43.3
0.0*012
O.OO59O
4O.O
800
0.03438
0.00273
268.6
0.03824
0.00366
187.8
0.04200
O. 004 58
137.9
O.O4558
0.00549
103.1
0.04882
O.OO635
76.5
0.05139
0.00709
54.7
O.O4629
0.00662
40.0
900
0.02867
0.00185
457.6
0.03267
0.00279
283.9
0.03658
O.O0172
195.0
0.0*032
O.OO463
119.5
0.0*176
0.005*9
100.*
0.0*66*
0.0062*
7O.O
0.0*824
O.OOE68
44.4
1000
0.02278
0.00094
1042.1
0.02694
O.O0189
48*. 0
0.03101
0.00283
294.7
0.03*95
0.00375
197.1
0.0386*
0.00*62
135.6
0.0*187
0.00519
91.5
0.04*09
0.00588
56.6
1100
0.00852
-
0.02101
0.00096
1107.7
0.02527
O. 00191
50*.*
0.02941
0.00285
298.8
0.01119
0.00374
191.8
0.03700
0.00454
121.5
0.01990
0.00508
71.7
1200
_
-
0.00789
0.01931
O.OO097
1164.9
0.02170
0.00191
515.5
0.02796
0.00285
292.6
0.03199
O.OO368
175.3
0.01559
0.00*28
99.2
1300
_
-
-
0.0069*
0.01771
0.00098
1201.1
O.O2227
O.O0193
511.1
0.02673
0.0028
269.6
0.01107
O. 00348
1*0.7
1400
_
-
-
-
0.00*92
0.01622
0.00098
1226.*
0.02110
0.00191
479.5
0.02620
0.00267
217.1
-------
Table 10. FREE FLOW EMISSION BATE Qf, IN GRAMS PER METER-SECOND AS A
FUNCTION OF LANE VOLUME AND VEHICLE SPEED ON ROADWAYS.
Cruise speed
(mi/hr)
15
20
25
30
35
40
45
Traffic volume for lane (vehicles per hour)
100
0.00086
0.00059
0.00045
0.00037
0.00032
0.00030
0.00029
200
0.00171
0.00119
0.00090
0.00074
0.00065
0.00060
0.00058
300
0.00257
0.00178
0.00135
0.00111
0.00097
0.00090
0.00086
400
0.00342
0.00237
0.00180
0.00148
0.00129
0.00119
0.00115
500
0.00428
0.00296
0.00225
0.00185
0.00162
0.00149
0.00144
600
0.00514
0.00356
0.00270
0.00222
0.00194
0.00179
0.00173
700
0.00599
0.00415
0.00315
0.00259
0.00226
0.00209
0.00202
800
0.00685
0.00474
0.00361
0.00296
0.00258
0.00239
0.00230
900
0.00770
0.00533
0 . 00406
0.00333
0.00291
0.00269
0.00259
1000
0.00856
0.00593
0.00451
0.00370
0.00323
0.00298
0.00288
1100
0.00942
0.00652
0.00496
0.00406
0.00355
0.00328
0.00317
1200
0.01027
0.00711
0.00541
0.00443.
0.00388
0.00358
0.00346
1300
0.01113
0.00770
0.00586
0.00480
0.00420
0.00388
0.00374
1400
0.01198
0.00830
0.00631
0.00517
0.00452
0.00418
0.00403
-------
Table 11. TOTAL QUEUE EMISSIONS, (Qgr), CRUISE COMPONENT EMISSION, (Qor), AND QUEUE LENGTH
AS A FUNCTION OF MAJOR AND CROSS-STREET VOLUMES AND CRUISE SPEED - UNSIGNALIZED
INTERSECTIONS
CroM-street
effective l««e
•oluae (nfc/hr)
1400
1300
120O
1100
.1000
900
800
Eleaeu
V
V
Queue
V
V
0
V
Quoe
V
Qnae
V
V
«uae
V
Queoe
V
V
Major ctrecc voloBt (vehicle>/haur) eraiae ipeed i* 15 n/hr
1OO
0.02945
O.OOO86
40.0
0.01604
O.O0086
4O.O
0.01056
O.OOO86
40.0
0.00777
0.00086
40.0
0.00619
O.OOO86
40.0
0.00522
O.OOO86
40.0
O.OO46O
O.OOO86
40.0
200
0.0
0.00172
40.0
0.0
0.00172
40.0
O.O
0.00172
40.O
0.05160
O.OO039
176.9
0.04640
O.O0172
40. 0
0.02456
0.00172
40.0
0.01662
0.00172
40.O
300
0.0
0.00258
40.0
0.0
0.00258
40.0
0.0
0.00258
40.0
0.0
0.00258
40.0
0.0
0.00258
40.0
0.0
0.00258
40.0
0.05237
0.00109
94.4
400
0.0
0.00344
40.0
0.0
0.00344
40.0
0.0
0.00344
40.0
0.0
0.00344
40.0
0.0
0.00344
40.0
0.0
i0.00344
40.0
0.0
0.00344
40.0
50O
0.0
0.00430
40.0
0.0
O.OO430
40.0
0.0
O.OO430
40.0
0.0
0.00430
40.0
0.0
0.00430
40.0
0.0
0.00430
40.0
0.0
0.00430
40.0
600
0.0
0.00517
40.0
0.0
0.00517
40.0
0.0
0.00517
40.0
0.0
0.00517
40.0
0.0
6.00517
40.0
0.0
0.00517
40.0
0.0
0.00517
40.0
700
0.0
0.00603
40.0
0.0
0.00603
40.0
0.0
0.00603
40.0
0.0
0.00603
40.0
0.0
O.OO603
40.0
0.0
0.00603
40.0
0.0
0.00603
40.0
800
0.0
0.00689
40.0
0.0
O.OO689
40.0
0.0
O.OO689
40.0
0.0
0.00689
40.0
0.0
0.00689
40.0
0.0
0.00689
40.0
0.0
0.00689
40.0
900
0.0
0.00775
40.0
0.0
0.00775
40.0
0.0
0.00775
40.0
0.0
0.00775
40.0
0.0
0.00775
40.0
0.0
0.00775
40.0
0.0
0.00775
40.0
1000
0.0
0.00861
40.0
0.0
0.00861
40.0
0.0
0.00861
40.0
0.0
0.00861
40.0
0.0
0.00861
40.0
0.0
0.00861
40.0
0.0
0.00861
40.0
1100
0.0
0.00947
40.0
0.0
0.00947
40.0
0.0
0.00947
40.0
0.0
0.00947
40.0
0.0
0.00947
40.0
0.0
0.00947
40.0
0.0
0.00*47
40.0
1200
0.0
0.01033
40.0
0.0
0.01033
40.0
0.0
O.01O33
40.0
0.0
0.01033
40.0
0.0
0.01033
40.0
0.0
0.01033
40.0
0.0
0.1033
40.0
1300
0.0
0.01119
40.0
0.0
0.0111*
40.0
0.0
0.01119
40.0
0.0
0.01119
40.0
0.0
0.01119
40 JO
0.0
0.01119
40.0
0.0
0.01119
40.0
1400
0.0
0.012O5
40.0
O.O
0.01205
4O.O
0.0
0.012O5
40.0
0.0
0.01205
40.0
D.O
0.01205
40.0
0.0
0.01205
40.0
0.0
0.01205
40.0
-------
Table 11 (continued). TOTAL QUEUE EMISSIONS, (QQT), CRUISE COMPONENT EMISSION, (QQC), AND
QUEUE LENGTH AS A FUNCTION OF MAJOR AND CROSS-STREET VOLUMES AND
CRUISE SPEED - UNSIGNALIZED INTERSECTIONS
Croftl-Btreet
effective lm*
voluse (veh/hr)
700
600
500
400
300
200
100
Element
V
V
Queue
V
V
Queue
V
V
Queue
V
V
Queue
V
V
Queue
V
V
Queue
V
V
Queue
tUjor •erect voluM (vefciclei/hour) cruifle Bpe«d im 15 ai/hr
100
0.00419
0.00086
40.0
0.00391
0.00086
40.0
0.00372
0.00086
40.0
0.00358
0.00086
40.0
0.00348
0.00086
40.0
0.00341
0.00086
40.0
0.00336
0.00086
40.0
200
0.01276
0.00172
40.0
0.01059
0.00172
40.0
0.00928
0.00172
40.0
0.00844
0.00172
40.0
0.00787
0.00172
40.0
0.00748
0.00172
40.0
0.00720
0.00172
40.0
300
0.0*331
0.00258
40.0
0.02647
0.00258
40.0
0.01959
0.00258
40.0
0.01605
0.00258
40.0
0.01399
0.00258
40.0
0.01269
0.00258
40.0
0.01184
0.00258
40.0
400
0.0
O.O0344
40.0
0.05351
0.00127
108.3
0.05036
0.00344
40.0
0.03164
0.00344
40.0
0.02405
0.00344
40.0
0.02014
0.00344
40.0
0.01785
0.00344
40.0
5OO
0.0
0.00430
40.0
0.0
0.00430
40.0
0.0
0.00430
40.0
0.05622
0.00252
68.4
0.04697
0.00430
40.0
0.03293
0.00430
40.0
0.02659
0.00430
40.0
600
0.0
0.00517
40.0
0.0
0.00517
40.0
0.0
0.00517
40.0
0.0
0.00517
40.0
0.05494
0.00142
145.1
0.06221
0.00494
41.8
0.04208
0.00517
40.0
700
0.0
800
0.0
0.00603 0.00689
900
0.0
0.00775
40.0 40.0 40.0
o.o ; o.o o.o
0.00603
40.0
0.0
0.00603
40.0
0.0
0.00603
40.0
0.0
0.00603
40.0
0.05369
0.00064
379.3
0.06211
0.00446
54.0
0.00689 . 0.00775
40.0
0.0
0.00689
40.0
0.0
0.00689
40.0
0.0
0.00775
40.0
0.0
0.00775
40 . 0 I 40 . 0
1
0.0
0.00689
40.0
0.0
0.00689
40.0
0.05278
0.00016
1729.4
0.0
0.00775
40.0
0.0
0.00775
40.0
0.0
0.00775
40.0
1000 ] 1100
0.0
0.0
0.00861 j 0.00947
40.0
0.0
0.00861
40.0
0.0
0.00861
40.0
0.0
0.00861
40.0
0.0
0.00861
40.0
0.0
0.00861
40.0
0.0
0.00(61
40.0
40.0
0.0
0.00947
40.0
0.0
0.00947
40.0
0.0
0. 00947
40.0
0.0
0.00947
40.0
0.0
0.00947
40.0
0.0
0.00447
40.0
1200
0.0
0.01033
40.0
0.0
0.01033
40.0
0.0
0.01033
40.0
0.0
0.01033
40.0
0.0
0.01033
40.0
0.0
0.01033
40.0
0.0
0.01033
40.0
13OO
0.0
0.01119
40.0
0.0
0.01119
40.0
0.0
0.01119
40.0
0.0
0.01119
40.0
0.0
0.01119
40.0
0.0
0. 01119
40.0
0.0
0.01119
40.0
1400
0.0
0.01205
40.0
0.0
0.01205
40.0
0.0
0.01205
40.0
0.0
0.0120S
40.0
0.0
0.01205
40.0
0.0
0.01205
40.0
0.0
0.01205
40.0
-------
Table 11 (continued).
TOTAL QUEUE EMISSIONS, (QgT), CRUISE COMPONENT EMISSION, (Qqc), AND
QUEUE LENGTH AS A FUNCTION OF MAJOR AND CROSS-STREET VOLUMES AND
CRUISE SPEED - UNSIGNALIZED INTERSECTIONS
Cross-atreet
effective lane
volu»e <»«*/hr)
1400
1300
1200
1100
1000
900
800
EleKot
V
V
Queue
V
V
Queue
V
V
Queue
V
"QC
Queue
V
Queue
V
"QC
Queue
V
Queue
Major street voloae (vehiclea/bour) cruiae apeed ia 20 ai/hr
- 100
0.03066
0.00106
40.0
0.01725
0.00106
40.0
0.01177
0.00106
40.0
0.00898
0.00106
40.0
0.00739
0.00106
40.0
0.00643
0.00106
40.0
0.00581
0.00106
40.0
200
0.0
0.00212
40.0
0.0
0.00212
40.0
0.0
0.00212
40.0
0.05215
0.00048
176.9
0.04882
0.00212
40.0
0.02698
0.00212
40.0
0.01904
0.00212
40.0
300
0.0
0.00318
40.0
0.0
0.00318
40.0
0.0
0.00318
40.0
0.0
0.00318
40.0
0.0
0.00318
40.0
0.0
0.00318
40.0
0.05391
0.00135
94.4
400
0.0
0.00424
40.0
0.0
0.00424
40.0
0.0
0,00424
40.0
0.0
0.00424
40.0
0.0
0.00424
40.0
0.0
0.00424
40.0
0.0
0.00424
40.0
500
0.0
0.00530
40.0
0.0
0.00530
40.0
0.0
0.00530
40.0
0.0
0.00530
40.0
0.0
0.00530
40.0
0.0
0.00530
40.0
0.0
0.00530
40.0
600
0.0
0.00636
40.0
0.0
0.00636
40.0
0.0
0.00636
40.0
0.0
0.00636
40.0
0.0
0.00636
40.0
0.0
0.00636
40.0
0.0
0.00636
40.0
700
0.0
0.00742
40.0
0.0
0.00742
40.0
0.0
0.00742
40.0
0.0
0.00742
40.0
0.0
0.00742
40.0
0.0
0.00742
40.0
0.0
0.00742
40.0
800
0.0
0.00848
40.0
0.0
0.00848
40.0
0.0
0.00848
40.0
0.0
0.00848
40.0
0.0
0.00848
40.0
0.0
0.00848
40.0
0.0
0.00848
40.0
900
0.0
0.00954
40.0
0.0
0.00954
40.0
0.0
0.00954
40.0
0.0
0.00954
40.0
0.0
0.00954
40.0
0.0
0.00954
40.0
0.0
0.00954
40.0
1000
0.0
0.01060
40.0
0.0
0.01060
40.0
0.0
0.01060
40.0
0.0
0.01060
40.0
0.0
0.01060
40.0
0.0
0.01060
40.0
0.0
0.01060
40.0
,1100
o.o
0.01166
40.0
0.0
0.01166
40.0
0.0
0.01166
40.0
0.0
0.01166
40.0
0.0
0.01166
40.0
0.0
0.01166
40.0
0.0
0.01166
40.0
1200
0.0
0.01272
40.0
0.0
0.01272
40.0
0.0
0.01272
40.0
0.0
0.01272
40.0
0.0
0.01272
40.0
0.0
0.01272
40.0
0.0
0.01272
40.0
1300
0.0
0.01377
40.0
0.0
0.01377
40.0
0.0
0.01377
40.0
0.0
0.01377
40.0
0.0
0.01377
40.0
0.0
0.01377
40.0
0.0
0.01377
40.0
1400
0.0
0.01483
40.0
0.0
0.01483
40.0
0.0
0.01483
40.0
0.0
0.01483
40.0
0.0
0.01483
40.0
0.0
0.01483
40.0
0.0
0.01483
40.0
-------
Table 11 (continued).
TOTAL QUEUE EMISSIONS, (QqT), CRUISE COMPONENT EMISSION, (Q AND
QUEUE LENGTH AS A FUNCTION OF MAJOR AND CROSS-STREET VOLUMES AND
CRUISE SPEED - UNSIGNALIZED INTERSECTIONS
Cro*.«-»treet
effective l«e
voli^ (vch/br)
70O
6OO
5OO
400
MO
TOO
100
rii» iir
V
V
Queue
V
V
q»*u«
V
V
Quo*
V
V
Queue
V
V
Q»a»
V
V
0— ™
V
V
Q-~
Major «trect vol«e (vehielei/hour) cruice •peed im 20 oi/hr
100
0.00 MO
0.00106
40.0
0.00512
0.00106
40.0
0.00493
0.0010*
40.0
0.00479
0.00106
40.0
0.004*9
0.00106
40.0
0.00462
0.00106
40.0
0.00436
0.00106
40.0
200
0.01517
0.00212
40.0
0.01501
0.00212
40.0
0.01170
0.00212
40.0
0.01083
0.00212
40.0
0.01029
0.00212
40.0
0.00990
0.00212
40.0
0.00962
0.00212
40.0
300
0.04693
0.00318
40.0
0.03010
0.00318
40.0
0.02322
0.00318
40.0
0.01968
0.00318
40.0
0.01761
0.00318
40.0
0.01632
0.00318
40.0
0.01547
0.00318
40.0
400
0.0
0 . 00424
40.0
0.05530
0.00157
108.3
0.05520
0.00424
40.0
0.03647
0.00424
40.0
0.02889
0.00424
40.0
0.02497
0.00424
40.0
0.02269
0.00424
40.0
5OO
0.0
0.00530
40.0
0.0
0.00530
40.0
0.0
0.00530
40.0
0.05975
0.00310
68.4
0.03301
0.00530
40.0
0.03898
0.00530
40.0
0.03264
0.00530
40.0
600
0.0
0.00636
40.0
0.0
0.00636
40.0
0.0
0.00636
40.0
0.0
0.00636
40.0
0.056*4
0.00175
145.1
0.06913
0.00608
41.8
0.04934
O.OO636
41.8
700
0.0
0.00742
40.0
0.0
0.00742
4O.O
0.0
0.00742
40.0
0.0
0.00742
40.0
0.0
0.00742
40.0
0.05459
0.00078
379.3
0.06838
0.00549
800
0.0
0.00848
40.0
0.0
0.00848
40.0
0.0
0.00848
40.0
0.0
0.00848
40.0
0.0
0.00848
40.0
0.0
0.00848
40.0
0.05301
0.00020
1729.4
900
0.0
0.00954
40.0
0.0
0.00954
40.0
0.0
0.00954
40.0
0.0
0.00934
40.0
0.0
0.00934
40.0
0.0
0.00954
40.0
0.0
0.00934
40.0
1000
0.0
0.01060
40.0
0.0
0.01060
40.0
0.0
0.01060
40.0
0.0
0.01060
40.0
0.0
0.01060
40.0
0.0
0.01060
40.0
0.0
0.01060
40.0
1100
0.0
0.01166
40.0
0.0
0.01166
40.0
0.0
0.01166
40.0
0.0
0.01166
40.0
0.0
0.01166
40.0
0.0
0.01166
40.0
0.0
0.0116*
40.0
1200 1300 1400
0.0 0.0 0.0
0.01272 0.01377 0.01483
40.0 40.0 40.0
0.0 0.0 0.0
0.01272 0.01377 0.01483
40.0 40.0 40.0
0.0 0.0 0.0
0.01272 0.01377 0.014(3
40.0 40.0 40.0
0.0 0.0 0.0
0.01272 0.01377 0.01483
40.0 40.0 40.0
0.0 0.0 0.0
0.01272 0.01377 0.01483
40.0 40.0 40.0
0.0 0.0 0.0
0.01272 0.01377 0.01*8]
40.0 40.0 40.0
0.0 0.0 0.0
0.01272 0.01377 0.0148]
40.0 40.0 40.0
-------
Table 11 (continued).
