EPA-450/3-77-053
October 1977
CHARACTERIZATION
OF WASHINGTON, D.C.,
CARBON MONOXIDE
PROBLEM
U.S. ENVIRONMENTAL PROTECTION AGENCY
Office of Air and Waste Management
Office of Air Quality Planning and Standards
Research Triangle Park, North Carolina 27711
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EPA-450/3-77-053
CHARACTERIZATION
OF WASHINGTON, B.C.,
CARBON MONOXIDE PROBLEM
by
Theodore P. Midurski and Victor L. Corbin
GCA Corporation
GCA/Technology Division
Bedford, Massachusetts
Contract No. 68-02-1376
EPA Project Officer: Warren P. Freas
Prepared for
U.S. ENVIRONMENTAL PROTECTION AGENCY
Office of Air and Waste Management
Office of Air Quality Planning and Standards
Research Triangle Park, North Carolina 27711
October 1977
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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 - as supplies permit - from the Library
Services Office (MD-35), Environmental Protection Agency, Research Triangle Park, North Carolina
27711; or, for a fee, from the National Technical Information Service, 5285 Port Royal Road, Spring-
field, Virginia 22161.
This Final Report was furnished to the U.S. Environmental Protection Agency by the GCA Corpora-
tion, GCA/Technology Division, Bedford Massachusetts 01730, in fulfillment of Contract No. 68-02-
1376, Task Order No. 27. The opinions, findings, and conclusions expressed are those of the authors
and not necessarily those of the Environmental Protection Agency or of cooperating agencies.
Mention of company or product names is not to be considered as an endorsement by the Environ-
mental Protection Agency.
a
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FOREWORD
As Its first task under Contract No. 68-02-1376, Task Order No. 27, GCA/
Technology Division was to evaluate the adequacy of the data base in the
National Capitol AQCR for developing and testing techniques by which
changes in VMT and/or vehicle emissions could be related to changes in
ambient levels of oxidants and carbon monoxide. The data were to be
drawn from a baseline summertime period in either 1973 or 1974 and the
corresponding period in 1976. If the data base proved to be adequate,
work in developing these techniques was to begin. However, at the con-
clusion of this task it was jointly concluded by the EPA Project Officer
and GCA/Technology Division that fundamental Inadequacies in the existing
data bases would prevent carrying out the development and testing of such
techniques at this time. Under the revised CO phase of the program that
resulted from this decision, relationships between traffic, vehicle emis-
sions, and CO levels within the Washington, D.C. area were analyzed using
revised CO Hot Spot Guidelines techniques and supplementary computer simu-
lation models. The results of these analyses are presented in this report.
The revised oxidant phase of the work became a study to characterize the
Washington, D.C. oxidant problem using data collected during the summer
of 1976 by the local agencies, plus data collected under a number of spe-
cial programs sponsored by EPA. The results of this work are reported
separately.
iii
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CONTENTS
Page
Foreword ill
List of Figures vi
List of Tables viii
Acknowledgments x
Sections
I Introduction 1
II Carbon Monoxide Monitoring in Washington, D.C. 5
III Study Methodology 13
IV Study Procedure and Results 23
Appendixes
A Screening Nomographs 43
B Sample Screening Worksheets 52
C Washington, D.C. Hot Spot Screening Results 56
D Application of the Hot Spot Guidelines Techniques 86
E Sample Verification Worksheets 122
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LIST OF FIGURES
No. Page
1 Carbon Monoxide Monitoring Sites, Washington, D.C. 6
2 Cumulative Frequency Distribution of the Number of Days
With 8-hour Average CO Measurements Exceeding the NAAQS,
as a Function of the Concentrations Measured 10
3 Process Flow Diagram for the Screening of Carbon Monoxide
Hot Spots 16
4 Sample Section of the Worksheet Used in the Preliminary
Screening of Washington, D.C. 24
5 Grouped Frequency Distribution of Maximum 8-Hour Average
CO Concentrations for 29 Signalized Intersections in
Washington, D.C. 31
6 Grouped Frequency Distribution of Maximum 1-Hour Average
CO Concentrations for 29 Signalized Intersections in
Washington, D.C. 31
7 Location of Fairfax County Air Monitoring Station No. 4 35
8 Site Sketch - Wisconsin Avenue and Albemarle St., N.W.,
Intersection 36
A-l Critical Volumes at Signalized Intersections. Analysis of