TOTAL QUEUE EMISSIONS, (QQT), CRUISE COMPONENT EMISSION, (Qqc), AND
QUEUE LENGTH AS A FUNCTION OF MAJOR AND CROSS-STREET VOLUMES AND
CRUISE SPEED - UNSIGNAL1ZED INTERSECTIONS
Croaa-atreet
effective lane
volwne (veh/hr)
1400
1300
1200
1100
10OO
900
800
Eleamt
V
V
Queue
V
V
Queue
V
V
Queue
V
V
Queue
V
V
Queue
V
Queue
V
V
Queue
Major atreet voluve (vefciclea/hour) eruiae apeed la 25 ai/hr
100
0.03205
0.00126
40.0
0.01864
0.00126
40.0
0.01316
0.00126
40.0
0.01037
0.00126
40.0
0.00879
0.00126
40.0
0.00782
0.00126
40.0
0.00720
0.00126
40.0
200
0.0
0.00252
40.0
0.0
0.00252
40.0
0.0
0.00252
40.0
0.05278
0.00057
176.9
0.05160
0.00252
40.0
0.02976
0.00252
40.0
0.02182
0.00252
40.0
300
0.0
0.00378
40.0
0.0
0.00378
40.0
0.0
0.00378
40.0
0.0
0.00378
40.0
0.0
0.00378
40.0
0.0
0.00378
40.0
0.05568
0.00160
94.4
400
0.0
0.00504
40.0
0.0
0.00504
40.0
0.0
0.00504
40.0
0.0
0.00504
40.0
0.0
0.00504
40.0
0.0
0.00504
40.0
0.0
0.00504
40.0
500
0.0
0.00630
40.0
0.0
0.00630
40.0
0.0
0.00630
40.0
0.0
0.00630
40.0
0.0
0.00630
40.0
0.0
0.00630
40.0
0.0
0.00630
40.0
600
0.0
700
0.0
0.00756 ; 0.00881
40.0 ! 40.0
0.0 ; 0.0
0.00756 ; 0.00881
40.0 40.0
0.0
0.00756
40.0
0.0
0.00756
0.0
0.00881
40.0
0.0
0.00881
40.0 j 40.0
0.0
0.00756
40.0
0.0
0.00756
40.0
0.0
0.0075*
40.0
0.0
0.00881
40.0
0.0
0.00881
40.0
0.0
0.00881
40.0
800
o'.o
0.01007
40.0
0.0
0.01007
40.0
0.0
0.01007
40.0
0.0
0.01007
40.0
0.0
0.01007
40.0
0.0
0.01007
40.0
0.0
0.01007
40.0
900
0.0
0.01133
40.0
0.0
0.01133
40.0
0.0
0.01133
40.0
0.0
0.01133
40.0
0.0
0.01133
40.0
0.0
0.01133
40.0
0.0
0.01133
40.0
1000
0.0
1100
0.0
0.01259 0.01385
40.0
40.0
0.0 I 0.0
0.01259
40.0
0.0
0.01259
40.0
0.0
0.01259
40.0
0.0
0.01259
40.0
0.0
0.01259
40.0
0.0
0.01259
40.0
0.01385
40.0
0.0
0.01385
40.0
0.0
0.01385
40.0
0.0
0.01385
40.0
0.0
0.01385
40.0
0.0
0.01385
40.0
1200
0.0
0.01511
40.0
0.0
0.01511
40.0
0.0
0.01511
40.0
0.0
0.01511
40.0
0.0
0.01511
40.0
0.0
0.0511
40.0
0.0
0.01511
40.0
1300
0.0
0.01637
40.0
0.0
0.01637
40.0
0.0
0.01637
40.0
0.0
0.01637
40.0
0.0
0.01637
40.0
0.0
0.01637
40.0
0.0
0.01637
40.0
1400
0.0
0.01763
40.0
0.0
0.01763
40.0
0.0
0.01763
40.0
0.0
0.01763
40.0
0.0
O.O1763
40.0
0.0
0.01763
40.0
0.0
0.01763
40.0
-------
Table 11 (continued).
TOTAL QUEUE EMISSIONS, (QQ-jO, CRUISE COMPONENT EMISSION, (Qg(0, AND
QUEUE LENGTH AS A FUNCTION OF MAJOR AND CROSS-STREET VOLUMES AND
CRUISE SPEED - UNSIGNALIZED INTERSECTIONS
00
Crosc-vtrect
effective lane
•oline (»eh/lir)
700
600
500
400
300
200
100
Element
V
Queue
V
V
Queue
V
V
Queue
V
V
Queue
V
V
Queue
V
V
Queue
V
V
Queue
Major street voluae (vehicles/tour) crniae Bpecd i» 25 «i/br
100
0.00479
0.00126
40.0
200
0.01796
0.00252
40.0
0.00651 0.01580
300
0.05111
0.00378
40.0
0.03427
0.00126 0.00252 I O.O0378
40.0
0.0632
0.00126
40.0
0.00618
0.00126
40.0
0.00608
0.00126
40.0
0.00601
0.00126
40.0
0.00596
0.00126
40.0
40.0 , 40.0
0.01448
0.00252
40.0
0.01364
0.02740
0.00378
40.0
0.02385
0.00252 \ 0.00378
40.0 ; 40.0
\
0.01307 j 0.02179
0.00252
40.0
0.01268
0.00252
40.0
0.01241
0.00252
40.0
0.00378
40.0
0.02050
0.00378
40.0
0.01964
0.00378
40.0
400
0.0
0.00504 •
40.0
0.05736
0.00186
108.3
0.06076
0.00504
4O.O
0.04204
0.005O4
40.0
0.03445
0.00504
40.0
0.03054
0.00504
40.0
0.02825
0.00504
40.0
500
0.0
0.00630
40.0
0.0
0.00630
40.0
0.0
0.00630
40.0
0.06387
0.00368
68.4
0.05997
0.0063O
40.0
0.04593
0.00630
40.0
0.03960
0.00630
40.0
600
0.0
0.00756
40.0
0.0
0.00756
40.0
0.0
0.00756
40.0
0.0
0.00756
40.0
0.05924
0.00208
145.1
0.07713
0.00723
41.8
0.05769
0.00756
40.0
700
0.0
0.00881
40.0
0.0
0.00881
40.0
0.0
0.00881
40.0
0.0
0.00881
40.0
0.0
0.00881
40.0
0.05561
0.00093
379.3
0.07559
0.00653
54.0
800
0.0
0.01007
40.0
0.0
0.01007
40.0
0.0
0.01007
40.0
0.0
0.01007
40.0
0.0
0.01007
40.0
0.0
0.01007
40.0
0.05326
0.00023
1729.4
900
0.0
1000
0.0
0.01133 0.01259
40.0
0.0
0.01133
40.0
0.0
0.01133
40.0
0.0
0.01133
40.0
0.0
0.01239
1100
0.0
0.01385
40.0
0.0
0.01385
40.0 j 4O.O
0.0
0.01259
40.0
0.0
0.01259
40.0 i 40.0
0.0
0.01133
40.0
0.0
0.01133
40.0
0.0
0.01133
40.0
0.0
0.01259
40.0
0.0
0.01259
40.0
0.0
0.01259
40.0
0.0
0.01385
40.0
0.0
0.01385
40.0
0.0
0.01385
40.0
0.0
0.01385
40.0
0.0
0.01385
40.0
1200
0.0
0.01511
40.0
0.0
0.01511
40.0
0.0
0.01511
40.0
0.0
0.01511
40.0
0.0
0.01511
40.0
0.0
0.01511
40.0
0.0
0.01511
40.0
1300
0.0
0.01637
40.0
0.0
0.01637
40.0
0.0
0.01637
40.0
0.0
0.01637
40.0
0.0
0.01637
40.0
0.0
0.01637
40.0
0.0
0.01637
40.0
1400
0.0
0.0176}
40.0
0.0
0.01763
40.0
0.0
0.01763
40.0
0.0
0.017*3
40.0
0.0
0.01763
40.0
0.0
O.O1763
40.0
0.0
0.01763
40.0
-------
Table 11 (continued).
TOTAL QUEUE EMISSIONS, (QQT), CRUISE COMPONENT EMISSION, (QQ/J), AND
QUEUE LENGTH AS A FUNCTION OF MAJOR AND CROSS-STREET VOLUMES AND
CRUISE SPEED - UNSIGNALIZED INTERSECTIONS
Cross-street
effective lane
voluae (veh/hr>
1400
1300
1200
Ele«.t
"or
Queue
V
V
Queue
V
«<*
Queue
1100 ^
V
Queue
1000 0^.
900
800
V
Queue
V
V
Queue
•v
-------
Table 11 (continued).
TOTAL QUEUE EMISSIONS, (Qoj), CRUISE COMPONENT EMISSION, (QqC), AND
QUEUE LENGTH AS A FUNCTION OF MAJOR AND CROSS-STREET VOLUMES AND
CRUISE SPEED - UNSIGNALIZED INTERSECTIONS
Cro«»-atre«t
effective line
voliMC (veh/hr)
700
600
500
400
300
200
100
Element
V
V
Queue
' V
: V
Queue
V
V
Queue
V
V
Queue
V
V
Queue
V
V
Queue
V
V
Queue
100
0.00843
0.00149
40.0
C. 00815
0.00149
40.0
0.00796
0.00149
40.0
0.00782
0.00149
40.0
0.00772
0.00149
40.0
0.00765
0.00149
40.0
0.00759
0.00149
40.0
ZOO
0.02123
0.00297
40.0
0.01907
0.00297
40.0
0.01776
0.00297
40.0
0.01691
0.00297
40.0
0.01635
0.00297
40.0
0.01596
0.00297
40.0
0.01568
0.00297
40.0
300
0.05602
O.OO446
40.0
0.03919
0.00496
40.0
0.03231
0.00446
40.0
0.02876
0.00444
40.0
0.02670
0.00446
40.0
0.02541
0.00446
40.0
0.02456
0.00446
40.0
400
0.0
0.00595
40.0
0.05977
0.00220
108.3
0.06732
0.00595
40.0
0.04859
0.00595
40.0
0.04101
0.00595
40.0
0.03709
0.00595
40.0
0.0.1481
0.00595
40.0
500
0.0
0.00743
40.0
0.0
0.00743
40.0
0.0
0.00743
40.0
0.06861
0.00435
68.4
0.06816
0.00743
40.0
0.05412
0.00743
40.0
0.04778
0.00743
40.0
600
0.0
0.00892
40.0
0.0
0.00892
40.0
0.0
0.00892
40.0
0.0
0.00892
40.0
0.06195
0.00246
145.1
0.08653
0.00853
41. <
0.06751
0.00692
40.0
700
0.0
0.01041
40.0
0.0
0.01041
40.0
0.0
0.01041
40.0
0.0
0.01041
40.0
0.0
0.01041
40.0
0.05682
0.00110
379.3
0.08408
0.00771
54.0
800
0.0
0.01189
40.0
0.0
0.01189
40.0
0.0
0.01189
40.0
0.0
0.01189
40.0
0.0
0.01189
40.0
0.0
0.01189
40.0
0.05357
0.00028
1729.4
900
3.0
0.01338
40.0
0.0
0.01338
40.0
0.0
0.01338
40.0
0.0
0.01338
40.0
0.0
0.01338
40.0
0.0
0.01338
40.0
0.0
0.01338
40.0
•i/hr
1000
0.0
0.01487
40.0
0.0
0.01487
40.0
0.0
0.01487
40.0
0.0
0.01487
40.0
0.0
0.01487
40.0
0.0
0.01487
40.0
0.0
0.01487
40.0
1100
0.0
0.01635
40.0
0.0
0.01635
40.0
0.0
0.01(35
40.0
0.0
0.01635
40.0
0.0
0.01(35
40.0
0.0
0.01(35
40.0
0.0
0.01*35
40.0
L2OO
0.0
0.01784
40.0
0.0
0.01784
40. 0
0.0
0.01784
40.0
0.0
0.01784
40.0
0.0
0.01784
40.0
0.0
0.01784
40.0
0.0
0.01784
40.0
1100
i
0.0
0.01933
40.0
0.0
0.01933
40.0
0.0
0.01913
40.0
0.0
0.01933
40.0
0.0
0.01933
40.0
0.0
0.01933
40.0
0.0
0.01933
40.0
1400
0.0
0.02082
40.0
0.0
0.02082
40.0
0.0
0.02082
40.0
0.0
0.02082
40.0
0.0
0.02O82
40.0
0.0
0.02082
40.0
0.0
0.02082
40.0
-------
Table 11 (continued).
TOTAL QUEUE EMISSIONS, (QqT), CRUISE COMPONENT EMISSION, (QQC), AND
QUEUE LENGTH AS A FUNCTION OF MAJOR AND CROSS-STREET VOLUMES AND
CRUISE SPEED - UNSIGNALIZED INTERSECTIONS
effective Ia=*
*oloie (nh/hr)
1400
1300
12OO
1100
1000
90O
800
Eleueat
V
V
Queue
V
Queue
V
V
Queue
V
V
Queue
V
Queue
V
Queue
V
Onue
Major Btreet voluae (vebiclea/nour) cruise Bpeed if 35 «i/hr
100
0.03564
0.00177
40.0
2OO
0.0
O.O0354
40.0
0.02223 0.0
0.00177 0.00354
40.0 40.0
0.01674
0.00177
40.0
0.01396
O.O0177
40.0
0.01127
0.00177
4O.O
0.01140
0.00177
40.0
0.01079
0.00177
40.0
0.0
O.O035*
40.0
0.05440
0.00080
176.9
0. 05*77
0.00354
40.0
0.03693
0.00354
40.0
0.02899
0.0035*
40.0
300
0.0
0.00531
40.0
0.0
0.00531
40.0
0.0
0.00531
40.0
0.0
0.00531
40.0
0.0
0.00531
40.0
0.0
0.00531
40.0
0.06023
0. 00225
94.4
4OO
0.0
0.00708
40.0
0.0
0.00708
40.0
0.0
0.00708
40.0
0.0
0.007O8
40.0
0.0
0.007O8
40.0
0.0
0.007O8
40.0
0.0
0.00708
40.0
500
0.0
0.00885
40.0
0.0
0.00885
40.0
0.0
0.00885
40.0
0.0
0.00885
40.0
0.0
0.00885
40.0
0.0
O.OO885
40.0
0.0
0.00885
40.0
600
0.0
0.01062
40.0
0.0
0.01062
700
0.0
0.01239
40.0
0.0
0.01239
40.0 j 40.0
0.0
0.01062
40.0
0.0
0.01062
40.0
0.0
0.01062
40.0
0.0
0.01062
40.0
0.0
0.01062
40.0
0.0
0.01239
40.0
0.0
0.01239
40.0
0.0
0.01239
40.0
0.0
0.01239
40.0
0.0
0.01239
40.0
800
0.0
0.01415
40.0
0.0
0.01415
40.0
0.0
0.01*15
40.0
0.0
0.01*15
40.0
0.0
0.01*15
40.0
0.0
0.01415
40.0
0.0
0.01415
40.0
900
0.0
O.C1592
40.0
1000
0.0
0.01769
40.0
0.0 0.0
0.01592 0.01769
40.0
0.0
0.01592
40.0
0.0
0.01592
40.0
0.0
0.01592
40.0
0.0
0.01592
40.0
0.0
0.01592
40.0
0.0
0.01769
40.0
0.0
0.01769
40.0
0.0
0.01769
40.0
0.0
0.01769
40.0
0.0
0.01769
40.0 40.0
1100
0.0
0.01946
40.0
0.0
0.01946
40.0
0.0
0.019*6
40.0
0.0
0.019*6
40.0
0.0
0.01946
40.0
0.0
0.01946
40.0
0.0
0.019*6
40.0
1200
0.0
0.02123
40.0
0.0
0.02123
40.0
0.0
0.02123
40.0
0.0
0.02123
40.0
0.0
0.02123
40.0
0.0
0.02123
40.0
0.0
0.02123
40.0
1300
0.0
0.02300
40.0
0.0
0.02300
40.0
O.O
0.02300
40.0
0.0
0.02300
40.0
0.0
0.02300
40.0
0.0
0.02300
40.0
0.0
0.02300
40.0
1*00
0.0
0.02*77
40.0
0.0
O.O2477
40.0
O.O
0. 02477
4O.O
O.O
0.02*77
4O.O
0.0
0.02*77
4O.O
0.0
0.02*77
4O.O
O.O
0.02*77
40.0
-------
Table 11 (continued).
TOTAL QUEUE EMISSIONS, (QqT), CRUISE COMPONENT EMISSION, (QqC), AND
QUEUE LENGTH AS A FUNCTION OF MAJOR AND CROSS-STREET VOLUMES AND
CRUISE SPEED - UNSIGNALIZED INTERSECTIONS
NJ
Cro«i-Btreet
effective leoe
voluoe (veb/hr)
~00
400
500
400
300
200
100
Element
100
Q_ 0.01036
200
0.02513
ol. 0.00177 0.00354
Queue 40.0 i 40.0
1
Q 0.01010 ! 0.02297
Q : 0.00177
Queue
V
V
Queue
V
V
Queue
V
V
Queue
V
V
Queue
V
V
Q»«e
40.0
0.00990
0.00177
40.0
0.009'7
0.00177
0.00354
40.0
0.02165
0.00354
40.0
0.02081
0.00354
40.0 J 40.0
0.00967
0.02024
0.00177 0.00354
40.0
0.00959
0.00177
40.0
0.00954
0.00177
40.0
40.0
0.01985
0.00354
40.0
0.01958
0.00354
40.0
>Ujor street voluM (vehiclci/hour) eruiee speed i» 35 ai/hr
300
0.06187
0.00531
40.0
0.04503
400
0.0
0.00708
40.0
0.06265
0.00531 0.00261
40.0
0.03815
108.3
0.07511
0.00531 0.00708
40.0 40.0
0.03461
0.05638
0.00531 0.00708
40.0
40.0
0.03254 I 0.04880
0.00531
40.0
0.03125
0.00531
40.0
0.03040
0.00531
40.0
0.00708
40.0
0.4488
0.00708
40.0
0.04260
0.00708
40.0
500
0.0
600
0.0
700
0.0
0.00885 0.01062 ) 0.01239
800
0.0
900
0.0
0.01415 0.01512
40.0 40.0 ; 40.0 40.0 ; 40.0
0.0 | 0.0 i 0.0 0.0 ' 0.0
0.00885 i 0.01062 | 0.01239| 0.01415 1 0.01592
40.0
0.0
0.00885
40.0
0.07431
0.00517
68.4
0.07790
0.00885
40.0
0.6386
0.00885
40.0
0.05752
0.00885
40.0
40.0
0.0
0.01062
40.0
0.0
0.01062
40.0
0.06518
0.00293
145.1
0.09771
0.01015
40.0
0.007920
0.01062
40.0
40.0
0.0
0.01239
40.0
0.0
40.0 < 40-.0
0.0
0.01415
0.0
0.01592
40.0 i 40.0
I
0.0 0.0
0.01239 0.01415
0.01592
40.0 40.0 | 40.0
0.0 { 0.0
0.0
0. 01239 j 0.01415 0.01592
40.0
0.05826
0.00131
379.3
0.09418
O.OO917
54.0
40.0
0.0
0.01415
40.0
0.0
10CO 1 1100
o.o 1 o.o
0.01769 ! 0.01946
40.0
40.0
o.o • o.o
0.01769 ' 0.01946
40.0 40.0
0.0
0.01769
40.0
0.0
0.01946-
40.0
0.0 0.0
I
0.01769 j 0.01946
40.0 i 40.0
0.0 , 0.0
0.01769 i 0.01946
40.0
40.0
0.0 1 0.0
0.01592 | 0.01769
40.0 40.0
0.05393
0.00033
1729.4
0.0
0.01592
40.0
1200
0.0
0.02123
40.0
0.0
0.02123
40.0
0.0
0.02123
40.0
0.0
0.02123
40.0
0.0
0.02123
40.0
0.0
0.01946 0.02123
40.0 40.0
0.0
0.01769
40.0
0.0
0.01946
40.0
40.0
0.0
0.02123
40.0
1300
0.0
0.02300
40.0
0.0
0.02300
40.0
0.0
0.02300
40.0
0.0
0.02300
40.0
0.0
0.02300
40.0
0.0
0.02300
40.0
0.0
0.02300
40.0
1400
0.0
0.02477
40.0
0.0
0.02477
40.0
0.0
0.02477
40.0
0.0
0.02477
40.0
0.0
0.02477
40.0
0.0
0.02477
40.0
0.0
0.02477
40.0
-------
Table 11 (continued).
TOTAL QUEUE EMISSIONS, (QQT), CRUISE COMPONENT EMISSION, (Qqc), AND
QUEUE LENGTH AS A FUNCTION OF MAJOR AND CROSS-STREET VOLUMES AND
CRUISE SPEED - UNSIGNALIZED INTERSECTIONS
Cro»s~*treet
effective Ituw
voluae (veh/hr)
Element
ItOO n
V
Queue
1300 Q
V
1200
1100
1000
900
800
Queue
V
V
V
V
Queue
V
V
Queue
V
V
Queue
V
V
Queue
tejor street volisae (vehicles/hour) cruise speed is 40 ei/hr
100
0.03796
0.00213
40.0
0.02455
0.00213
40.0
0.01907
0.00213
40.0
0.01628
0.00213
40.0
0.01469
0.00213
40.0
0.01373
0.00213
40.0
0.01311
0.00213
40.0
200
0.0
0.00427
40.0
0.0
0.00427
40.0
0.0
0.00427
40.0
0.05545
0.00096.
176.9
0.06342
0.00427
40.0
0.04157
0.00427
40.0
0.03363
0.00427
40.0
300
0.0
0.0640
40.0
0.0
0.00640
40.0
0.0
0.00640
40.0
0.0
0.00640
40.0
0.0
0.00640
40.0
0.0
400
0.0
0.00854
40.0
0.0
0.00854
40.0
0.0
0.00854
40.0
0.0
0.00854
40.0
0.0
0.00854
40.0
0.0
0.00640 0.00854
40.0
0.06318
0.00271
94.4
40.0
0.0
0.00854
40.0
500
0.0
0.0106?
40.0
0.0
0.01067
40.0
0.0
0.01067
40.0
0.0
0.01067
40.0
0.0
0.01067
40.0
0.0
0.01067
40.0
o.o
0.01067
40.0
600
0.0
0.01280
40.0
0.0
0.01780
40.0
0.0
0.01280
40.0
0.0
0.01280
40.0
0.0
0.01280
40.0
0.0
0.01280
40.0
0.0
0.01280
40.0
700
0.0
0.01494
40.0
0.0
0.01494
40.0
0.0
0.01494
40.0
0.0
0.01494
40.0
0.0
0.01494
40.0
0.0
0.01494
40.0
0.0
0.01494
40.0
800
0.0
0.01707
40.0
0.0
0.01707
40.0
0.0
0.01707
40.0
0.0
0.01707
40.0
0.0
0.01707
40.0
0.0
0.01707
40.0
0.0
. 0.01707
40.0
900 "
0.0
0.01921
40.0
0.0
0.01921
40.0
0.0
0.01921
40.0
0.0
0.01921
40.0
0.0
0.01921
40.0
0.0
0.01921
40.0
0.0
0.01921
40.0
1000
0.0
0.02134
40.0
0.0
0.02134
40.0
0.0
0.02134
40.0
0.0
0.2134
40.0
0.0
0.02134
40.0
0.0
0.02134
40.0
0.0
0.02134
40.0
1100
0.0
0.02347
40.0
0.0
0.02347
40.0
0.0
0.02347
40.0
0.0
0.02347
40.0
0.0
0.023*7
40.0
0.0
0.02347
40.0
0.0
0.02347
40.0
1200
1300
0.0 0.0
0.02561
0.02774
40.0 40.0
0.0 . 0.0
0.02561 i 0.02774
40.0 i 40.0
0.0 0.0
0.02561
0.02774
40.0 ! 40.0
1
0.0 0.0
0.02561 j 0.02774
40.0 ' 40.0
0.0 ' 0.0
!
0.02561 j 0.02774
40.0 : 40.0
0.0
0.02561
40.0
0.0
0.02561
40.0
0.0
0.02774
40.0
0.0
0.02774
40.0
1400
0.0
0.02988
40.0
0.0
0.02988
40.0
0.0
0.02988
60.0
0.0
0.02988
40.0
0.0
0.02988
40.0
0.0
0.02988
40.0
0.0
0.02988
40.0
-------
Table 11 (continued). TOTAL QUEUE EMISSIONS, (QQT), CRUISE COMPONENT EMISSION, (QQC), AND
QUEUE LENGTH AS A FUNCTION OF MAJOR AND CROSS-STREET VOLUMES AND
CRUISE SPEED - UNSIGNALIZED INTERSECTIONS
Ul
-o
Cross-street
effective lane
vo!u-» (veh/ht)
Elenent
'*> ' V
Tfejor street volosw (vehicles/hoar) cruise speed is 40 su/kr
100
200
?. 01270 0.02977
Q , 0.00213 0.00427
Queue
^00 • Q
V
Queue
500 1 V
300
0.06883
0 . 00640
10.0 40.0 40.0
0.01212 0.02761 ', 0.05200
0.00213 0.00427 0.00640
40.0 40.0 iO.O
0.01222 j 0.02630 \ 0.04512
! (L,, 0.00213
400
Queue
V
V
] Queue
300
V
40.0
0.01209
0.00213
0.00427 0.00640
40.0
0.02545
0.00427
40.0
O.O4157
0.00640
40.0 40.0 40.0
0.01199
! 0^. 0.00213
1 Queue 40.0
200 ' 0^ 0.01192
0
0.00213
1 ^*"
100
Queue '• 40.0
V
V
Queue
0.01186
0.00213
40.0
0.02489
0.00427
0.03951
0.00640
40.0 40.0
0.02450
0.03951
0.00427 0.00640
1
40.0
0.02422
0.00427
40.0
40.0
0.03736
0.00640
40.0
400
0.0
0.00854
-0.0
0.06608
500
0.0
0.01067
40-0
0.0
0.00315 j 0.01067
106.3 ; 40.0
0.08439
0.00854
40.0
0.06567
0.0
0.01067
40.0
0.08110
0.00854 0.00624
40.0 ] 68.4
0.05808
0.08951
0.00854 0.01067
;
40.0 '1 40.0
0.05417 i 0.07547
0.00854
0.01067
40.0 40.0
0.05188
0.00854
40.0
0.06913
0.01067
iO.O
600
700
0.0 0.0
0.01280
0.01494
40.0 40.0
0.0 ' 0.0
8OO
900
0.0 0.0
0.01707
40.0
0.0
0.01280
0.01491
40.0 40.0
0.0 ! 0.0
0.01280 0.01494
40.0 j 40.0
0.6
0.01280
40.0
0.06902
0.0
0.01494
40.0
0.0
0.00353 j 0.01494
!
145.1 ! 40.0
0.11103 0.05998
0.01225 ! 0.00158
j
40.0
0.09313
0.01280
40.0
379.3
0.10622
0.01106
54.0
0.01707
0.01921
1000 j 11OO
O.C - 0.0
0.0.2347
1200
0.0
(•-•32561
40.0 iO.O j 40.0 ' 40.0
0.0
C.O , 0.0
I -
0.01921 ' 0.02134 . 0.02347
4b.O 1 40.0 . 40.0 '. 40.0
0.0
0.01707
40.0
0.0
0.01707
40.0
0.0
0.01707
40.0
0.0
0.01921
4O.O
0.0
0.01921
40.0
0.0
0.01921
40.0
0.0 ' 0.0
0.01707
0.01921
o.c ; o.o
0. 02134
40.0
0.0
0.02134
4O.O
0.02347
40.0
0.0
0.02347
40.0
0.0 • 0.0
0.02134 0.02J47
4O.O 40.0
0.0
0.02134
40.0 > 4O.O ! 40.0
0.05436
0.0039
1729.4
0.0
0.01921
O.O
0.02134
40.0 " 40.0
0.0
0.02347
40.0
0.0
0.02347
40.0
0.0
0.02561
40.0
0.0
0.02561
40.0
0.0
0.02561
40. 0
0.0
0.02561
40.0
0.0
0.02561
40.0
0.0
0.02561
40.0
1300 j 1*00
0.0 • 0.0
0.027T1 0.02988
40.0 40.0
0.0 0.0
0.02774 0.02988
4O.O 40.0
0.0 0.0
0.02774 0.029S8
40.0 40.0
0.0 0.0
0. 02774 0.02988
40.0 40.0
0.0 0.0
O.02774 0.02988
40.0 40.0
0.0 0.0
0.01773 0.02988
40.0 40.0
0.0 0.0
0.02774 . 0.02988
40.0 j 40.0
-------
Table 11 (continued).
TOTAL QUEUE EMISSIONS, (QQT>» CRUISE COMPONENT EMISSION, (QQC>> AND
QUEUE LENGTH AS A FUNCTION OF MAJOR AND CROSS-STREET VOLUMES AND
CRUISE SPEED - UNSIGNALIZED INTERSECTIONS
Cross-street
ef receive lane
voluaw (veh/hr)
1400
1300
1200
1100
1000
9OO
800
V
V
Hajor street volurje
100
0.04072
0.00261
200
0.0
0.00522
Queue iO.O i 40.0
I
300
0.0
0.00782
400
0.0
0.01043
40.0 | 10.0
Q ; 0.02731 0.0 j 0.0 : 0.0
Q ! 0.00261 | 0.00522 0.00782 0.01043
Queue 40.0 '• 40.0 ! 40.0
0 T 6.02182
V
Queue
V
V
Queue
V
V
Queue
V
V
Queue
V
V
Queue
0.00261
40.0
0.01904
0.0
0.00522
40.0
0.05670
0.0
0.00782
40.0
0.0
0.00261 0.00118 0.00782
40.0 1176.9 ! 40.0
0.01745
0.00261
40.0
0.01649
0.00261
40.0
0.01587
0.00261
40.0
0.06894
0.00522
40.0
0.04709
0.00522
40.0
0.03915
0.00522
40.0
0.0
0.00782
40.0
0.0
0.00782
40.0
40.0
500
0.0
0.01304
600
0.0
0.01565
40.0 40.0
1
00
0.01304
40.0
0.0 | 0.0
0.01043 j 0.01304
40.0
0.0
0.01043
40.0
0.0
0.01043
40.0
0.0
0.01304
40.0
0.0
0.0
0.01565
40.0
0.0
0.01565
40.0
0.0
0. 015*5
40.0
0.0
0.01304 0.01565
40.0 ! 40.0
|
0.0 0.0
0.01043, 0.01304
40.0
0.06669 0.0
0.00331
94.4
0.01043
40.0
40.0
0.0
0.01304
40.0
40.0
0.0
0.01565
40.0
0.0
0.01565
40.0
'vehicles/hour) cruise speed is 45 n/fcr)
700 { BOO
900 1 1000
o.o o.c ; o.o o.o
0.01826 0.02086
1100
0.3
0.02347 0.02608 > 0.02868
40.0 40.0 I 10.0 .40.0 -"-0.0
0.0 0.0 . 0.0 0.0 ' 0.0
0.01825 0.020S6 \ 0.02347 0.02608
40.0 40.0 ' 40.0 40.0
0.0 . 0.0
0.01825 0.0208«
40.0 40.0 -
0.0 0.0
0.0 : 0.0
0.02868
iO.O
0.0
0.02347 0.02608 0.02868
40.0 '40.0
•0.0
0.0 :. 0.0 | 0.0
0.01825 0.02086 j 0.02347 0.02608
40.0 40.0 i 40.0 40.0
0.0 0.0
0.0 0.0
0.01825 0.02086 0.02347 0.026OB
40.0 40.0
0.0 0.0
0.01825 0.02086
40.0 40.0
40.0 40.0
0.028(8
•0.0
0.0
0.02868 '
.0.0
0.0 0.0 ' 0.0
0.02347 ' 0.02608 j 0.02868 •
: i i
40.0 :40.0 ; .0.0
0.0 0.0 0.0 ' 0.0 ! 0.0 i
0.01825 , 0.020*6
40. C j 40.0
0.02347 : 0.02608
40.0 140.0
0.02868 i
•0.0
1200
o.c
0.03129
13OO
0.0
0.03390
40.0 | 40.0
•
0.0 0.0
0.03129 0.0339O
*O.O ' 4O.O
0.0 . 0.0
0.03129 ' 0.03390
40.0 i 40.0
o.o : o.o
0.03129 0.03390
40.0 . 40.0
o.o • o.o
0.03129 • 0.03390
40.0 : 40.0
0.0
0.03129
40.0
0.0
0.03129
40.0
0.0
0.03390
40.0 i
0.0 .
0.03190 *
40.0 |
1400
S.S
0. 03651
40.0
0.0
0.01*51
40.0
0.0
0.03*51
44.0
0.0
0.03*51
40.0
0.9
0.03431
40.0
0.0
0.03651
40.0
0.0
0.03*51
40.0
Ul
-------
Table 11 (continued).
TOTAL QUEUE EMISSIONS, (QQT), CRUISE COMPONENT EMISSION, (QQC), AND
QUEUE LENGTH AS A FUNCTION OF MAJOR AND CROSS-STREET VOLUMES AND
CRUISE SPEED - UNS1GNALIZED INTERSECTIONS
Cross-street
effective las*
Toluste (veh/br)
7OO
600
500
4OO
ClMsmt
V
V
Queue
V
V
Qoeoe
V
V
V
i V
300
Quene
V
V
• Qme
200
100
V
V
Qoeue
V
V
Oj—
Xsjor street voluse (vehicle/hour) cntise speed is 45 sn/hr)
100
0.01546
0.00261
40.0
0.01518
0.00261
40.0
0.014*8
0.00261
40.0
0.01485
200
0.03529
0.00522
40.0
0.03313
0.00522
40.0
0.03181
0.00522
40.0
0.03097
0.00261 0.00522
40.0 ! 40.0
0.01475
0.00761
40.0
0.01468
0.00261
40.0
0.01462
0.00261
40.0
0.03040
0.00522
40.0
0.03O01
0.00522
40.0
0.02*74
0.00522
40.0
300
0.07711
0.00782
40.0
0.06027
0.00782
4O.O
0.0533*
O.O07B2
40.0
0.04985
0.00782
40.0
400
0.0
0.01043
500
0.0
0.01304
40.0 40.0
0.07016
0.00385
1O8.3
O.O9543
0.01O43
40.0
0.07670
0.01O43
40.0
O.O477S 1 0.06912
0.00782 • 0.01O43
40.0
0.0464*
0.00782
40.0
0.04564
0.00782
40.0
40.0
0.06521
0.01U3
40.0
O.O62*2
0.01043
40.0
0.0
0.01304
40.0
0.0
0.01304
40.0
0.01*17
0.00763
68.4
0.10330
0.01304
40.0
0.08926
0.013C4
40.0
0.082*3
0.013O4
40.0
600
700
0,0 0.0
0,01565
0.01825
40.0 I 40.0
0.0
0.01565
40.0
0.0
0.01565
40.0
0.0
0.01565
40.0
0.07358
0.00431
145.1
0. 12686
0.01496
41.8
0.10*68
0.01565
40.0
0.0
0.01825
40.0
0.0
0.01825
40.0
0.0
0.01825
40.0
0.0
0.01825
40.0
O.O6201
0.00193
379.3
0.12053
0.01352
54.0
800
0.0
0.02086
900
0.0
0.02347
40.0 40.0
0.0 • 0.0
0.02086 : 0.02347
40.0
0.0
0.02086
40.0
0.0
40.0
0.0
0.02347
4O.O
0.0
0.02086 1 0.02347
40.0
0.0
0.02086
40.0
0.0
0.02086
40.0
0.054*7
O.OOO48
1729.4
40.0
0.0
0.02347
40.0
0.0
0.02347
40.0
0.0
0.02347
40.0
1000
0.0
0.02608
40.0
0.0
1100
:.o
0.02868
40.0
a.o
0.02608 0.02(68
40.0
0.0
0.026O8
40.0
0.0
40.0
0.0
0.02668
40.0
0.0
0.02608 ' 0.02868
40.0 • 40.0
0.0 0.0
0.02608
0.02868
40.0 40.0
0.0
0.02608
0.0
0.02868
40.0 40.0
o.o i o.o
0.02608 ! 0.02868
40.0
4O.O
1200
0.0
1300
0.0
0.03129 i 0.03390
1
40.0
40.0
0.0 , 0.0
0.03129 ' 0.033*0
40.0 : 40.0
0.0
0.03129
4O.O
0.0
0.0
0.03390
40.0
0.0
1400
0.0
0.03651
40.0
0.0
0.03651
40.0
0.0
0.01651
40.0
0.0
0.0312* 1 0.033*0 0.03651
40.0
0.0
0.0312*
40.0
0.0
0.03129
40.0
0.0
0.0312*
40.0
40.0 40.0
0.0 j 0.0
0.033*0
40.0
0.0
0.03390
40.0
0.03651
40.0
0.0
0.03651
40.0
0.0 1 0.0
0.033*0
40.0
0.03651
40.0
-------
Table 12. EMISSION CORRECTION FACTORS FOR REGION, CALENDAR YEAR, SPEED, PERCENT COLD
STARTS (C) PERCENT HOT STARTS (H) AND TEMPERATURE (T) BY VEHICLE TYPE (M)
coMfcno* »*CTIMS run •tciom tu* AIIIIMM
TIMB i«fa i*T8 1978 1978 1980 19*0 1900 I«BO
M H C T
LOV 20 10 20
20 10 80
19 35 20
20 IS eo
20 60 20
20 60 40
40 10 20
«0 10 80
80 35 20
•0 3i 80
80 60 20
40 *0 40
lf»T 20 SO 20
20 10 40
20 15 20
20 35 40
20 60 20
20 60 SO
40 10 20
80 10 40
40 35 20
40 35 40
40 60 20
40 60 40
HC 20 10 20
20 10 40
20 35 20
20 35 80
20 60 20
20 60 40
40 10 20
80 10 40
40 35 20
40 35 40
00 60 20
80 60 40
M06
MOO
0 15 10 84
1.22 1.36 1.37 1.42
1.12 1.1* 1.23 1.26
1.94 2.17 2.39 2.58
1.57 1.74 1.90 2.03
2.65 3.03 3.42 3.7«
2.03 2.30 2.57 2.81
1.24 1.32 1.39 1.4«
1.14 (.20 1.25 1.28
1.96 2.19 2.41 2.60
1.60 1.76 1.92 2.05
2.67 3.05 3.44 3.76
2.05 2.32 2.60 2.83
3.16 3.17 3.35 3.51
2.94 2.9] 3.06 3.18
4.80 5.11 5.65 6.10
4.03 4.22 8.62 4.97
6.43 7.05 7.95 8.70
5.11 5.S2 6.19 6.76
3.21 3.22 3.«0 J.S5
2.99 2.96 3.10 3.23
4.6
-------
Table 12 (continued) .