a 2-Lane 2-Way Street in a Congested Area 44
A-2 Critical Volumes at Signalized Intersections. Analysis of
a 2-Lane 2-Way Street in a Noncongested Area 45
A-3 Critical Volumes at Signalized Intersections. Analysis of
a 3-Lane 2-Way Street in a Congested Area 46
A-4 Critical Volumes at Signalized Intersections. Analysis of
a 3-Lane 2-Way Street in a Noncongested Area 47
vi
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LIST OF FIGURES (continued)
No. Page
A-5 Critical Volumes at Signalized Intersections. Analysis of
a 4-Lane 2-Way Street in a Congested Area 48
A-6 Critical Volumes at Signalized Intersections. Analysis of
a 3-Lane 1-Way Street 49
A-7 Critical Volumes at Signalized Intersections. Analysis of
a 2-Lane 1-Way Street 50
A-8 Critical Volumes at Signalized Intersections. Analysis of
a 4-Lane 2-Way Street in a Noncongested Area 51
D-l Sample Worksheet Used in the Preliminary Screening of
Washington, D.C. 87
D-2 Screening Worksheet 89
D-3 Critical Volumes at Signalized Intersections. Analysis of
a 4-Lane 2-Way Street in a Noncongested Area 91
D-4 Completed Screening Worksheet 92
D-5 Site Sketch - Wisconsin Avenue at Albemarle Street, NW 93
D-6 Verification Worksheet - Wisconsin Avenue at Albemarle
Street, NW 97
D-7 CO Concentration Contribution From Excess Emissions on
Approach 1 as a Function of Number of Lanes and Queue
Length 102
D-8 Normalized CO Concentration Contribution From Excess Emis-
sions on Approach 1 107
D-9 Normalized CO Concentration Contributions From Excess Emis-
sions on Approaches 2, 3, and 4 108
D-10 Distance Correction Factor for Excess Emission Contribu-
tions at Intersections 109
D-ll Normalized CO Concentration Contributions From Free-Flow
Emissions on Each Lane of Roadways at Intersections 111
D-12 Distance Correction Factor for Free-Flow Emission Contribu-
tions at Intersection Locations 112
vii
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LIST OF TABLES
No. Page
1 Number of Days During Each Month of 1975 When the 8-Hour
and 1-Hour Standards for CO were Exceeded at Six Loca-
tions in Washington, D.C. 7
2 Eight-Hour Concentrations Exceeding the NAAQS by Month
and Day for Six Locations in Washington, D.C. 8
3 Summary of Preliminary Hot Spot Screening in
Washington, D.C. 25
4 Summary of Effort Expended in Performing Hot Spot Screen-
ing in Washington, D.C. 27
5 Results of the Hot Spot Verification Analysis at 29 Loca-
tions in Washington, D.C. 30
6 Summary of Effort Expended on Performing Hot Spot Verifica-
tion at 29 Locations in Washington, D.C. 33
7 Comparisons by Measured and Calculated CO Concentrations
at the Fairfax Station No. 4 38
8 Comparison of Measured and Calculated CO Concentrations
at the Tenley Friendship Library 39
9 Calculated 1-Hour CO Concentrations as a Function of Wind
Direction 40
D-l 10-Hour Turning Movement Count Summary - Wisconsin Avenue
at Albemarle Street, N.W. 95
D-2 Excess Emissions and Queue Lengths at Signalized Intersec-
tions as Functions of Maximum Lane Volume Per Hour on Main
Road (Horizontal Axis) and Maximum Lane Volume Per Hour on
Crossroad (Vertical Axis) 101
viii
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LIST OF TABLES (continued)
No. Page
D-3 Free Flow Emission Rate, Qf , in Grams Per Meter-Second as
a Function of Lane Volume and Vehicle Speed on Roadways
With Interrupted Flow (Intersections) 106
D-4 Light-Duty Vehicle Emission Correction Factor (Base Year
1975) for Catalyst-Equipped Vehicles (C „ ) and Non-
equipped Vehicles (CLDVnc) buvcac m
D-5 Light-Duty Truck Emission Correction Factor (Base Year
1975) for Catalyst-Equipped Trucks (GLDTcat) and Non-
equipped Trucks (CLDTnc) 115
D-6 Heavy-Duty Gasoline-Fueled Truck Emission Correction
Factor (Base Year 1975) (C) 115
D-7 Heavy-Duty Diesel Truck Emission Correction Factor (Base
Year 1975) (C) 115
D-8 Cold-Start Temperature Correction Factors for Catalyst
Equipped Light-Duty Vehicles (LDV) and Light-Duty Trucks
(LOT) 117
D-9 Cold-Start Temperature Correction Factor for LDV1 s and
LDT's Not Equipped With Catalyst (Ccs ) 118
ix
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ACKNOWLEDGMENTS
We would like to acknowledge the thoughtful assistance of David Barrett and
George Schewe of EPA's Source Receptor Analysis Branch, Monitoring and Data
Analysis Division during the course of this project. We would also like to
thank the District of Columbia Department of Transportation, Bureau of
Traffic Engineering and Operations, for their help in supplying us with
traffic data.