EMISSION CORRECTION FACTORS FOR REGION, CALENDAR YEAR, SPEED, PERCENT COLD
STARTS (C) PERCENT HOT STARTS (H) AND TEMPERATURE -(T) BY VEHICLE TYPE (M)
cn«"tCTio* FACTJMS FOB »ftli>M HICM
c»
TE*MI
SPttOt
* « C T.
«.OV 20 10 20
20 10 ao
20 J5 20
20 IS 40
20 60 20
20 60 40
*0 lo 20
40 10 4Q
«0 15 20
40 IS 40
40 60 20
40 60 40
1-DT 20 10 20
20 10 4«
20 IS 20
20 IS 40
20 60 20
20 60 00
«0 10 20
40 10 40
«0 IS 20
40 15 40
40 60 20
40 60 40
— *C 20 lo 2
20 10 4
20 IS 2
20 15 a
20 60 2
20 60 a
- _«0 10 2
40 10 4
ao Js 2
40 15 4
40 60 2
40 60 4
unc ""
nuw
KW>
— — — — —
LV6 197* |«78 1970 980 1981 1980 1980 1982 1982 1962 19S2 1984 I9M I9M I9M 1987 198? 1981 1W If** 1999. MM 19*9
o is to is]
.04 1.7J 2.1i 2.44
.'1 I.S6 1.91 ?.?f
.8« i.tH J..4B j.9,
.«8 2.14 2.79 l.|«
.6S «,16 g.81 5.18
.02 J.ll i.(,5 ,,.07
•°' 1.71 ?.l| ?t.77 7.28 8.09 9.02
5,51 5.95 7.17 6.14
'•"•0.1611.6S1J.2J
'.«S 7.88 9.2410.15
».«« «.!S S.«6 6|j|
Hi 7-r s-01 s •"
*-72 7.22 8.62 9.71
|.««> S.90 7.10 8 05
'.5610. 1011. 77ti')j
'."0 7.82 9.1MS;«
1.15 1,09 iy» • .,
>.28 o.,8 1:11 i:i;
> nl ,' * *•*' 2««
2.08 1.45 1.77 2.01
».«0 2.59 1.01 1 40
f-«8 1.91 2.?, j, «,
'?7 i'SS ''" 1'«
i'fl ' 7 U" '•«»
2.66 J.81 2.20 2.50
2.07 1.44 1.76 2.01
1.88 2.58 1.02 1 lJ
2.87 1.92 2.26 2.54
2.16 8.61 8.19 9.46
H-»Q° * ii 0 \ o g 9.7- J >flj
o is J« 45
0.85 l."6 1.76 1.98
0.76 1 .10 1.5ft 1.7*
.51 2.56 2.99 1.15
.21 2.00 2. IS 2.62
2.22 1.65 a. 22 4.68
.66 2.69 1.11 1.46
O.AS 1.46 1.7% 1.97
0.75 1.10 I.S7 1.76
.SI 2.55 2.98 1.12
.20 1.99 2.1« 2.60
1.65 1.94 2.10
?•" ».87 1.,, , ,o
J.76 0.77 0.99 1.1T
'" «!* >.87 2.12
i'fl I'20 '•«* >.«-7
f." 2.26 2.64 2)95
'.78 1.64 J.91 2.16
*.29 8.11 6.29 9.T?
0-n« ",9» DrQ» fttt^
1
o is it «s
0.6% .07 1.26 1.40
0.58 .9* I. IS 1.2*
1.19 .87 3.17 2.40
0.94 .47 l.7| 1.9»
1.71 .67 1.07 I.«8
1.10 .99 2.29 2.5*
0.65 .07 1.26 1.40
0.58 .96 1.11 1.2*
1.19 .87 2.17 2.40
0.94 .47 1.71 1.89
1.71 .67 1.07 1.48
1.11 .99 2.29 2.51
2.88 .74 4.S1 S.I2
2.60 .15 4.08 «.*2
4.95 .42 7.S1 8.41
1.99 .06 5.97 6.68
7.01 .1110.S111.70
5.18 .78 7.86 8.74
2.85 .72 4.49 5.07
2.58 .11 a. OS 4.S8
4.91 .40 7.SO 8.17
1.97 .04 S.94 6.64
7.00 .0910.5011.6*
5.15 .75 7.81 8.70
0.58 .70 0.90 .1.85
O.SO .62 0.80 0.94
1.12 .10 I.SS 1.78
0.85 .99 1.20.U7.
1.66 .89 2.21 2.47
1.20 .16 1.60 1.79
0.57 .69.0.89 1..84.
O.SO .61 0.78 0.9}
1.11 .29 I.S4 1.74
0.84 ,98_ I.|9_1_.JV
1.65 .68 2.19 2. 45
1.1* .15 1.S9 1.78
2.18 7.61 8. 4610. IS
D_^A7 0.97 A All O AT
< 8 t» It 4*
8.4S .8* 8.7) 8.80
0.48 .58 8.»6 8.72
8.84 .IS 1.29 1.42
0.68 .91 1.84 I. IS
I. It .»2 1.86 2.05
0.96 .25 I.4S 1.57
0.46 .6S 8.74 8.81
0.4| .58 8.67 0.71
0.84 .14 I.S8 1.41
0.69 .92 I.8S 1.16
1.21 .61 1.87 2.0*
0.97 .26 1.44 I.S8
1.06 .46 I.7S 1.92
0.96 .SO I.SS 1.71
l.8| .49 2.90 1.2i;
1.46 .96 2.29 2.S4
2.57 .51 4.07 4.SO
1.96 .62 1.01 1.55
1.05 .4S 1.72 I.92J
0.95 .SO I.SS l.72i
1.81 .49 2.89 1.21
1.45 .46 2.28 2.51
2.56 .SI 4.06 4.49
1.95 .62 S.02 S.S4
0.26 .14 8.44 0.52
8.21 .SO O.S9 8.46
8.50 .61 0.76 8.8*
8.18 .48 O.S9 0.67
0.7S .92 1.88 1.28
0.54 .67 0.78 8.88
8.26 .14 0.41 O.SI
8.22 .10 8.18 0.4S
8.58 .61 8.7S 8.8S
8.18 .48 O.S8 8.6*
0.74 .92 1.07 1.28
0.54 .66 8.78 0.87
I.8S S.S2 6.91 7.93
t.Ofc 8.86 6.77 0.74
— i — n — w w
6.17 8.4* 8.52 8.17
0.14 8.42 6.48 8.SI
8.71 8.81 «.9S 1.8*
0.59 0.69 8.79 8.8*
1.04 t.?0 1.18 I.S2
(.US 8.9* |.|8 1.21
0.18 0.47 0.54 8.54
0.15 0.41 8.49 S.%1
8.72 0.84 8.9* I.Of
0.61 0.70 8.88 8.87
1.06 1.22 I.S9 I.S1
8.8* 0.97 l.ll lOX
1.61 2.SI 2.74 S.8S
1.48 2.09 2.4* 2.71
2.77 S.97 4.*8 5.89
2.24 1.IS 1.64 4.01
S.9I b.6l 6.46 7.14
1.00 4.17 4.8| S.S2
1.62 2.11 2.71 1.02
1.47 2.09 2.4* 2.72
2.76 S.«7 4.S9 5.88
2.2S 1.1S ».6» 4.82
1.90 S.6I 6.45 7.18
2.99 4.17 4.80 S.ll
9.14 0.20 0.2* 0.38
8.12 8.18 0.2S 8.27
8.27 0.17 0.45 O.SI
0.21 0.28 0.15 1.J9
8.41 O.SS 8.64 6,71
0.29 0.19 8.46 8.S2
0.14 0.20 0. 25 0.10
0.12 0.17 0.22 8.2*
0.27 0.17 8.4* O.S8
0.21 0.28 O.li-O***
0.41 0.54 0.6! 8.71
0.29 0.19 0.46 O.SI
1.69 4.22 S.ll 6.2S
* tli B 71 B.8.8. fl.fc
.
t » it o*
••••••••••••••8J*B*0»8B
8.SI 9.12 8.S* .M
8.29 8.S8 8.SS .1*
.*! 6.*6 6.*8 .?«
.52 8. 52 8.S9 .M
.98 8.88 1.88 .19
.7* 9.7* 8.88 .91
.12 9.SS 9.17 .88
.18 8.SI 8. IS .IT
.62 *.*! 9.T* .T*
.54 8.S1 8.*8 .»»
.92 8.89 1.82 .11
.7* 9.7S 8.8S .94
.S* 8.85 8.98 .M
.49 8.7* 8.8* .9*
.91 1.45 l.*7 .M
.74 I.IS I.SI .8*
.29 2.05 2.15 .99
..99 I.SI 1.74 .92
.54 0.85 8.M .M
.49 8.76 8.68 .9*
.91 1.45 1.67 .81
.74 1.18 LSI .88
.29 2.9S 2.1S .59
.98 I.SI 1.74 .92
.98 9.IS 8.1* .19
.87 8.11 8.14 .1*
.1* 8.2* 8.29 .11
.12 8.18 8.22 .M
.24 8.SS 8.41 .4*
.17 8.25 8.S8 .11
.88 0.11 8.1* .19
.87 8.11 8.14 .17
.1* 8.2* 8.29 .1*
.12 8.18 8.22 .25
.24 8.15 8.41 .4*
8.17 8.25 8.S8 .11
1.62 1.82 3.79 4.**
t»n "lift* "•-*»" •-**
-------
H*
Ui
VO
Table 12 (continued). EMISSION CORRECTION FACTORS FOR REGION, CALENDAR YEAR, SPEED, PERCENT COLD
STARTS (C) PERCENT HOT STARTS (H) AND TEMPERATURE (T) BY VEHICLE TYPE (M)
(•MBit* CUMWCtltM »AC 10MB t06 BfttlOM C«t!»OMS«
»14»I
•mO
•) H C t
IB» 26 to 20
20 It •»
26 35 20
26 39 «e
26 40 20
20 60 40
•« 10 20
•« 10 «0
•e is 20
40 35 «0
•0 60 ?0
•0 60 40
tot 20 10 20
20 10 40
20 IS 20
iO IS 40
20 60 20
20 60 40
40 10 20
40 10 40
40 35 20
40 15 40
40 »0 20
40 60 40
_"C 20 10 20
20 10 40
20 15 20
20 35 40
20 60 20
20 60 40
40 10 20
40 tO 40
«0 K 20
4« 35 40
«9 60 20
40 60 40
N06
MM
r S * tl ' i? ifffi
.0* i.tr
.Of 1.00
.64 I.TI
.41 I.4S
.19 2. IS
.» 1.91
.It 1.09
.04 1.02
.66 1.7]
.41 1.46
.21 2.37
.•1 1.*)
.2} 3.05
.02 2.04
.05 4.9?
.29 4.16
.67 6.76
.S7 S.49
.11 1.12
.09 2.91
.13 4.99
.17 4.24
.9$ 6.86
.6S S.S7
.66 O.Bl
.60 0.7S
.10 1.39
.87 1.10
.11 1.14
.O/ l.n*
.07 t.o\
.58 1.6*
.64 2.87
.14 2.1?
.11 1.16
.OS 1.06
.89 2..03
.60 1.70
.66 ?.<»0
.16 2.14
.10 1.1?
,64 2.84
.14 5. 6ft
.48 4.71
.59 8.2S
.11 6.61
.17 l.lfl
.«J 2.91
.«! 5.7S
.55 4.60
.66 6.31
.18 6.6H
,9S 1.04
.85 0.94
.58 1.7S
.26 1.3«
,5« 1.94 .22 2.46
.IS 1.45- .66 1.S1
.67 O.fl4 .96 1.05
.60 0.76 .66 0.95
.11 1.39 1.59 1.76
.88 1.11 1.27 1.40
.55 1.9S 2.23 2.46
.16 1.46 1.67 1.114
1.44 9.41 S.77 7.04
9.01 0-61 0-57 0.51
6 i* 10 4)
«.»4 .«! 0.8S 0.47
0.69 .7* 0.7* O.M
1.10 .11 1.46 I.Sf
0.46 .14 J,?S 1.11
1.47 .84 ?.07 2.26
1.2? .S2 1.71 1.66
0.7S .Hi 0.47 O.M
0.71 .7* 0.81 0.*?
I. 12 .IS 1.46 I.S4
0.97 .16 1.27 I. IS
1.46 .86 2.09 2.26
1.21 .55 1.71 1.66
2.81 .69 2.76 2.7*
2.64 .51 2.55 2.5*
4.46 .40 4.60 S.It
1.81 .77 4.06 4.12
6.10 .10 6.64 7.44
5.01 .03 5.61 6.06
2.89 .77 2.61 2.86
2.71 .59 2.61 2.63
4. S3 .47 4.87 S.I9
3,91 .65 4. IS 4.3*
6.17 .16 6.9| 7.51
S.ll .10 5.66 6.IS
0.56 .69 0.76 0.61
0.50 .61 0.67 0.71
0.99 .21 1.16 1.49
0.77 .94 I. OS 1.14
1.42 .71 1.97 2.17
1.04 .26 1.41 1.57
(1.57 .69 0.76 0.62
O.SI .61 0.67 0.7?
1.00 .22 1.37 1.49
0.76 .94 1.06 I.IS
1.41 .74 1.98 2.17
l.OS .27 1.44 1.56
t.ll S.I2 S.90 7.24
0.01 0.61 0.54 O.S4
• It M 99
.46 .** .6} 6.6%
.61 ,S6 ,S» 6.6|
.** .91 .1* |.f|
.SO .M ,9T 1.66
.66 .48 .61 1.7*
.74 .M .39 1.4?
.45 .62 .»« 0.67
.42 .SO .61 6.61
.47 .61 .14 1.2)
.56 .96 .99 1.6*
.69 .45 .61 1.70
.75 .22 .17 J.46
.12 .27 .M 2.3*
14 1% IA 9 £•
• IV • •* .•• *.«v
.71 .75 .19 4.M
.21 .29 ,54 3.7*
.16 .22" .0* 6.U
.26 .16 .69 «
.19 .14 .42 <
.25 .20 .23 i
.76 .62 .17 <
.16 .13 ,»t ]
.17 .24 .91 4
.35 .45 .97 «
.46 .56 .ftl 1
.42 .49 .91 4
.67 .62 .1*
.67 .78 .87 1
.26 .46 .67 1
,9| .07 .21 1
.49 .57 .»! I
.41 .50 .94 1
.68 .61 .19 1
.67 .79 .87 4
1.26 .48 .66 1
0.92 .67 .21 1
i.ll
P.63
titl
•.49
1*6)1
k.43
1.39
1.66
».M
. »»
1.24
)c*4
.64
.32
,65
1.96
.29
>.»•
.84
.33
1.29 4.89 6.*l 7.92
6.61 0.66 6.91 6.9*
6 19 M 49
6.18 .48 (
6.17 .36 <
.26 .73 1
.24 .64 1
.38 .0* 1
.32 .«! 1
.16 .42 1
.17 .46 I
.26 .79 »
.29 .66 1
.36 .86 I
.32 .*2 1
.8| .89 1
T9 BA 1
.77 »99 1
.32 .42
.16 .29
.82 .66 i
.96 .71
.64 .86 I
.86 .83 I
.39 «*6
to .26
. fl V . Kw
.85 .63 i
.99 .74
.26 .2* 4
.23 .29 <
.47 .92 i
.3fc~ .46
. *9 .^w *
.69 .79
.50 .55
>• >•
•C6 *£~ I
.23 ,26
.48 .52 (
»MA
• *» *
•69 8>76
,56 .55
1.46 1
>.4| 1
>.M t
1.72 1
.21 1
.41 1
(.46 1
>.43 1
1.84 1
(.74 1
.22 1
.69 1
1.88 1
(H« m
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•—ax a_~B\ii o.%i> •. si
V 19 M V>
O^tl 6.39 6.36 0.46
6.16 6.32 6.39 6.17
6.17 6.69 8.73 6.7*
8.19 6.57 0.64 6.6*
6.24 0.95 1.06 t.|*
6.26 8.61 6.«2 i.,8*
6.11 6.1* 6.44 6.4X!
6.16 6.14 6.37 0.3*
6.16 6.67 6.ZS 4UM-J
4.19 6.9* 6.«* 6.71 1
6.24 6.97 1.16 l.»|
6^t 6,81 8.«4 1^63-j
1.27 1.46 1.47 1.91
1*21 1.*? !.*• !j"l
2.09 2.46 2.65 2.84
1.66 2.12 2.33 2.48
2.91 J.19 3.62 *Ot-
2.50 2.91 3.27 3.96
i.32 1.46 1.93 1.57
1.25 US6 i.4»^U«I-
2.14 2.45 2.78 2.96
1.96 2.17 2.38 2.94
2.95 J.45 J.66 JU23
2.59 2.«7 3.33 3.62
4).L7. 9.16 O^iOJ^*
4.19 6.16 6.17 6.17
6.32 6.34 8.37 4.46
«,i4_0,2t *,29JJt
0.46 0.49 0.99 6.66
0.33 6.35 0.48 6.43
0TIB 0.19 6.26 6.24
6.19 6.1* 4.17 6.18
8.32 6.34 6.38 6.41
6.24 6.26 6.29 6.11
6.46 0.49 6.59 6.61
0.33 6.36 6.46 8.44
1.29 3.69 4.66 9.61
6.61 6.94 6.92 6.56 j
' 1 11 If •>
4.6* 6.31 8.36 6.3*
6.6* 8.2* 8.32 6.33
8.11 4.99 6.*7 8.73
6.16 4.92 6.98 6.*3
6.1ft 6.67 6.99 1.89
8. IS 6.79 6.89 6.93 .
6.6* 6.32 8.3* 6.38
6.6* 8.3* 0.33 0.39
6.11 6,*1 6.*6 8.76
6.10 0.93 0.M 0.*9
0.1* 6.69 1.01 l.ll
0.14 0.7* 0.07 0.99.
0.49 0.99 0.59 0.*l
8.63 6.92 0.9S 0.97
0.77 0.97 1.98 I.IT
6.69 6.0* 8.99 I.M
1.69 1.39 1.90 1.72
0.94 1.29 1.3* l.*0
0.47 0.90 0.*l 6.M
0.49 0.99 0.90 0.99
0.79 1.00 1.11 1.19
0.70 0.89 9.90 1.09
1.16 1.42 t.»6 1.79
0.4* 1.23 1.30 1.31
6.12 6.13 6.13 *.1*_
6.11 0.11 0.12 0.12
0.23 0.2* 0.2* 9.2*
0.17 6.16 6.26 6.21 _
6.33 6.3* 0.39 0.43
0.24 6.29 6.20 9.30
6.12 6.13 0.14 9.l*_
6.11 0.11 0.12 0.12
0.23 0.24 0.2* 0.2*
0.17 0.10 6.26 0.21.
0.33 6.39 0.39 9.43
0.24 0,29 0.20 0.30
1.30 2.49 3.27 4.10
i6.I3 0.99 0.S2 «.»T.
-------
INTERSECTIONS
^
7
n
i
e
*•
i
K
(
»•
I
9
«
«
i
•
«
b
«.
>
b
2
<
|
1
i
i
WO
800
> T80
*
:
i 700
;
i
' 680
i
i
i
I 800
i
i
i
; 880
>
O
f 800
>
«
t
\ 4««
>
I
a 400
a
M
j
c 380
r
300
280
200,
/
/
/
'
/
1
'
,
J
>
f
1
.
/
I
/
I
f
f
/
/
B 20 80 100 200 300 800 1000
QUEUE LENGTH , L. tm)
Figure 31. Normalized CO concentration contribution from excess
emissions on approach 1 as a function of queue length
on approach 1 for intersections
160
-------
INTERSECTIONS
i
Ul
I
V)
in -
8 ?
w o
CD
£
I
i
Ul
u
s
u
o
kl
ISO
140
130
120
110
100
90
80
70
60
SO
40
30
20
10
20
50 100 ISO 200
EFFECTIVE QUEUE LENGTH, L» (meten)
500
Figure 32. Normalized CO concentration contributions from excess
emissions on approaches 2, 3, and 4 as a function of
queue length on approach 1 for intersections
161
-------
UNINTERRUPTED FLOW
FROM FREE-FLOW EMISSION
E
n
i
o
f\°
ENTRATION
NORMALIZED
900
800
700
600
500
400
300
200
100
0
1
1 1 1 1
\
\
1 1 ' 1
1 1 1 1
\
1 1 u 1
1 1 1 \
\
1 1 1 1
1 1 1 1
X
\
•x
X
^
1
\
1
•*-*.
-^>
0 IS 2O 25 30 39 40 43 50 60 70 BO 90 10
ROADWAY/RECEPTOR SEPARATION , meter*
Figure 33. Normalized CO concentration contribution at each traffic
stream at locations of uninterrupted flow
162
-------
800
700
600
INTERSECTIONS
80°
. 400
•f
51°
-------
700
6OO
600
g 400
•a
i
o
3OO
2OO
IOO
u =lm/sec
10 IS 2O 25 3O
x ROAD/RECEPTOR SEPARATION, meters
Figure 35. Normalized CO concentration in street-canyons
assuming vortex has formed
-------
INTERSECTIONS
IO 2O 3O 40 50 6O 7O 8O 9O IOO HO I2O 130 140 ISO 160 I7O ISO
x ROAD/RECEPTOR SEPARATION, Mt«rs
Figure 36. Distance correction factor for excess emission
contributions at intersections
-------
INTERSECTIONS
1.3
1.2
CD
CC
O
O
O 0.9
u 0.8
iti
ac.
u.
of O.7
o
o
If 0.6
H 0.5
UJ
CC
O 0.4
ui
S 0.3
?
-------
D. SPECIAL INSTRUCTIONS
Presented here are discussions on several topics that are directly relevant
to hot spot analysis. These discussions serve to treat in detail several
areas that are especially important in hot spot analysis, but which were
only briefly discussed in previous sections of this document.
1. Optimum Receptor Siting
The location of the optimum receptor site is at the position where the
maximum projected pollutant concentration is most likely to occur. The
optimum receptor placement may be determined according to the following
guidelines.
Uninterrupted flow locations;
(i) The optimum receptor site is on the side of the road that
has the heaviest peak-hour traffic flow (vehicles/hour).
(ii) The receptor should be located at the minimum perpendicular
distance, x, from the roadway consistent with the criteria
for being a reasonable receptor site. For the purposes of
hot spot verification, the most practical guidance that can
be given is to assume the receptor to be located at the
centerline of the adjacent sidewalk or at the right-of-way
limit if no sidewalk exists.
(iii) Each traffic stream (all lanes in one direction of travel)
should be assigned an identification number with regard
to the receptor site as depicted below.
fi TRAFFIC
STREAM
RECEPTOR
167
-------
Intersection locations:
(i) The receptor should be located on an approach rather than the
departure side of an intersection leg.
(ii) If all such approaches to the intersection have an equal
number of approach lanes, the receptor should be located
on the approach having the highest peak volume.
(iii) If the approaches have an unequal number of lanes, and
the approach having the greatest number of lanes also
has the highest lane volume, the receptor should be lo-
cated on that approach.
(iv) If the approach having the largest number of lanes does
not have the greatest lane volume, Table 9 and Figure 38
must be used to determine receptor placement. Enter Table 9
using the lane volume of the approach having the most lanes
as V to determine the queue length, Le, which develops
on that approach. Use this quantity to enter Figure 38
to determine the normalized concentrations, \H . Next,
designate the largest lane volume as V < and enter Table 9
to determine the queue length which develops on the correspond-
ing approach. Again use Figure 38 to find the resulting
normalized concentration - . The receptor should be
located on the approach which yields the highest P^)
value .
(v) Each traffic stream (all lanes in one direction of travel)
approaching the intersection should be assigned an identifica-
tion number with regard to the receptor site as depicted below.
168
-------
• 00
•00 —
790
TOO
i
h-
i
oe
I
i
aoo
380
a 800
400
380
100
10 20 SO 40 BO TO 100 200 300
OUCUC LENOTH.L, (ml
900 700 1000
Figure 38. CO concentration contribution from excess emissions on
approach 1 as a function of number of lanes and queue
length
169
-------
t
4
(vi) As with the uninterrupted flow location, the receptor
should be located at the centerline of the adjacent
sidewalk or at the right-of-way limit if no sidewalk
exists.
Examples - Three examples illustrating the above principles are shown.
EXAMPLE 1
N
w
t
STOP
SIGN
Given the following data:
Road segment
No. of approach lanes
Peak hour volume per lane
Average cruise speed
(assume intersection in an
outlying business district)
N
1
300
25
S
1
200
25
E
1
500
25
W
1
500
25
170
-------
W-E roadway has uninterrupted flow.
is controlled by a stop sign.
Solution:
N-S roadway flow
Criterion (i) requires that the receptor be located on
the N-S roadway. Since both N and S approaches have an
equal number of lanes (1), the receptor should be located
on the N approach according to criterion (ii). The
traffic streams are then assigned identification numbers
as depicted below according to criterion (v),
®
STOP
SIGN
N
1
1
w
t
2
S
STOP
SIGN
EXAMPLE 2
N
W
t
Road segment N S E
No. of approach lanes 232
Peak hour volume per lane 500 600 500
Average cruise speed 25 25 25
Intersection controlled by a signal.
W
0
171
-------
Solution:
The road segment having the greatest number of approach
lanes (segment S) also has the highest peak hour lane
volume. Hence, the receptor should be located on segment
S based on criterion (iii) and the traffic streams iden-
tified as shown below.
N
Z
u
w
Note: Since the crossroad (E-W) is a one-way street,
segment W has no approach lanes and need not be con-
sidered in the subsequent analysis. However, segment E
is still assigned the No. 4 identification number due
to its relative position with respect to approach
No. 1 (segment S).
EXAMPLE 3
N
U
W
E
ft
Road segment
No. of approach lanes
Peak hour volume per lane
Average cruise speed
Intersection controlled by a signal.
N
2
800
35
S
2
900
35
E
3
600
35
W
1
600
35
172
-------
Solution:
Since the road segment having the greatest number of
approach lanes (segment E) does not have the greatest
lane volume (segment S), a test must be made according
to criterion (iv) to determine the location of the
highest expected CO concentration.
(a) First designating approach E as .the main road:
Vmain - 600 and Vcross » 900. Enter Table 8
at cruise speed 35 and the appropriate lane
volumes. The resulting queue length, Le, on
approach E is 231.0 m. Enter Figure 33 at
Le - 231 m and read the (xu/Q)e value at the
intersection of Le - 231 and "3-lanes" line or
calculate the (xu/Q)e value from the appropriate
equation. In this case, the equation must be
used, so (xu/Q)e - 785 log (Le) - 610 for a
3-lane approach and (xu/Q)e = 1245.4 in this case.
(b) Next designate approach S as the main road:
Vmain = 900 and Vcross = 600. Again use Table 8
to determine the queue length on approach S
(283.9 m). Enter Figure 33 at Le = 283.9 m
and read the value of (xu/Q)e at the intersection
of Le = 283.9 and the "2 lanes" line or calculate
the value from the equation. Once again, the
equation must be used": (xu/Q)e = 575 log (Le) -
400 for a 2-lane approach and (xu/Q)e = 1010.6 in
this case.
(c) The (xu/Q)e value is maximized by locating the
receptor on segment E. The traffic streams
approaching the intersection should be identified
as depiuLed below.
N
4
H
W
tt
173
-------
2 . Cruise Speed
It is recognized that travel speed data are not always readily available
and that the effort required to actually measure travel speed is rather
substantial. Offered here are alternative methods for deriving reasonable
(in the context of hot spot analysis) estimates of cruise speed for various
types of roadways. These methods involve a rather subjective process of
defining speed as a simple function of.lane volume. Figures 39 and 40
present specific speed-lane volume relationships that may be used for
estimating cruise speeds on free-flowing sections of expressways at rural
arterial streets. Table 13 provides suggested ranges of speeds for urban
streets in several settings. Again, the speed estimates derived from these
should be used only in the absence of measured data.
3. Cold Starts
It is likely that information regarding the percentages of vehicles operat-
ing in the cold mode will not be directly available for most areas; there-
fore, this parameter must be estimated. A study13 of the percentages
of vehicles operating in the cold mode at 60 locations in two major
U.S. cities provides the basis for the following general guidance for
estimating the fraction of cold operating vehicles as a function of facility
type and location.
Location and street type
Range of percent of vehicles
operating in the cold-start
mode
• CBD and fringe area; all facilities
• Outer areas; arterials, collectors,
locals
• Core area expressways
• Outer expressways
• Indirect sources
40 to 70 percent
30 to 60 percent
15 to 30 percent
0 to 20 percent
40 to 60 percent
Reflects afternoon peak travel hour conditions.
174
-------
a
E
•
a
ui
UI
a.
ui
V)
ui
(9
a:
ui
70
60
50
40
60 mph — — »
50 mph _. __
40 mph
SPEED LIMITS
u 30
20
10
200 400 600 800 1000 1200 1400 1600 1800 2000
AVERAGE LANE VOLUME, VEHICLES/hour
Figure 39. Typical relationships between average lane volume and
average speed in one direction of travel on controlled
access expressways under uninterrupted flow conditions1
Note: Minimum design standards for controlled access
expressways typically specify design speeds of
70 mph or higher. It should be emphasized that
design speed is used to establish minimum geo-
metric standards to provide a factor of safety
in comparison to the legal speed limits which
control vehicle operation.
175
-------
Q
UJ
UJ
0.
V)
UJ
to
5
u
UJ
ct
UJ
70
60
50
40
30
20
10
-SPEED
LIMITS
•«0mp»,
^—AVERAGE HIGHWAY SPEED
200 400 600 800 1000 1200 1400 1600 1800 2000
AVERAGE LANE VOLUME, VEHICLES /hour
KEY'
AVERAGE HIGHWAY SPEED
SPEED LIMIT
Figure 40. Typical relationships between average lane volume and
average speed in one direction of travel on multilane
rural highways under uninterrupted flow conditions1
Note: Average Highway Speed is the maximum speed at
which a driver can comfortably travel over the
stretch of roadway under favorable weather and
zero volume conditions and maintain safe
vehicle operation. Here again the Average
Highway Speed represents the roadway design
speed. (The legal speed limit cannot be higher
than the Average Highway Speed.)
176
-------
Table 13. CRITERIA FOR SELECTION OF CRUISE SPEED VALUES FOR URBAN
ROADWAYS AND INTERSECTIONS
General location
Operating characteristics
Cruise speed
range,
mph
Central business district;
Fringe business district
Outlying business district;
Dense residential/
commercial land use
Outlying and residential
residential/commercial
land use
Much interference and fric-
tion from pedestrians or
parking and unparking vehi-
cles; closely spaced inter-
sections; individual vehicle
speed nearly always controlled
by speed of the entire traf-
fic stream
Occasional interference and
friction from pedestrians
or parking and unparking
vehicles; nearby intersec-
tions occasionally restrict
flow; individual vehicle speed
somewhat controlled by speed of
entire traffic stream
Infrequent interference or
friction from pedestrians or
maneuvering vehicles, no
interference form downstream
intersections; speed of indi-
vidual vehicle mildly influ-
enced by speed of traffic
stream
. 15-20
20 - 30
25 - 35
177
-------
E. EXAMPLE
An example of the hot spot verification procedure for a signalized inter-
section, School Street at Lexington Street, is presented here. This exam-
ple makes use of Worksheet No. 5, Calculation of CO Concentration at
Intersections. A completed worksheet is presented in Figure 41. Figure 42
provides a sketch of the intersection indicating the orientation of the
approaches and the location of the optimum receptor site.
The first six entries are concerned with recording the 'data required to
perform the hot spot verification. The Lexington Street north approach
has the highest volume; thus, the optimum receptor site is positioned
along this approach. The G/Cy of 0.53 for the Lexington Street approach
is recorded in line 7.b.i and used with the approach volume, 455, to
compute the effective crossroad volume of 330 vehicles per hour. These
two volumes are entered on the appropriate section of Table 9 to determine
^
the queue length (line 8). The free flow emission rate is found in
Table 10 for each approach and entered on line 9. For this example, the
queue length is 41m, and the free flow emission rates in g/m-sec are
0.00392, 0.00278, 0.00227, and 0.00248 for the four approaches.
The normalized concentrations are found using curves in Figure 34, as ap-
propriate and entered in line 10. The distance correction factors,
line 12, are obtained from Figure 37 at the appropriate roadway/receptor
separation distance for the Main Road approaches only; the correction fac-
tor for the cross-street approaches equals 1.0. Since the emission rates
provided in the verification represent a specific set of assumptions re-
garding calendar year, vehicle, type distribution, cold- and hot-start per-
centages, etc., a correction factor must be applied to reflect actual con-
ditions (i.e., the "assumed" actual conditions, which here, are those in-
dicated in the heading data). This factor is determined using Table 12,
*
These volumes are also used later with Table 9 to determine the excess
emission rate.
178
-------
WORKSHEET NO. 5
CALCULATION OF CO CONCENTRATIONS AT INTERSECTIONS
1 of 3
Location: ScHooc Sr. ($> le
ST
AU. Date;
Analysis by: T M.Jj
Checked by:
Assumptions: Analysis Year: | 9fl£
Location: Californiaj X 49 State, low altitude;
49-State, high altitude.
A o.
Ambient temperature:
F.
Percent of vehicles operating in: (a) cold-start mode /Q __;
hot-start mode
Vehicle- type distribution: LDV__7§_%; LPT // %; HDV-G
-------
9. Qf - Free-flow emission rate (g/m-sec)
10.
11.
r i Normalized concentration con-
l.main trlbution from free-flow emis-
sions on main roadway (10~3 m"1)
f
' S
- Normalized concentration.
contribution from free-flow
emission on crossroad
(10-3 m'1)
12. Cdf - Distance correction factor, free-
flow emissions
13. CEf - Emissions correction factor, free-
flow emissions.
14. a. xf i - Concentration contribution
' from free-flow emissions on
main road (mg/m3)
- Concentration contribution
b. X
f,cross
from free-flow emissions on
crossroad (mg/m3)
15. \ - Total concentration from free-flow
emissions (mg/m3)
16. Q - Excess emission rate (g/m-sec)
17- •*»—
O
- Normalized concentration contri-
bution from excess emissions on
approach i (10~3m~1)
18. Cde - Distance correction factor, excess
emissions
19. C.., - Emissions correction factor, excess
emissions
20. Xe j - Concentration contribution from ex-
' cess emissions on approach i (mg/m3)
Main road
Crossroad
0.00392
0.00216
380
1.30
1J5
4-.Z
0.0*27
0.00248
120
1.S3
1.33
0.8
5.0
0.0 £065
520
1.25
o.%
(N /
X*^O
85
1.55
0.%
2-6
40
1.0
O.K
1.0
z«
1.0
0.%
o.5
21. x - Total contribution from excess emis-
sions (mg/m3)
22. x£ i ur ~ 1-hour average concentration
' resulting from vehicle emissions
(mg/m3)
18.3
Figure 41 (continued). Example Hot Spot Verification
180
-------
23.