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SECTION I
INTRODUCTION
PROJECT OBJECTIVES
The primary objectives of the study being reported here include (1) pro-
viding insight as to the possible extent of carbon monoxide problems in
Washington, D.C., and (2) providing a demonstration of the use of a
three-part analytical procedure that was developed specifically for
assessing localized carbon monoxide problems; this procedure is described
in detail in a GCA/Technology Division report entitled Guidelines for
Identification and Evaluation of Localized CO Hot Spots. Volume 1; Tech-
niques and Workbook, hereafter referred to as the Hot Spot Guidelines.*
The nature of the study did not provide for a comprehensive analysis of
all aspects of carbon monoxide in the District; rather, a preliminary
investigation was made to determine whether or not there was a potential
problem at each signalized intersection in the city, and a more detailed
follow-up analysis was conducted at a number of individual intersections
where the preliminary investigation indicated that a potential problem
existed. Again, the intent of the project is, first, to provide a pre-
liminary analysis of the areal extent of carbon monoxide problems in
Washington, D.C. based on the screening procedures outlined in the Hot
Spot Guidelines, and second, to report on the experience gained in apply-
ing the Hot Spot Guidelines in a large urban area (i.e., Washington, D.C.)
* The Hot Spot Guidelines used in this study are a July, 1977 draft
incorporating emission estimates from Supplement 5 to AP-42. These
guidelines are presently being updated to Supplement 8 emission changes.
Under separate contract, the CO estimates herein for Washington, D.C.
will be redone. The final report of this subsequent study will super-
cede this report when completed.
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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.
Definite, deleterious health effects are associated with exposure of humans
to carbon monoxide, therefore it is for public health reasons that 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 for ambient con-
centrations 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, specified as National Ambient Air Quality
Standards (NAAQS), are that 1-hour average ambient concentrations 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/m3 (9 ppm) more than once
per year during nonoverlapping periods. 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.
Nonoverlapplng 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.
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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 SO . The highest concentrations are also most likely to
occur at locations with the highest emission rates. In this regard, the
locations of most interest for CO analyses are near points of heavy traf-
fic flow or traffic congestion.
A basic problem in the analysis of CO is to identify individual hot spots
(locations where the NAAQS is being violated). Until recently air qual-
ity monitoring data were considered to provide an adequate indication of
whether or not an area was in compliance with the NAAQS for CO. Numerous
studies, however, have indicated that CO problems are much more widespread
than is indicated by the existing monitoring networks. There are several
reasons for this apparent limitation in the ability of monitoring systems
to provide an adequate indication of the areal extent of CO problems.
First, monitoring networks to date have been rather limited with regard to
the actual number of sites measuring CO, owing primarily to the high cost
of equipping and operating a station. As an example, there were only five
CO monitors operated in the District during 1975. Second, a monitor gen-
erally provides a direct indication of CO concentrations within the im-
mediate vicinity of the monitor only, and it therefore may not detect lo-
calized, high concentrations of CO. Third, compromises generally are
required in selecting monitoring sites so that the actual locations where
measurements are being taken are not always the most desirable with regard
to Identifying the maximum concentrations to which the public may be exposed.