Xp ft u ~ 8-hour average CO concen-
*» nr tration (mg/m3)
XT, a t.- ~ 8-hour average background con-
B'8"hr centration '-'-^
25.
-------
Ul
Ul
o:
SCHOOL
STREET
o
z
X
Ul
_J
t
Figure 42. Approach orientation and receptor (R) location
182
-------
for 49-atate, low altitude conditions and the conditions described in the
heading data regarding analysis year, location, etc., for each vehicle
type. The individual correction factors for each vehicle type are then
weighted according to the actual percentages observed (or assumed) in the
traffic stream, and a composite factor is derived. In this example, the
individual correction factors from Table 12 are: 0.83, 2.85, 5.23, and
0.6 for LDV's, LDT's, HDV-G's, and HDV-D's, respectively. Weighting these
according to the percentages of each type of vehicle (from the heading
data) yields:
CEf - (0.78X0.83) + (0.11X2.85) + (0.06X5.23) + (0.05X0.6) • 1.33
The concentration contribution from free-flow emissions is computed
separately for each approach for both the main street and the cross street.
For the main street approaches, the free-flow concentration, xf . , is
z )fli£iiLii
computed from the following equation:
Xf ma£n • [(line 10)(line 13)] [(line ShUine 9)i(line 12)i +
(line 3)2(line 9)2(line 12)21=
[(380X1.33)] [(1X0.00392X1.3) + (1X0.00278X1.15)] •
4.2 mg/m3
For the cross-street contribution:
X- • [(line 11)(line 13)1 [(line 3)3(line 9)3 + (line 3)^ (line 9)iJ
CjCirOSSL _J L «J
[(120)(1.33)] [(1)(0.00227) + (1)(0.00248) ] = 0.8 mg/m3
The total contribution, xf> from free-flow emissions is:
xf = xf,main + xf,cross " 4'2 m8/m3 + °'8 mg/m3 = 5>°
183
-------
The next step is to compute the excess emissions correction factor. This
factor is derived in the same manner that the free flow emissions correction
factors are developed, except a speed of 0 mph is used in Table 12. The
excess emissions correction factor thus derived is 0.96.
The excess emission rate, CL,, is computed indirectly using cruise and
queue component emission rates found in Table 9, and appropriate correction
factors. The cruise component, Qnr,, and the total queue component, Q.™,,
Ql/ yi
are obtained from Table 9 based on the highest main road volume of 455
vehicles (from line 5 on the Worksheet), and the effective crossroad vo-
lume of 330 vehicles (from line 7.b.ii. of the Worksheet). The correction
factors applied to Q „ and Q are the free flow emissions correction
QC l}i
factor, C-,,. (from line 13 of the Worksheet), and the excess emissions
tit
correction factor, C (from line 19 of the Worksheet), respectively. The
actual excess emission rate, Q , is then computed by:
(0.02302X0.96) - (0.00221)(1.33) = 0.01916
The normalized concentration contribution from excess emissions for each
approach is determined using Figures 31 and 32, and distance correction
factors are computed for the main street approaches using Figure 36. The
above data are used to compute the excess emissions contribution for
each approach, x •> from:
X • = (Q )(*?) . (Cde).
ei xe Q ei i
The total concentration from excess emissions, then is:
Xe = S.
n-1
184
-------
In this example, x was found to be 11.1 mg/m3. The total 1-hour average
concentration, then, is:
X
+ X • 5.0 + 11.1 = 16.1 mg/m3
f Ae
The 8-hour average CO concentration is computed as the product of 16.1
(the 1-hour average) and 0.7 (a correlation factor), which yields
11.3 mg/m3; this value is recorded on line 23. The 11.3 mg/m3 concentra-
tion is the local traffic contribution to which a background concentration,
2.9 mg/m3, is added to determine the total 8-hour average CO concentration,
which is 14.2 mg/m3. To convert the concentration from mg/m3 to ppm,
14.2 mg/m3 is multiplied by 0.87, which yields 12.4 ppm; this is entered
on line 29.
The results of the verification indicate a hot spot potential at the
Lexington Street - School Street intersection. The highest likely 8-hour
average CO concentration computed for the north approach of Lexington
Street is 14.2 mg/m3 (12.4 ppm).
185
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SECTION V
ADDITIONAL INFORMATION REGARDING THE HOT SPOT GUIDELINES
A. INTRODUCTION
This section provides additional information on two aspects of screening
and verification that are not in the mainstream of the screening and
verification procedures, and hence were mentioned only briefly in earlier
sections. These topics include:
• Refined estimates of background concentrations
• Estimating the frequency of violations of the NAAQS.
B. BACKGROUND CO CONCENTRATIONS
1. Background Concentrations
In Section IV, suggested background concentrations were given for use with
the verification procedure. These concentrations were recommended for cases
where data are unavailable to develop specific local background estimates.
This discussion presents a technique for estimating area-specific background
concentrations, thus bridging a gap between assuming a universally applicable
value and using the more involved techniques for finding a site-specific
background concentration estimate that are presented in EPA's Indirect
Source Guidelines.16'21
186
-------
The following technique uses the bulk CO emission inventory for a region
together with a simple urban dispersion model.22 The bulk CO emission in-
ventory can be obtained either from the total VMT and the FTP emission
factor for the appropriate vehicle age mix, or from published data for
metropolitan AQCR's.23 Published data for AQCR's that do not fall in a
metropolitan area are not appropriate because emissions in these regions
do not display enough areal homoegneity to fit the assumptions of the simple
urban dispersion model used in the following technique.
2. Estimating Bulk Emissions from VMT data
VMT data are perhaps the most abundant data elements available concerning
a road network. They are normally available from state or regional trans-
portation, planning, or highway departments. All that is required is the
total VMT for the region. Once this number is obtained, it is multiplied
by the grams per vehicle mile measured by the FTP for the vehicle age mix
appropriate for the region of interest. National average data may be used
if the local vehicle age mix cannot be obtained. This number (grams of
carbon monoxide) should then be divided by the land area coinciding with
the area covered by the VMT data, and the number of seconds during the time
period for which the VMT apply (generally 1 year). The resulting number
is the average area emission rate (gm/m2 sec). Multiplying by 1000, then,
yields emissions in mg/m2 sec.
Alternatively, data are available for 1970 from the report entitled The
National Air Monitoring Program: Air Quality and Emissions Trends Annual
Report Volume II. Carbon monoxide emission data are given in tons/year/
km2 by AQCR. Multiplying the listed emission rate by 2.88 x 10~5 converts
the emissions to mg/m2 sec.
Emissions calculated by either method should be multiplied by 3/2, since
the bulk of CO emissions from traffic occur approximately between the
hours of 6 a.m. and 10 p.m.
187
-------
3. Background Concentrations Estimates
The method presented below is similar to that given by Hozworth21 for
estimating areal averaged concentrations as a function of mixing height, H,
windspeed, u, and downwind distance from the upwind edge of the region, S.
The major assumptions of this technique are that:
1. Steady-state conditions prevail.
2. Emissions occur at ground level and are uniform over the region.
3. Pollutants are nonreactive.
A. Vertical diffusion from each elemental source conforms to
neutral or stable conditions and concentrations follow a
Gaussian distribution out to a defined travel time that is
a function of H. Thereafter, a uniform vertical distribution
of pollutant occurs as a result of further dispersion within
the mexiing layer.
In the model, two separate stability classes have been assumed with dif-
fusion coefficients for these classes based on those used in both
APRAC-1A24 and APRAC-225 urban diffusion models. Given as a function of
travel time, these coefficients are:
D stability a = 0.5t°'77
z
E stability a = 1.35t°'51
z
where t is the travel time in seconds.
The model treats the city source as a continuous series of infinitely
long cross-wind line sources with pollutants confined within the mixing
layer. As indicated in assumption 5, the model requires two equations
according to whether none or some of the pollutants emitted at ground level
achieve a uniform vertical distribution within the mixing layer before
being transported beyond the downwind edge of the city. The equations are
188
-------
X/Q - 5.641(S/u)°'23 D stability (10a)
X/Q = 0.810(S/u)°'49 E stability (lOb)
when none of the pollutants achieve a uniform vertical distribution, that
is , when
1 "^0
S/u < 1.841H D stability
S/u < 0.358H1'96 E stability
The units are in meters and seconds, with x/Q being sec/m. When S/u is
greater than the indicated value, some of the pollutant achieves a uniform
vertical distribution and the equations become:
X/Q = 6.143H0'3 + -^ - 1.053 ^ — =-- D stability (lla)
2. 92
and x/Q • 0.371H0'96 + - - 0.22 - E stability (lib)
Tables 14 and 15 give solutions to Equations (lOa) or (lla) and (lOb)
or (lib), respectively, for various combinations of windspeed, mixing
height, and travel distance across the region. Values below and to the
right of the dotted lines for each city size are from Equations (lOa) and
(lOb) . Other values are found using (lla) and (lib) .
To calculate the average background concentration, enter the table at the
appropriate mixing height, windspeed, and travel distance to find the
value of x/Q- Multiplying this number by the emission rate found earlier
yields the areal averaged, background CO concentration.
4. Example Applications
As a first example, consider the Boston AQCR. The Trends Report23 gives
a 1970 emission rate of 178.75 tons/yr/km2 of CO. Multiplying by 2.88 x 10~5
converts this to 5.15 x 10 3 mg/m2sec. Using Table 14 for D stability,
189
-------
Table 14. AREAL AVERAGED NORMALIZED CONCENTRATION (SEC/M) -- D STABILITY
CITy SIZE wlNr
(*«) (M/SEC) 50 lOu 150 200
10 1 12U. /4. 61. 55.
2 7o. "9. 44. 42.
3 53. 41. 38. 37.
U 45. 3o. 35. 34.
5 10. 34. 33. 33.
20 1 220. 12u. 94. 80.
? 120. 7u. 61. 55.
5 86. 58. 49. 4t>.
4 70. 49. 44. 42.
5 bO. 44. 40. 39.
30 -1 320. 174. 128. 105.
2 17n. 99. 77. 67.
3 120. 74. 61. 55.
4 95. fa2. 52. 48.
5 80. 54. 47. 44.
40 . .. 1 420. 22'J. 161. 130.
2 220. 124. 94. 80.
3 153. 91. 72. 63.
.
34.
32.
64.
49.
13.
40.
38.
78.
56.
"9.
45.
42.
92.
64.
54.
49.
45.
107.
71.
59.
52.
-M9.
121.
78.
64.
56.
52.
135.
85.
68.
60.
55.
150.
92.
73.
61.
58.
164.
100.
78.
67.
61.
178.
107.
«-3.
71.
04.
400
18.
10.
| 36.
34.
32.
61 .
18.
13.
10.
1 38.
74.
55.
48.
44.
42.
87.
61.
53.
48.
45.
99.
68.
57.
51.
48.
112.
74.
61.
55.
51.
124.
80.
66.
56.
53.
137.
87.
70.
61.
56.
1U<).
93.
74.
65.
59.
162.
99.
76.
6«.
61.
450
48.
| 40.
36.
34.
32.
60.
48.
43.
| 40.
38.
71.
51.
48.
44.
42.
82.
60.
52.
48.
45.
94.
65.
56.
51.
48.
105.
71.
60.
54.
50.
116.
77.
64.
57.
53.
127.
82.
67.
60.
55.
138. -
88.
71.
63.
57.
149.
94.
75.
65.
60.
500
47.
40.
36.
34.
32.
59.
47.
43.
40.
38.
69.
53.
47.
44.
42.
79.
59.
51.
47.
45.
89.
64.
55.
50.
47.
99.
69.
59.
SJ.
50.
109.
74.
62.
S6-.
52.
119.
79.
65.
59.
54.
-129.
84.
69.
61.
56.
139.
f»9.
72.
64.
59.
-------
Table 15., AREAL AVERAGED NORMALIZED CONCENTRATION (SEC/M) — E STABILITY
CITY SIZt
10
30
10
50
-7fl
ao
-90
100
WIND SPKED
(M/SF.C)
2
3
4
5
1
2
3
3
a
S
t
2
3
.a.
5
1
2
3
1
2
3
. .u
5
_ 1
2
3
a -
5
1
2
3
4
5
1
I
3
50
lie.
65.
"9.
uo.
35.
216.
I 16.
£2.
65.
55.
316.
166.
116.
91.
76.
116.
216.
14.9.
1 16.
516.
266.
182.
111.
116.
616.
316.
216.
Ibb.
136.
716.
366.
219.
191.
156.
816.
«lo.
282.
-216.
176.
9Jfa.
466.
316.
241.
196.
1016.
5<«.
149.
Z6f.
216.
100
79.
53.
43.
1 37.
34.
130.
79.
62.
53.
47.
180.
105.
'9.
66.
5S.
230.
130.
96.
79.
69.
281.
155.
113.
92.
79.
331.
ISO.
130.
105.
90.
381.
205.
147.
117.
100.
431.
230.
16U.
130.
110.
481,
256.
180.
143.
120.
531.
281 .
197.
155.
130.
- 150
74. r~
53.
43.
37.
34.
HO.
74. p
60. 1
1 "'
' 47.
144.
92.
74. r
64. 1
FIT.
178.
110.
86.
PIT:
211.
127.
98.
83.
74. |
- -245.
144.
110.
92.
81.
278.
161.
121.
101.
89.
312.
178.
133.
110.
96.
34S.
194.
l«u.
118.
103.
378.
211.
155.
1ST.
110.
200
74.
53.
43.
37.
34.
104.
74.
61.
53.
47.
131.
90.
74.
64.
58.
157.
104.
85.
74.
66.
183.
118.
95.
82.
74.
208.
131.
104.
90.
80.
233.
144.
113.
-97.
87.
259.
157.
122.
104.
93.
284.
170.
131.
111.
99.
309.
183.
14*1.
111?.
1,04.
MIXING
250
74.
53.
43.
37.
34.
103.
74.
61.
53.
47.
127.
J 90.
74.
64.
58.
149.
103.
85.
7«.
66.
170.
116.
95.
82.
74.
191.
127.
103.
90.
1 81.
211.
138.
112.
97.
1 87.
232.
1«9.
119.
101.
| VJ.
252.
159.
127.
no.
9t».
272.
170.
1 ?«.
116.
103.
HEIGHT
(M)
300
74.
53.
43.
37.
327.
90.
74.
64.
58.
146.
104.
85.
74.
66.
162.
116.
95.
82.
74.
177.
127.
104.
90.
81.
192.
136.
112.
97.
87.
206.
146.
119.
104.
93.
220.
154.
127.
110.
99.
233.
162.
133.
116.
104.
450
74.
53.
43.
37.
34.
104.
74.
61.
53.
47.
127.
90.
74.
64.
58.
146.
104.
85.
74.
66.
163.
116.
95.
82.
74.
177. 1
127.
104.
90.
81.
191.
136.
112.
«_ -
87.
204.
146.
119.
104.
93.
217.
154.
127.
110.
99.
230.
_J 163.
133.
116.
104.
500
74.
S3.
43.
37.
34.
104.
74.
61.
S3.
47.
J37.
90.
74.
64.
50.
146.
104.
85.
74.
66.
163.
116.
95.
82.
74.
478.
127.
104.
90.
81.
191.
136.
112.
- 97.
•r.
204.
146.
119.
104.
93.
216.
154.
127.
110.
99.
228.
163.
133.
116.
104.
-------
with a mixing height of 100 m, a windspeed of 1 m/sec, and a travel dis-
tance of 90 km, the areal averaged normalized concentration is found to be
474 sec/m. Multiplying this by the emission rate yields:
(474) x (5.15 x 10~3) = 2.4 mg/m3 of GO
Multiplying by 3/2 to account for the nonuniformity in traffic gives a
final 1970 value of 3.6 mg/m3. Applying a 1970 to 1975 average emission
rate correction factor of 0.7, the average background is 2.5 mg/m3.
As a second example, the Washington, D.C. AQCR (National Capital) encom-
passes an area of 5,964 km2 and had CO emissions estimated at 232.72
ton/yr/km in 1970. Assuming the AQCR to be roughly circular, the travel
distance is again about 90 km. Using Table 15, x/ Q is 481 sec/m, assuming
a 100 m mixing height and a 1 m/sec windspeed. Making the appropriate
correction, the emission rate is:
(232.72) x (2.88 x 10~5) x (3/2) = 1.01 x io~2 mg/m2 sec
The average background concentration is then:
(1.01 x 1Q-2) x 481 = 4.9 mg/m3
for 1970, or
(4.9 mg/m3)(0.7) = 3.4 mg/m3
for 1975.
C. EVALUATION TECHNIQUES FOR DETERMINING THE FREQUENCY OF EXCEEDING NAAQS
The problem of determining the frequency of standards exceedance is basically
one of finding how often the requisite traffic and meteorological conditions
that lead to a violation of the NAAQS occur jointly. The carbon monoxide
192
-------
concentration, x, at a hot spot location is a function of the wind-roadway
angle, 9, the windspeed, u, the atmospheric stability class, S, the initial
vertical dispersion parameter, a^, the traffic conditions leading to a
line source emission rate, Q, and the road-receptor distance, x:
X = f (8, u, S, 0 Q, x)
zo
Values of these parameters fall in the
ranges:
0° < 6 < 90°
< u
S111 <_ S <_ s" assuming some continuous measure of stability
1.5m < a < 5m
— zo —
0 1 Q 1 Q", where Q" is the maximum possible line source
emission rate for the roadway
and
0 < X.
As noted, not all combinations of values of these parameters will lead to
a violation of the standards. Furthermore, there are values of the
individual parameters for which a standard violation could not occur,
no matter what values the other parameters take. For example, a 1-hour
standard violation would certainly not occur with a windspeed, u, of
10 m/sec. Denoting these critical values of the parameters with primes,
the values leading to standards violations fall in the ranges:
o <_ e <_ e' <_ 90
0 < u <_ u'
S1" < S' < S < S" assuming some continuous measure of
~ ~ ~~ , stability with S111 being least stable
!-5m 1 azo 1 °zo 1 5m and S" being most stable
0 <_ Q1 <^ Q <_ Q"
and
0 < x < x"
193
-------
If the joint frequency function of concentration values f (x) = f (0, u,
S, QZO, Q, x) is known, then the probability of a violation of a standard
is given by:
f(9,u, S,a ,Q,x) dSdudSda dQdx.
ZO zo
0 o
Finding such a joint frequency function would, of course, be extremely
difficult in practice. If the variables were independent, one could
possibly find the frequency function of each variable and then find the
product of the integrals of the functions of each variable. However,
they are not independent; stability and the initial vertical dispersion
parameter are both functions of windspeed, for example. Stability is
not, in practice, a continuous parameter but rather is separated into
discrete classes. Additionally, variations in other parameters can tend
to move together; for example, windspeed and emission rates are both
likely to be lower at night and higher during the day. Hence, for appli-
cation, the method of determining the frequency of violation of the
standards requires simplifying assumptions.