Alternatively, the trend has been to utilize various modeling procedures
to identify and analyze potential hot spots. One model designed specifically
for the task of identifying potential hot spot locations on an areawide
scale was recently developed by GCA/Technology Division and is described
in a report entitled Guidelines for Identification and Evaluation of
Localized Violations of Carbon Monoxide Standards, Volume I.1 The tech-
niques described therein provide the means for (1) conducting a relatively
simple first level analysis of an entire area to identify specific locations
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with hot spot potential; (2) conducting a more detailed second level anal-
ysis of those locations identified as having hot spot potential to provide
some dimension of the potential at each location; and (3) conducting a
rather detailed third level analysis of selected locations using computer
models to compute air quality based on traffic and meteorological parameters
specific to each location. The specific techniques used in the Hot Spot
Guidelines will be described in more detail later. These Hot Spot Guide-
lines were applied in the analysis of CO hot spots in Washington, D.C.;
the specific techniques used and the results of the analysis will be
described in detail in the following sections.
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SECTION II
CARBON MONOXIDE MONITORING IN WASHINGTON, B.C.
MEASURED CO DATA
The existence of carbon monoxide problems In Washington, D.C. has been
established through continuous air quality monitoring programs conducted
by the District of Columbia's Department of Environmental Services.
During 1975 and 1976, carbon monoxide concentrations were monitored at
six locations throughout the city; these locations are shown in Figure 1.
During 1975, violations of the national ambient air quality standard
(NAAQS) for 8-hour average concentrations of carbon monoxide occurred
at all six monitoring sites and the NAAQS for 1-hour average concentra-
tions was exceeded at two sites. Table 1 shows the number of days for
each month during 1975 that the 8-hour and 1-hour average concentrations
measured at the six monitoring sites exceeded the standards. The magni-
tude to which the 8-hour standard was exceeded is shown in Table 2.
The magnitude of the concentrations exceeding the NAAQS range from
3 3
10.4 mg/m (9.1 ppm) to 44.3 mg/m (38.9 ppm). The cumulative frequency
distribution for the data shown in Table 2 is presented in Figure 2.
This figure shows that the 50th percentile concentration is approximately
3
128 percent of the 8-hour standard or 13.1 mg/m (11.5 ppm).
Discussions with the Department of Environmental Services officials in-
dicated that the basic patterns of carbon monoxide concentrations recorded
during 1976 at the six monitoring sites were quite similar to those for
1975, with respect to both frequency and magnitude of violations of the
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TENLEY-FRIENDSHIP LIBRARY
MELVIN SHARPE SCHOOL
WEST END
LIBRARY
DC.
GENERAL
HOSPITAL
ST. ELIZABETH
HOSPITAL
Figure 1. Carbon monoxide monitoring sites, Washington, D.C.
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Table 1. NUMBER OF DAYS DURING EACH MONTH OF 1975 WHEN THE 8-HOUR AND 1-HOUR
STANDARDS FOR CO WERE EXCEEDED AT SIX LOCATIONS IN WASHINGTON D. C.
Location
Tenley-Frlendship
Melvin Sharpe
D.C. General
St. Elizabeth's
CAMP
West End Library
Standard
8-hour
1-hour
8-hour
1-hour
8-hour
1-hour
8-hour
1-hour
8-hour
1-hour
8-hour
1-hour
Number of days whose NAAQS was exceeded
Jan.
a
a
3
0
2
0
a
0
1
0
a
a
Feb.
2
0
6
1
2
0
a
0
1
0
a
a
Mar.
0
0
3
0
0
0
a
0
1
0
a
a
Apr.
1
0
1
0
0
0
a
0
0
0
2
0
May
2
0
2
0
2
0
a
0
0
0
0
0
Jun.
a
a
1
0
0
0
a
0
0
0
a
a
Jul.
0
0
3
0
a
a
a
0
0
0
a
a
Aug.
a
a
0
0
a
a
a
0
1
0
a
a
Sep.
a
a
0
0
0
0
a
0
a
a
a
a
Oct.
a
a
2
0
0
0
0
0
a
a
a
a
Nov.
7
0
5
0
2
0
3
0
a
a
3
0
Dec.
3
0
5
0
3
0
2
0
10
2
a
a
Incomplete data (fewer than 15 days reported).
Source: Reference 2.
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Table 2. EIGHT-HOUR CONCENTRATIONS EXCEEDING THE NAAQS BY
MONTH AND DAY FOR SIX LOCATIONS IN WASHINGTON, D.C.
Location
Tenley-Friendship
Melvin Sharpe
Date
5 Feb. 75
24 Feb. 75
28 Apr. 75
3 May 75
6 May 75
11 Nov. 75
12 Nov. 75
15 Nov. 75
17 Nov. 75
24 Nov. 75
25 Nov. 75
26 Nov. 75
1 Dec. 75
4 Dec. 75
26 Dec. 75
5 Jan. 75
7 Jan. 75
24 Jan. 75
14 Feb. 75
15 Feb. 75
17 Feb. 75
21 Feb. 75
22 Feb. 75
25 Feb. 75
6 Mar. 75
24 Mar. 75
25 Mar. 75
2 Apr. 75
17 May 75
29 May 75
28 Jun. 75
5 Jul. 75
30 Jul. 75
31 Jul. 75
7 Oct. 75
13 Oct. 75
16 Nov. 75
17 Nov. 75
18 Nov. 75
19 Nov. 75
25 Nov. 75
Maximum concentration
mg/m
12.7
15.7
12.1
11.7
12.9
10.7
16.3
12.1
11.2
14.3
15.2
14.0
10.8
10.4
12.3
10.4
19.8
15.8
12.9
18.9
13.2
10.6
30.7
15.8
21.7
14.4
12.8
11.2
11.9
10.8
10.6
10.9
11.8
10.6
10.9
12.9
14.9
14.9
17.4
17.7
12.1
(ppm)
(11.1)
(13.8)
(10.6)
(10.3)
(11.3)
(9.4)
(14.3)
(10.6)
(9.8)
(12.5)
(13.3)
(12.3)
(9.5)
(9.1)
(10.8)
(9.1)
(17.4)
(13.9)
(11.3)
(16.6)
(11.6)
(9.3)
(26.9)
(13.9)
(19.0)
(12.6)
(11.2)
(9.8)
(10.4)
(9.5)
(9.3)
(9.6)
(10.4)
(9.3)
(9.6)
(11.3)
(13.1)
(13.1)
(15.3)
(15.5)
(10.6)
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Table 2 (continued),
EIGHT-HOUR CONCENTRATIONS EXCEEDING THE NAAQS BY
MONTH AND DAY FOR SIX LOCATIONS IN WASHINGTON, D.C.
Location
Melvin Sharpe
(continued)