As a start, the road-receptor separation at a given hot spot location
will generally be some given, fixed value. According to the Indirect
Source Guidelines, the value of the initial vertical dispersion parameter
is 5 m in urban locations, and 5 m in suburban locations unless the
line source is removed from neighboring buildings by at least 10 times
the building height. In this case, a equals 1.5 m. Also, only
ZO
stability classes D and E are considered as possibly leading to a
violation of the NAAQS. Thus, x is fixed, S may take on two discrete
values, and a may have one value for urban areas and two discrete
' zo
values for suburban areas, but only one of these values will pertain to
a particular location. Since the frequency of occurrence of the fixed
194
-------
values of x and a =1. independent of the other variables, the joint
zo
frequency function can be rewritten for the remaining variables only:
F(x) = f (8, u, S, Q)
From this point, an analysis can be made of historical meteorological data
to find how frequently different values of 0, u, and S occur. To start
with, an objective scheme can be used to determine how often D and E
stability classes occur. Then, for times when these stability classes
do occur, the distributions of 0 and u can be found. Since 6 and u are
not really independent, the frequency ideally would be generated in terms
of the joint occurrence of a windspeed and a wind angle during periods of
atmospheric stability class D and periods of atmospheric stability class E.
Though not totally accurate, it is reasonable to assume that the traffic
conditions leading to different emission rates, Q, are independent of
the meteorological parameters. In general, traffic at a given location
varies with time of day and day of week (weekday, Saturday, and Sunday).
The frequency of values of Q can then be generated by time of day for
weekdays, Saturdays, and Sundays. This implies that the meteorological
data frequencies should also be known by time of day. At this point, it
is possible to say how often each stability class occurs, and that during
the occurrence of each stability class, a certain windspeed and wind angle
occur at a given time of day with known frequency.
Knowing the combinations of u, 6, S, and Q that lead to a violation of
the standards, it is now possible to say how frequently, during some time
period such as a year, the standards are likely to be violated.
An additional confounding factor should be discussed here. This involves
the line source emission rate, Q. At intersections, the line source
emission rate (and the peak carbon monoxide concentration) depends on
the type of control at the intersection, volume on the cross street,
195
-------
queue length, and delay: as well as on the volume of traffic on the
street under consideration. In practice, it would be extremely difficult
>rO'
to determine the*&fluence of all these factors on the emission rate,
carbon monoxide concentrations, and the frequency with which variations
in these factors occur. This problem does not exist for free flow sec-
tions of a roadway where emissions depend on the traffic volume (and
speed) on that roadway only. At the intersection, the interaction of
queue length and wind angle on concentrations make it impossible to use
a single range of wind angles in considering conditions leading to
violations of the NAAQS. Different ranges of wind angles are important
for different queue lengths, that is, for different spatial variations in
Q, To simplify this problem, the assumption could be made that the emis-
sion rate is constant along the line source irrespective of the actual
changes that do occur along an approach owing to variable operating
characteristics (queuing, accelerating, etc.).
With the above assumption, it is possible to get an idea of how frequently
the NAAQS are likely to be violated at a hot spot location. The only
remaining information needed pertains to the values of the parameters
that lead to violations. Figure 43 can be used to help determine these
values. Figure 43 shows curves of constant Q as a function of wind-road
angle on the ordinate and windspeed on the abscissa. These values of Q
will lead to a 1-hour average concentration of approximately 14.3 mg/m3 for
stability class D, a road-receptor distance of 10 m, and initial vertical
dispersion of 5 m. Applying the persistence factor of 0.7 (discussed
previously) to the 14.3 mg/m3.hourly concentrations results in an estimated
8-hour average concentration of 10 mg/m3. Figure 43, then, actually shows
wind-road angle, wind speed and emissions rate combinations that result
in potential violations to the 8-hour standard (10 mg/m3) for CO.
196
-------
M
«
Q>
ui
o
I
o
I
o
901
80
70
60
50
40
35
30
25
20
15
10
Q =0.030
\
Q sO.025
\
XQ«0.02I
\ \
IQeO.OIS
A \
QsO.016
V \ \
3 4 56789 10
WINDSPEED, m/sec
15 20
Figure 43. Lines of constant emission rate yielding violations of the
8-hr CO standard as a function of windspeed and wind angle
197
-------
Example
An example problem may be helpful at this point. For this example, con-
sider the School Street at Lexington Street intersection discussed in the
vertification section. Assume that an analysis of historical data
resulted in identifying the probabilities of certain average windspeed
and wind angle (expressed as wind/roadway angle) combinations, as shown
in Table 16.
Table 16. ASSUMED PROBABILITIES OF HOURLY WINDSPEED/WIND ANGLE
COMBINATIONS OCCURRING AT THE LEXINGTON STREET -
SCHOOL STREET INTERSECTION
Windspeed
(m/sec)
1
2
3
4
5
6
it
etc.
Wind direction (as wind-road angle)
0°
0.000
0.000
0.001
0.001
0.004
1°
0.002
0.003
0.001
0.001
0.004
0.002
2°
0.001
0.002
0.002
0.001
0.003
0.004
3°
0.002
0.000
0.000
0.003
0.003
0.005
4°
0.003
0.001
0.002
0.003
0.002
0.003
5°
0.008
0.005
0.003
0.002
0.004
0.004
6°
0.006
0.004
0.002
0.001
0.003
0.003
7°
0.003
0.002
0.001
0.003
0.006
0.004
8° ...
etc.
0.004
0.006
0.002
0.001
0.003
0.005
Assume further that the probability of stability class D occurring during
the peak hours is 1.000.
From the verification computations shown in Figure 41, it can be seen
that the maximum 1-hour average concentration from vehicle emissions at
the intersection is 16.1 mg/m3. Referring to Figure 33, the normalized
concentration from free-flow emissions is 870 * 10~3 m"1 at 10 meters.
The free-flow emission rate, Q, is equal to the receptor concentration,
16.1 mg/m3, divided by the normalized concentration from free flowing
traffic, 870 x HT3 m"1, which equals 0.0185 gm/m sec. Figure 43
198
-------
shows the combinations of windspeed and wind/road angle for various emis-
sion rates that would result in a 1-hour average concentration of
14.3 mg/m3, which, in turn, would violate the 8-hour standard (again,
applying the persistence factor of 0.7 to 14.3 yields of 10.0 mg/m3).
From Figure 43, it can be seen that, when Q has a value of 0.0185, the
8-hour CO standard will be violated only when the windspeed and direc-
tion (relative to the axis of the road) are 1 meter per second and
5 to 7 , respectively. Looking at Table 16 it can be seen that the
probabilities of windspeed-wind direction combinations of 1 meter per
second and 5 , 1 meter per second at 6°, and 1 meter per second at 7°,
are 0.008, 0.006 and 0.003, respectively.
The probability of these combinations of conditions occurring on an annual
basis can be computed as:
P = (y) C^) (0.008 + 0.006 + 0.003) = 0.00051
where •=• accounts for the assumption that the Q value used reflects
workday traffic emissions and that the Q value for weekend
traffic would be significantly lower; and
i
-jr accounts for the assumption that the Q value used is the
maximum value for the day/ hence, occurs only once in 24 hours.
The number of times that the 8-hour standard is likely to be exceeded is:
(0.00051)(365 day/year)(24 hour/day) « 4 times per year
Additionally, one would also have to consider the hourly traffic patterns
that would yield emissions rates of from 0.016 to 0.0185 (these would
possibly occur during hours other than peak hours), and compute the
probabilities in the same manner as for the peak hour shown above. This
actually would indicate the number of hours during the year when emissions
rates are at least 0.0016 (which, according to Figure 43 is the threshold
emission rate) and the appropriate windspeed and direction parameters are
coincidental (hence, 8-hour average CO concentrations are likely to be
10 mg/m3, or greater). What this would not indicate, however, are the
number of nonoverlapping 8-hour averaging periods occurring annually; rather,
all 8-hour averaging periods would be Indicated.
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SECTION VI
APPLICATIONS OF THE HOT SPOT GUIDELINES
A. PLANNING OR EVALUATION OF LOCATIONS FOR AMBIENT CO MONITORING
1. Introduction
The guidelines presented here can be used to assess the degree to which
ambient CO monitoring instruments are representative of the CO concentra-
tions at hot spots. This discussion provides suggestions for how to use
these guidelines to evaluate either present or possible future locations
as to their suitability for CO monitors.
This discussion should be considered as a supplement to the other EPA
guidance on placement of air quality monitors. In particular, placement
of CO monitors should be in accordance with:
• Guidance for Air Quality Monitoring Network Design and
Instrument Siting (Revised). OAQPS Number 1.2-012.
July 1975. Monitoring and Data Analysis Division, Of-
fice of Air Quality Planning and Standards, U.S. Environ-
mental Protection Agency, Research Triangle Park, N.C.,
(hereinafter referred to as OAQPS 1.2-012).l2
• CO Siting. Supplement A to OAQPS 1.2-012. Monitoring
and Data Analysis Division, Office of Air Quality Plan-
ning and Standards, U.S. Environmental Protection Agency,
Research Triangle Park, N.C., (hereinafter referred to as
Supplement A). 3
The present discussion is intended to aid in the review of alternative
monitoring locations from the standpoint of their suitability for various
types of monitoring objectives. However, to decide if a monitor should be
200
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at one intersection or another, or near one highway or another, or to evalu-
ate the exact physical location such as side of street, height of probe, or
lateral placement from curb, these guidelines should be used together with
OAQPS 1.2-012 and Supplement A.
In using these guidelines to review CO monitor placement, it is important
to keep certain key points in mind:
• These guidelines.provide an estimate of the maximum CO
concentration likely to occur near the location in
question. The calculated CO level may not be the very
highest that could ever occur, but can reasonably be
expected to be representative of the highest several
periods in the year.
• These guidelines do not indicate exactly where in the
vicinity of an intersection or midlock location that
the peak CO level will occur; the analysis assumes a
standard, conservative wind direction which may not
coincide with actual prevailing winds. Thus, there is
little or no physical meaning to the association of
each leg of an intersection with a particular CO level.
That is, the verification estimate procedure produces
a series of CO level estimates, the highest of which is
representative of the potential for CO concentrations
near that location..
• In contrast to what the guidelines indicate, actual
peak CO level will tend to occur in an area downwind
from a hot spot, the exact location depending upon wind
direction and speed, building arrangement, topography,
and location of other CO sources.
• Thus, air quality monitors will measure the CO levels at
only one particular location near a hot spot, but may
not identify the maximum CO concentration. The screening
guidelines will estimate the maximum CO concentration but
will not show where it occurs. The relationship between
the two will therefore depend on the details of local
circumstances.
201
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2. Overall Procedure
In order to use this document for evaluating either existing or future
monitor locations, it is recommended that the following sequence of steps
be followed. The sequence of steps is also portrayed in Figure 44.
1. Identify the type of site in question. OAQPS 1.2-012 and
Supplement A define several types of CO monitor sites. Which
type is intended depends upon the ultimate use of the data,
and upon the overall network design. The types of monitors
that are defined in OAQPS 1.2-012 are:
• Street Canyon
Peak
Average
• Neighborhood
Peak
Average
e Corridor
• Background
Determine whether the physical characteristics of the site
are suitable for the intended purpose of the monitoring site.
Supplement A discusses microscale questions such as probe
height, exposure to prevailing winds, and other issues that
must be resolved independently of the question of hot spots.
Determine how estimated CO levels for the site(s) in
question compare with those at other locations in the
area. At this point one would use information from the
CO hot spot screening procedure to determine whether a
particular site is likely to be among those with the
highest CO levels, lowest levels, and so on. This will
be discussed in more detail below.
Determine whether the site in question satisfies the
requirements for the particular monitor type. Using
information from both steps 2 and 3, one can tell if
a particular monitor location is appropriatek and if
not, how well it satisfies the criteria for one or
another monitoring type.
202
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OAQPS 1.2-012
AND SUPPLEMENT A
CO HOT SPOT
GUIDELINES
IDENTIFY TYPE OF
MONITORING SITE
PERFORM SCREENING
OF AREA IN QUESTION
DETERMINE WHETHER
PHYSICAL CHARACTERISTICS
OF SITE ARE SUITABLE
FOR INTENDED TYPE
PERFORM VERIFICATION
ESTIMATE FOR AREA
IN QUESTION
DETERMINE HOW
ESTIMATED CO LEVELS
FOR SITE COMPARE WITH
OTHER LOCATIONS IN AREA
DETERMINE WHETHER
SITE SATISFIES THE
REQUIREMENTS FOR
MONITORING TYPE
Figure 44. Block diagram of process to review monitoring locations
203
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3. Use of Hot Spot Analysis
In Step 3 above, one would use the results of a hot spot analysis, including
both preliminary screening and verification estimates, to see how various
locations in a given area compare as to CO levels. In this case, "area"
means whatever geographic territory it is intended to represent with the
monitor(s) in question, whether it is an entire metropolitan area or some
small part of it. The hot spot analysis may have already been done for
other reasons.
It will be useful to prepare a table that displays the distribution of
calculated CO levels for all the evaluated locations. An example of
such a display is Table 1.7. This frequency distribution allows one to
obtain a perspective on the representativeness of one location compared
with the others.
As an illustration, suppose in the Table 1.7 example there is a monitor
adjacent to an intersection whose 8-hour average CO level has been estimated
by procedures in this volume to be 19.4 mg/m3. From the tabulation of data
for other sites in the same yicinity, Table 1.7, it can be seen that the
monitor location is one whose estimated CO level is exceeded by at least
six other sites of the 51 for which analysis was done. Thus, the cal-
culated concentration of 19.4 mg/m3 at the hypothetical monitor location
is exceeded by at least 11.7 percent of the evaluated sites. Also, there
are seven locations with calculated concentrations within 2.0 mg/m3 (above
or below) of the range in which the monitor falls. On the other hand, the
calculated level exceeds the levels for 43 of those locations that were
*
Note that the monitor itself may provide CO readings considerable less
than that calculated for the adjacent intersection, depending upon the
monitor's location relative to the potential hot spot (height, lateral
separation, leeward versus windward side, etc.). Such microscale derails
must be considered but are separate from the overall locational issues
being addressed here.
204
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evaluated, and presumably exceeds the levels for all locations that were
not screened because of their obvious low potential as hot spots.
Table 17'. HYPOTHETICAL EXAMPLE TABULATION OF CALCULATED CO LEVELS
Range of estimated
8-hr average CO „
concentration, mg/m
<9
9.0 - 10.9
11.0 - 12.9
13.0 - 14.9
15.0 - 16.9
17.0 - 18.9
19.0 - 20.9
21.0 - 22.9
23.0 - 24.9
25.0 - 26.9
27.0 - 28.9
>29.0
Number of
locations
in range
21
5
5
5
4
3
2
2
2
1
1
0
Number of
locations in or
above the range
51
30
25
20
15
11
8
6
4
2
1
0
Having compared the CO concentrations estimated for various locations,
one would next determine whether the site in question satisfies the re-
quirements for a monitor of the type involved (Step 4). For this deter-
mination, it is necessary to consider both the physical characteristics
of the site - evaluated in Step 2 but not discussed in detail here - and
the CO characteristics as shown by Step 4.
Following the example given here, suppose that the hypothetical monitor
location being discussed is intended to be a "peak station" in the sense
used in OAQPS 1.2-012 and Supplement A. The OAQPS guidelines say that
peak stations are to be representative of a number of similarly highly
congested locations. How well does the hypothetical location satisfy
this criterion?
205
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In Step 3, we saw that there are six locations calculated to have CO con-
centrations of more than 21.0 mg/m3, out of 51 locations evaluated. Thus,
the calculated concentration of 19.4 mg/m3 at the hypothetical monitor
location is indicative of several locations but is not the worst potential
hot spot. Tentatively; it would be reasonable to conclude that the monitor
is a suitable location for a peak station. This tentative conclusion must
be confirmed by also examining the type of locations involved, and the de-
tails of the monitor's placement. Supplement A recommends several con-
siderations, and also refers to a report that discusses issues such as
wind direction relative to street orientation, use of a dispersion model
for evaluations, and other details.
One factor of concern to microscale location of monitors, namely, lateral
separation from the intersection, can be examined in part with these hot
spot guidelines. The effect of lateral separation is demonstrated by
Figures 36 and 37. These graphs should be used to estimate the ratio
between the maximum CO concentration likely within the vicinity of the
hot spot (as calculated with these guidelines) and the CO levels measured
by the. monitor. This ratio is only an estimate because these guidelines
do not allow for determination of specific wind direction effects. Such
effects will affect actual monitor readings and should be considered in
monitor placement (and data interpretation) as described in the OAQPS
1.2-012 guidelines.
As an example, using our hypothetical location, suppose that the monitoring
instrument inlet is 25 meters from the centerline of the roadway. Suppose
further that a midblock location is involved. Using Figure 37, the dis-
tance of 25 meters corresponds to a correction factor of about 0.55. Thus,
the calculated level of 19.4 mg/m3 would be estimated as (0.55)x (19.4) = ,
10.7 mg/m3 at the monitor inlet. (If the monitor inlet were adjacent to
an intersection, this adjustment should be performed for both nearest
206
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intersection legs, and the higher value used.) This distance correction
allows for approximate correlation of measured and calculated CO con-
centrations. In this connection, it is apparent that a monitoring in-
strument that is intended to measure peak CO levels should be rather close
to the street, consistent with being a reasonable receptor site.
B. EVALUATING AREAWIDE CONTROL MEASURES
While the hot spot screening and verification procedures are designed
primarily for the rapid identification and substantiation of localized
carbon monoxide hot spots, they may also serve as a primary input to the
planning and evaluation of areawide measures to obviate hot spots. In
particular, this section discusses how to use the guidelines to evaluate
the effects of the Federal Motor Vehicle Emission Control Program (FMVECP),
inspection and maintenance programs (I/M), and retrofit programs. The
types of questions that might be answered by the following evaluation
methods include:
• If there are X hot spots in year Y, how many will there be
in year Z due to the effects of the FMVECP?
• If there are currently X hot spots, how many will be
eliminated by the planned I/M criteria?
• To eliminate Y out of X hot spots, what must the I/M
criteria be?
• How many hot spots will be eliminated by the implemen-
tation of a retrofit program?
Questions involving the effects of traffic flow or traffic volume changes
require only a straightforward reapplication of the procedures and are not
discussed here. Additionally, these measures have localized effects (with
the exception of measures like shifts to mass transit or carpools) and are
not relevant to the discussion of areawide measures.
The following methods assume that the verification procedures have been
carried out.