D.C. General
St. Elizabeth's
CAMP
Date
2 Dec.
5 Dec.
6 Dec.
12 Dec.
14 Dec.
7 Jan.
24 Jan.
15 Feb.
22 Feb.
16 May
17 May
17 Dec.
18 Dec.
5 Nov.
8 Nov.
24 Nov.
5 Dec.
17 Dec.
24 Jan.
15 Feb.
24 Mar.
26 Aug.
4 Dec.
5 Dec.
6 Dec.
8 Dec.
9 Dec.
11 Dec.
12 Dec.
13 Dec.
17 Dec.
31 Dec.
1 Apr.
2 Apr.
12 Nov.
13 Nov.
18 Nov.
75
75
75
75
75
75
75
75
75
75
75
75
75
75
75
75
75
75
75
75
75
75
75
75
75
75
75
75
75
75
75
75
75
75
75
75
75
Maximum concentration
3
mg/m
16.3
18.2
14.0
20.5
22.9
14.7
11.6
14.6
12.6
13.1
15.8
12.0
11.8
14.7
15.3
10.4
12.9
10.9
13.3
11.6
15.4
17.4
12.5
44.3
27.8
13.3
13.7
17.6
14.9
16.0
11.5
13.1
12.1
13.4
11.3
15.2
10.9
(ppm)
(14.3)
(16.0)
(12.3)
(18.0)
(20.1)
(12.9)
(10.2)
(12.8)
(11.1)
(11.5)
(13.9)
(10.5)
(10.4)
(12.9)
(13.4)
(9.1)
(11.3)
(9.6)
(11.7)
(10.2)
(13.5)
(15.3)
(11.0)
(38.9)
(24.4)
(11.7)
(12.0)
(15.4)
(13.1)
(14.0)
(10.1)
(11.5)
(10.6)
(11.8)
(9.9)
(13.3)
(9.6)
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73(100) r
g 72(92.3)
QC
£ 66(84.6)
<
|o 60(76.9)
«* 54(69.2)
i »- 48 (61.5)
«P
MX
|S 42(53.8)
— o (50.0)
<2 36(46.1)
30(38.5) h
S| 24(30.8)
OE in
g"
»» 18 (23.1)
ao
5°
K 12 (15.4)
w
5 6 (7.7) I-
0 (0.0)
100 110 120 130 140 ISO 160 170 180 190 200
MAXIMUM DAILY CONCENTRATION AS A PERCENT OF THE
8-HOUR NAAQS
Figure 2. Cumulative frequency distribution of the number of days with
8-hour average CO measurements exceeding the NAAQS, as a
function of the concentrations measured
10
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8-hour NAAQS. One exception, however, was that the number of days when
the 8-hour NAAQS was exceeded at the Melvin Sharpe School monitor de-
creased from 31 in 1975 to 6 in 1976. Also, the 1-hour NAAQS was not ex-
ceeded at the Melvin Sharpe School during 1976.
The data shown in Tables 1 and 2 indicate directly that the NAAQS for
carbon monoxide is being routinely exceeded at at least six locations
within the city. The implication, however, is that carbon monoxide
problems* may exist in many other areas of the city and these problems
may be much more severe than those indicated at the six monitoring sites.
This is based on (1) the generally accepted premise that the carbon mon-
oxide concentration occurring at any point is a function of emissions
strength, special separation of the emission source and the point of
interest, and a factor that reflects the dispersion characteristics (e.g.,
windspeed and direction, atmospheric stability, etc.) once the carbon mon-
oxide has been emitted to the ambient atmosphere; and (2) the actual loca-
tions of the six monitors with respect to both the overall street system
and the individual monitoring sites. The highest concentrations within a
city are expected to occur at locations that typically experience the
highest traffic volumes and levels of congestion. In Washington, D.C.,
these areas include the entire downtown, arterial corridors such as along
the Potomac River, Connecticut Avenue, Massachusetts Avenue, etc.; and in
the vicinity of very active generators such as National Airport. Monitor-
ing stations are not operated within these areas where the greatest
quantities of emission are likely to occur.
Also, a review of each monitoring site indicates that the sampling de-
vices are generally not located at the point where the highest concen-
trations (to which the public might be exposed) are likely to occur.
For instance, probes are often located on rooftops at heights of 10 to
15 meters or more above the sidewalk elevation. Also, probes are often
*Problems in this context meaning that ambient concentrations exceed
the NAAQS.
11
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set back from the sidewalk (or other reasonable receptor site) at dis-
tances of 10 to 15 meters. This implies that even at the individual
monitoring sites, maximum concentrations are not necessarily being
monitored.
A conclusion is that the apparent carbon monoxide problem in Washington,
D.C. cannot be characterized adequately using only data derived from
the air quality monitoring stations currently being operated. To ade-
quately delineate the problem citywide, an analysis is required to
characterize individual locations (i.e., hot spots) where street-level
concentrations of carbon monoxide may be exceeding the NAAQS on a
routine basis; the purpose of this report, then, is to demonstrate how
the Hot Spot Guidelines can be used to analyze this problem.
12
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SECTION III
STUDY METHODOLOGY
THE CO HOT SPOT GUIDELINES
Concept
In the analysis of carbon monoxide problems on an areawide scale there is
a need for a method other than monitoring that will identify specific
locations that are potential hot spots, and that will provide dimension
to this potential. Several computer models provide this capability;
however, computer models are generally expensive and complicated to run,
therefore it usually is inefficient to use this approach in the first
phases of an areawide analysis. The need for a somewhat less sophisticated
technique for performing initial studies of areawide CO problems resulted
in the development of the Hot Spot Guidelines (see Reference 1, Chapter 1).