207
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1. Effects of the FMVECP
The effects of the FMVECP are included in Table 12. The capability for
applying the verification procedure for any year from 1978 through 1990
is provided in the emission correction factors provided in Table 12.
Local vehicle mix data must be included as in the verification techniques
described previously. Only then can Table 12 be used properly to identify
the effects of FMVECP.
2. Effects of I/M
Three methods are available for considering the effects of an I/M program.
The first method, which is preferred and most accurate, is to use the
computer programs described in Carbon Monoxide Hot Spot Guidelines,
Volume IV: Documentation of Computer Programs to Generate Volume I Curves
and Tables.^ These programs were used to generate the screening curves
and tables of correction factors and excess emission rates presented in
this document. The programs are capable of calculating screening curves,
tables of excess and cruise emissions, and emission correction factors
that assume the implementation of a specific I/M program. They are also
capable of calculating tables and curves that are specific to a certain
region's vehicle age and travel distribution, vehicle mix, etc.
The second method is to calculate the excess and cruise emission rates
by hand using the same methodology as that employed in the program. The
methodology is described in Volume II of these guidelines. Since it
could easily take a day to calculate by hand the excess and cruise emis-
sion rates for one verification analysis, this is an appropriate method
if only one analysis is being done or if the speeds, temperatures, cold
and hot starts, and calendar years do not vary among several verification
analyses. Considering the number of calculations involved, it is subject
to some error.
208
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A third possibility is to apply a correction factor to the composite
excess emission rates and cruise emission rates. This is definitely
an inaccurate procedure and is not recommended. One may wish to employ
it to obtain an approximation before proceeding with a more detailed
calculation, however. The procedure for doing so is to first calcualte
the FTP composite emission factor and the idle emission factor for
scenario (i.e., year, cold starts, speed, etc.) of interest without
implementation of I/M. Call these factors £.,„„ and ET_.T_. Next, calcu-
r lr
late the emission factors for the same scenario with the implementation
of I/M. Call these values E and E . In verification procedure
FTP
adjust the excess and cruise emission rates, 0_ and Qf., as follows:
E 1
IM
FTP
EFTP
Qe' -
Enter Qf.' and Q ' on lines 9 and 16 instead of Qf. and Q
3. Effects of a Retrofit Program
The effects of a retrofit program will be similar to those of I/M, except
that only early model year vehicles will be affected. There is no guidance
in AP-42 regarding allowances. Once reasonable allowances are derived from
the design of the program the procedure used for I/M may be applied to de-
termine the effects on the number of potential hot spots.
209
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SECTION VII
EVALUATION OF THE HOT SPOT GUIDELINES
A. INTRODUCTION
This section summarizes an evaluation of the procedures presented in the
Hot Spot Guidelines and presents illustrations of the application of the
guidelines procedures. The evaluation is meant to determine, by way of
comparing guideline procedure results with measured CO concentrations,
whether the guidelines serve their intended purpose; that is, whether
they identify potential hot spots.
It should be noted that an extremely detailed validation study is vir-
tually impossible using existing monitoring data from either permanent
or temporary stations. The guidelines procedures assume a receptor loca-
tion that depends on traffic volumes, traffic signal parameters, traffic
flow parameters, and physical characteristic of the roadway. For a given
set of these parameters, a critical wind angle leading to maximum concen-
trations is also assumed. A discussion of these relationships is provided
in Sections II and III of this report. Thus, a highly specialized, mobile
monitoring program would be required to collect data for validation of
these guidelines. The purpose of this evaluation is to ensure that the
guidelines procedures are sufficiently conservative. They should detect
and verify all potential hot spots and, if they err, they should err
towards defining a location as a potential hot spot even though it might
be only marginally so. In this regard, the verification procedure concen-
tration estimates should generally always be at least as high as observed
values.
210
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Since the screening procedure is based totally on the verification pro-
cedure, there is no need to provide separate assessments of each; if it
is shown that the technical aspects of the verification process are
sound, then it would be valid to assume that the technical basis for the
screening techniques is also sound. In this connection, then, an assess-
ment was made only of the validity of the verification procedure. It
should be pointed out again that the technical basis for the entire pro-
cedure is the EPA Indirect Source Guidelines,16 which has been evaluated15
already. In this sense, it can be considered that the technical basis
for the Hot Spot Guidelines has also been assessed.
B. EVALUATION OF THE VERIFICATION PROCEDURE
In order to evaluate the adequacy of the verification procedure as a tool
for identifying the highest CO concentrations likely to occur at a lo-
cation, a comparative analysis was performed that considered actual mea-
sured air quality data and estimates derived using the hot spot guidelines,
Comparisons were made of the highest measured CO concentrations, and the
maximum value computed using the verification procedure for several sig-
nalized intersections and for several sections of roadway with uninter-
rupted flow. These are discussed below.
1. Case I: Verification at Signalized Intersections
The data required for the verification of six signalized intersections
were collected and compiled. The major constraint with regard to select-
ing study sites was the availability of representative, measured CO data.
The data for three of the sites analyzed were obtained from specific
short-term studies designed to evaluate local carbon monoxide levels. As
a result, the associated CO monitoring activities ranged from a few days
to a few weeks. The three remaining sites were selected because of the
existence of continuous monitoring programs at the sites and because of
the availability, at the minimum, of a full year's CO concentration data.
211
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Before presenting the verification results of the signalized intersections,
two caveats that affect the evaluation are highlighted. The first con-
cerns the location of the CO monitors. The verification procedure is
designed to predict CO concentrations at receptor sites where the maximum
projected level is most likely to occur. The locations where these
maximum concentrations occur depend on meteorological factors, such as
windspeed and direction, and traffic characteristics, such as queue
length. The actual air quality monitors, hpwever, are not located at the
point where, under the conditions assumed in the verification process, the
maximum concentrations occur. Therefore, the validation procedure should
not be expected to show close agreement between the maximum estimated and
measured concentrations; rather, the validation should show that in all
instances, the estimated values are higher than the measured concentrations.
The second caveat concerns the probability that the CO concentrations re-
corded are representative of the potential maximum concentrations. The
CO concentration data for three of the intersections were obtained from
rather short-term monitoring programs where sampling periods ranged from
a few days to a few weeks. It is highly unlikely that maximum CO levels
were recorded because of the shortness of the monitoring period and because
of seasonal implications of not necessarily monitoring during a "critical"
season (i.e., winter).
Table 18 presents the observed data along with the estimated values of
the verification procedures. At the three sites listed in Table 18 where
long-term monitoring data were available, the estimated values indicate
potential violations of the NAAQS. The observed concentrations verify the
fact that violations of the NAAQS did occur. In all three cases the
calculated value is greater than the maximum observed concentrations.
Again, monitor location plays a major role in these differences.
Of the other three locations, only two recorded violations in the NAAQS.
This is compared to results of the verification, which indicated maximum
values in excess of the NAAQS at all three locations. In all cases the
212
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Table 18. CASE I: RESULTS OF THE VERIFICATION PROCEDURE AT
SIGNALIZED INTERSECTIONS
Location
Buckingham St. at
Washington St.
Coif ax Ave. at
Colorado Blvd.
Moody St. at
Carter St.
Wisconsin Ave. at
Western Ave.
MacArthur Blvd. at
South Grand Ave.
Illinois Rte. 83 at
Twenty-Second St.
City
Hartford, Conn.
Denver, Colo.
Waltham, Mass.
Washington, D.C.
Springfield, 111.
Oak Brook, 111.
a
Monitor site
Trailer - (P)
at State Office Bldg.
National Jewish
Hospital - (P)
Trailer - (P)
Trailer - (T)
Site A - (T)
Site B - (T)
Site C - (T)
Site D - (T)
Station No. 13 - (T)
8-hour average CO concentration (ppm)
Estimated
35.1
55.8
24.3
51.7
27.6
22.7
18.6
26.1
Year
1974
1974
1975
1974
1975
1975
1975
1975
1975
Observed
21.2
19.7
19.9
13.9
5.5
2.9
2.6
2.3
8.2
Date
6/23/74
11/21/74
1/25/75
5/03/74
12/05/75
12/05/75
12/05/75
12/05/75
4/05/74
to
l->
OJ
(P) indicates permanent CO monitoring site; (T) indicates temporary CO monitoring site.
-------
verification results are considerably greater than the maximum observed
concentrations from the short-term monitoring programs, as might be
expected.
2. Case II: Verification at Uninterrupted Flow Locations
Table 19 presents the results of the application of the verification pro-
cedures at two major arterials in western New York State and one arterial
in Colorado. The maximum 8-hour average CO concentration observed at
either New York site during a 6-month air quality study, August 1975
through January 1976, was 6.2 ppm. These levels were recorded during
28 October 1975 for the Buffalo location and 30 December 1975 for the
Niagara Falls site. Applying the verification procedures results in es-
timated levels of 9.8 ppm and 5.7 ppm for Buffalo and Niagara Falls,
respectively. The Colorado site also shows hot spot potential with an
estimated maximum 8-hour average concentration of 12.5 ppm.
3. Case III: Comparison with Hourly Data at a Single Intersection
Hourly data were collected during a carbon monoxide and traffic monitoring
program conducted at the Oakbrook Shopping Center in Oakbrook, Illinois.25
A major intersection, Illinois Route 83 and Twenty-Second Street, south-
west of the center, was monitored as part of the shopping center study.
An evaluation of the hot spot verification guidelines presented in this
report has been conducted using the data collected at this signalized
intersection in Oakbrook. These data were also used to evaluate the
Indirect Source Guidelines.
Twenty sets of observed and estimated 1-hour average CO concentrations
were analyzed; these data represent 11 different hourly periods and four
different CO monitors. Table 20 summarizes the observed CO concentrations
along with the estimated concentrations of the verification procedures.
The estimated values are greater in all cases, as expected, because the
hot spot verification procedures are designed specifically to estimate
214
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Table 19. CASE II: RESULTS OF THE VERIFICATION PROCEDURE AT UNINTERRUPTED
FLOW LOCATIONS
Location
Sheridan Dr.
Rte. 324 west of
Ellicott Creek
Military Rd.
Rte. 265 at
LaSalle High School
West 57th Ave.
City
Buffalo, N.Y.
-
Niagara Falls, N.Y.
Arvada, Colo.
Monitor site
Trailer - (T)
Trailer - (T_
Trailer - (P)
8-hour average CO concentration * (ppm)
Estimated
9'. 8
5.7
12.5
Year
1975
1975
1975
Observed
6.2
6.2
11.6
Date
10/28/75
12/30/75
11/21/74
N>
f-»
Ul
-------
Table 20. OBSERVED VERSUS ESTIMATED 1 HOUR CO CONCENTRATIONS,
AT INTERSECTION OF ILLINOIS ROUTE 83 AND TWENTY-
SECOND STREET, OAKBROOK, ILLINOIS
Date
4/05/74
3/28/74
3/29/74
3/26/74
4/02/74
4/13/74
4/13/74
4/02/74
4/13/74
4/13/74
4/13/74
4/09/74
4/06/74
4/06/74
4/02/74
4/13/74
4/13/74
4/13/74
4/09/74
4/06/74
Hour
18
10
10
17
08
14
15
08
16
14
15
18
13
11
08
16
14
15
18
13
Receptor
162
162
162
162
14
14
14
15
15
15
15
15
15
15
13
13
13
13
13
13
CO concentration
1 hour average - (ppm)
Observed
7.3
5.6
7.3
7.0
7.3
3.0
3.0
3.9
3.9
5.6
5.6
8.2
4.7
4.7
7.3
4.7
3.9
4.7
4.7
4.7
Estimated
19.3
16.6
18.3
18.2
13.7
18.3
20.1
17.6
31.1
31.6
33.3
29.7
26.3
26.9
13.3
• 19.7
22.1
21.1
23.6
18.7
Estimated
with windspeed
correction
6.2
7.6
8.3
5.9
5.1
4.0
4.4
6.4
7.8
7.0
7.4
8.2
6.6
6.0
5.0
5.0
4.9
4.7
6.6
4.7
216
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the CO concentration potential under worst case conditions. If the esti-
mated values are corrected for windspeed (a windspeed of 1 m/sec is
assumed for Hot Spot Analysis), the agreement between measured and esti-
mated values improves considerably..
C. CONCLUSION
The hot spot screening and verification procedures have been evaluated on
the basis of comparisons with CO measurements. This section has demon-
strated the reasonableness of the guidelines as to their intended purpose,
which is to serve as a tool to facilitate an efficient review of poten-
tial CO hot spot conditions along existing roadway networks. Comparisons
with observed CO levels at seven signalized intersections and with ob-
served and estimated values for different times at a single intersection
illustrate that the guidelines identified all potential hot spot locations
analyzed.
217
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SECTION VIII
REFERENCES
1. Frye, F. F. Alternative Multimodal Passenger Transportation Systems,
Comparative Economic Analysis. Creighton Hamburg, Inc. For: Highway
Research Board, Washington, D.C. National Cooperative Highway Research
Program Report Number 146:68. 1973.
2. Benesh, F., and T. Midurski. Carbon Monoxide Hot Spot Guidelines
Volume II: Rationale. GCA/Technology Division, Bedford, Massachusetts.
Prepared for U.S. Environmental Protection Agency, Research Triangle
Park, N.C. EPA-450/3-78-034. August 1978.
3. Midurski, T. Carbon Monixlde Hot Spot Guidelines Volume III: Workbook.
GCA/Technology Division, Bedford, Massachusetts. Prepared for
U.S. Environmental Protection Agency, Research Triangle Park, N.C.
EPA-450/3-78-035. August 1978.
4. Benesh, F. Carbon Monoxide Hot Spot Guidelines Volume IV: Documentation
of Computer Programs to Generate Volume I Tables and Curves. GCA/Tech-
nology Division, Bedford, Massachusetts. Prepared for U.S. Environmental
Protection Agency, Research Triangle Park, N.C. EPA-450/3-78-036.
August 1978.
5. Benesh, F. Carbon Monixide Hot Spot Guidelines Volume V: Users Manual
for the Intersection-Midblock Model. GCA/Technology Division, Bedford,
Massachusetts. Prepared for U.S. Environmental Protection Agency,
Research Triangle Park, N.C. EPA-450/3-78-037. August 1978.
6. Benesh, F. Carbon Monoxide Hot Spot Guidelines Volume VI: Users Manual
for the Modified ESMAP Model. GCA/Technology Division, Bedford,
Massachusetts. Prepared for U.S. Environmental Protection Agency,
Research Triangle Park, N.C. EPA-450/3-78-040. August 1978.
7. Kunselman, P., et al. Automobile Exhaust Modal Analysis Model. U.S.
Environmental Protection Agency. Report No. EPA-460/3-74-005.
January 1974.
8. U.S. Environmental Protection Agency. Mobile Source Emissions Factors
for Low Altitude Areas. Final Document. EPA-400/9-78-086. March 1978.
218
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9. Highway Capacity Manual. Highway Research Board, National Academy
of Sciences, National Research Council, Washington, D.C, Special
Report No. 87. 1965.
10. Transportation and Traffic Engineering Handbook. Institute of
Traffic Engineers, Arlington, Virginia. 1976.
11. Robertson, J. E, The Impact of Vehicle Emissions on Air Quality at
Low Ambient Temperatures. Society of Automotive Engineers. -Paper
No. 741054. (Presented at the Automobile Engineering Meeting.
Toronto, Canada. October 1974.)
12. Guidelines for Air Quality Monitoring Network Design and Instrument
Siting (Revised). U.S. Environmental Protection Agency Report No.
OAQPS 1.2-012. Research Triangle Park, North Carolina 27711.
July 1975.
13. CO Siting. Supplement A to OAQPS 1.2-012. U.S. Environmental Protec-
tion Agency. Research Triangle Park, North Carolina 27711.
14. Ludwig, F. L., and J. H. S. Kealoha. Selecting Sites for Carbon
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219
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220
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TECHNICAL REPORT DATA .
(Please read Instmctions on the reverse before completing)
• REPORT
. . • —. vjrt l |^U
EPA-450/3-78-033
4. TITLE AND SUBTITLE
Carbon Monoxide Hot Spot Guidelines
Volume 1: Techniques
3. RECIPIENT'S ACCESSION-
5. REPORT DATE
August 1978
6. PERFORMING ORGANIZATION CODE
GCA-TR-78-32-G(l)
'. AUTHOR(S)
Theodore P. Midurski
8. PERFORMING ORGANIZATION REPORT NO.
9. PERFORMING ORGANIZATION NAME AND ADDRESS
GCA Corporation
GCA/Technology Division
Bedford, Massachusetts 01730
10. PROGRAM ELEMENT NO.
2AF643
11. CONTRACT/GRANT NO.
12. SPONSORING AGENCY NAME AND ADDRESS
Office of Air Quality Planning and Standards
Environmental Protection Agency
Research Triangle Park, N.C. 27711
13. TYPE OF REPORT AND PERIOD COVERED
14. SPONSORING AGENCY CODE
15. SUPPLEMENTARY NOTES
16. ABSTRACT
This report presents guidelines for the identification and evaluation of localized
violations of carbon monoxide air quality standards in the vicinity of streets and
highways. The guidelines are provided to facilitate the rapid and efficient review
of CO conditions along existing roadway networks, without the need for extensive
air quality monitoring, and are based upon the use of limited traffic data. Two
stages of review are provided for. Preliminary screening, performed with simple
nomographs included herein, simply identifies those locations with the potential to
violate CO standards; no quantitative estimate of CO concentrations results from
preliminary screening. Verification screening, using procedures and forms provided
herein, allows for consideration of additional site-specific conditions and provides
quantitative estimates of maximum CO concentrations. Both screening procedures are
performed manually and are based upon the EPA Indirect Source Review Guidelines.
Data collection procedures, computation techniques, and forms are recommended, and
examples are provided.
17.
KEY WORDS AND DOCUMENT ANALYSIS
DESCRIPTORS
Air Pollution
Atmosphere Contamination Control
Atmospheric Models
Carbon Monoxide
Exhaust Gases
Traffic Engineering
Transportation/Urban Planning
b.lDENTIFIERS/OPEN ENDED TERMS
Air Pollution Model
Automobile Exhaust
Highway Corridor Air
Quality Analysis
Relationships between
Traffic and Nearby
Air Quality
COS AT I Field/Group
13/13B
13. DISTRIBUTION STATEMENT
Release Unlimited
19. SECURITY CLASS (This Report)
UNCLASSIFIED
21. NO. OF PAGES
235
20. SECURITY CLASS (Thispage)
UNCLASSIFIED
22. PRICE
EPA Form 2220-1 (9-73)
221
*rU.S. GOVERNMENT PRINTING OFFICE: 1979-640-013 k 194REGION NO. 4
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