The Hot Spot Guidelines provide the means for analyzing areawide CO problems
at three levels of detail. The first level, preliminary screening, pro-
vides a manual technique for identifying specific locations that have
hot spot potential, using very general data that are routinely available
at the local level. The second level of analysis provides an estimate of
the maximum concentration for a location, again using a manual technique,
but based on data that are much more site-specific than are used for the
preliminary screening. The third level involves computer modeling using
very detailed data that reflect specific traffic operating characteristics
and meteorological conditions; all three procedures are based largely on
Supplement No. 5 to AP-42. Each of these three levels of analysis is
discussed in the following paragraphs.
13
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CO Screening
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 emission 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). Added to the air quality effects of the emissions inten-
sity at any location is the background concentration which 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 characteristics will
vary most significantly among locations, while it can be assumed that the
other parameters are constant throughout an area. Therefore, the CO
screening process is based on an air quality-emissions intensity rela-
tionship where emissions intensity is the independent variable. Also,
emissions intensity is considered to be a function of two variables -
volume demand and facility capacity - 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 the hot spot screening procedures, a distinction is made between factors
that are site-specific and those that do not vary significantly from one
site to another. The highly site-specific elements, such as traffic
volume, speed, roadway capacity, and the distance seperating the roadway
and the assumed receptor location, are determined separately for each
location being analyzed and are treated as variables in the computations.
Other factors that do not change significantly within a region or state
are determined just once for each screening program. These include
14
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composite emission factors. Only expected worst-case meteorological con-
ditions are considered in conducting the screening analysis.
A series of nomographs is presented in the Hot Spot Guidelines that depict
the relationship between certain traffic factors and CO concentrations.
More specifically, the screening nomographs show "critical volumes" (that
is, the maximum traffic volume below which violations to the air quality
standards for CO are not expected) for numerous roadway configurations
within each of three general categories, including signalized intersections,
free-flowing sections of expressways and arterials, and STOP sign-controlled
intersections. The screening nomographs that were used in the analysis
are reproduced in Appendix A for reference.
The process outlined in the Hot Spot Guidelines for conducting an areawide
screening analysis begins with compiling the necessary traffic data. The
general types of data required include areawide volume data in the form
of a traffic flow or volume map, an inventory of signalized and STOP signs
controlled intersections, and a physical inventory of the street network
that identifies the number of lanes used and the type of operation (one-
way or two-way).
The Hot Spot Guidelines recommends that all signalized intersections within
the study area be analyzed for hot spot potential. Criteria are also
presented in the Hot Spot Guidelines for selecting tnidblock or free-flowing
locations, and STOP sign-controlled intersections for screening. The
reader is referred to the Hot Spot Guidelines for a detailed description
of the screening procedure; the procedure is outlined here, however, in
the flow diagram presented in Figure 3.
Hot Spot Verification
The verification process is a follow-up to the initial screening of an
area. The intent is to perform a more detailed evaluation of the hot
spot potential of a street section or intersection using a technique that
15
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COMPILE TRAFFIC, ROADWAY
Mt PLANNIN* OAT*
BEVCLOP/OITAIN TRAFFIC
now MM FOB iwr-Ts
O4TAIN CUT Of TRAFFIC SICNAL
LOCATION*. TOWNWIOE
OEVELOP/MTAIN OTHtR
CENCRAL ROADWAY DATA
PERFORM PRELIMINARY SCMEENIN*
OF EACH SIONALI2CO INTt K5CCT1ON
USE NOMOGRAPHS PROVwEOA
IX FI6URCS 2 THRU » J
USE FORM tj
( USE FOAM I ~)
USE NOMOGRAPHS PROVNICOX
O II J
IN FIGURES 10 ANO
FORM » )
(USE PORMlJ
PERFORM PRELIMINARY SCREENING
Of NONSIONALIZED INTERSECTIONS
USE NOMOGRAPHS PROVICCOA
IN FIGURES l5 THRU If J
Figure 3. Process flow diagram for the screening of
carbon monoxide hot spots
16
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allows input of parameters specific to that location rather than assumed
parameters. The initial screening process focuses on identifying poten-
tial hot spot locations anywhere within a city (thereby requiring a very
general approach); the verification process analyzes specific locations,
and a more detailed analysis of each location is feasible.
Conceptually, the technique involved is identical to that used for pre-
liminary screening. 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 par-
ticular set of meteorological conditions assumed, estimates of the re-
sulting air quality can be 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 esti-
mate of the highest expected 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 is
made using peak hour traffic data, temperatures typical of cold winter
days, and low wind speed (1 m/sec).
The verification process requires detailed data that are specific to the
particular location being analyzed. The types of data required include:
• Physical data including roadway alignment, number of lanes,
street widths, receptor location, etc.
• Traffic volume data including current peak-hour volume and
statistics from which projections can be made.
• Speed data.
• Receptor orientation.
• Vehicle classification data.
17
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Traffic signal data.
Estimates of the percentages of vehicles operating in the
hot or cold mode, and
Miscellaneous data regarding actions that will affect either
traffic or travel within the study area, or the emission
characteristics of the local vehicle fleet.
The reader is again referred to the Hot Spot Guidelines for a discussion
of the details concerning the data required for hot spot verification.
Hot spot verification Is conducted using the data elements mentioned above
and a series of curves and tables presented in the Hot Spot Guidelines.
The hot spot verification process will yield the expected worst-case car-
bon monoxide concentration in the vicinity of the roadway. The procedure
used to analyze each location can be summarized as follows:
1. Specify the site-specific traffic and roadway parameters.
2. Determine the optimum receptor placement.
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, this procedure consists of solving the following equation for
the expected peak carbon monoxide concentration for an 8-hour averaging
period:
X8 = C8 CE cd£ Qf + Cde Q£ *L 1 /« + XB (1)
18
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where xa = the estimated 8-hour average CO concentration at the
receptor;
CH " empirical conversion factor to change from a 1-hour
averaging time to an 8-hour averaging time;
Cp = 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);
Q- - 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;
Cdf • 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
e interrupted flow (m"1);
Cd = distance correction factor for the concentration con-
tribution from excess emissions from interrupted flow;
u = windspeed (m/sec); and
X0 - background concentration.
o
If the receptor is near a roadway with interrupted 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. Again, the Hot Spot
Guidelines provide detailed instructions for solving for X0 and also pro-
fs
vide tables and curves necessary to derive each term of the equation.
19
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Hot Spot Modeling
The third phase of hot spot analysis involves computer simulation of traffic
flow and air quality.
The model used for the simulation is referred to as the Intersection Mid-
block Model. The primary components of this model are the Modal Analysis
3 4
Model, a traffic flow model, and the HIWAY Model. In its present form,
the Intersection Midblock Model can accommodate multiple analyses of in-
dividual intersections or street sections. The model characterizes an in-
tersection in terms of the links approaching and leaving the intersection,
the type of intersection control (demand actuated, fixed time or two-way
stop), cycle time, green time, and capacity for each phase and approach.
The model also has the capability of treating free flow traffic conditions
and the variation of traffic volumes on an hourly basis. Link input param-
eters include coordinates of the starting and endpoint, number of lanes,
fraction of volume assigned to each lane, emission height, link width,
volume and cruise speed. For those links approaching an intersection the
deceleration into and the acceleration out of the intersection are also
specified for the calculation of acceleration/deceleration emissions in
the traffic queue. Receptor input data include the receptor coordinates
and height above ground, and for those receptors located along street can-
yons, the direction of the street from north, receptor street width, build-
ing height and side of the street on which the receptor is located.
As a first step in the calculation, emissions rates for deceleration (g/
vehicle), acceleration (g/vehicle), cruising (g/vehicle/sec) and idling
(g/vehicle/sec) are calculated for those links approaching intersections.
Cruise emission rates are then calculated for those links not approaching
an intersection. Intersection traffic calculations are then performed to
compute queue lengths, cycle times and queue delays which are then used to
determine line source excess emission rates (g/m/sec). For each physical
link approaching an intersection two links are constructed within the
model. The first is identical to the physical link with cruise emissions
20
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assigned to the entire length. The second link has the same terminus as
the physical links but has a length equal to the average queue length over
which the emissions are distributed. These emission rates together with
hourly meteorological data (windspeed, wind direction and atmospheric
stability) are used by either the HIWAY Model or Street Canyon Model to
calculate hourly carbon monoxide concentrations at selected receptor loca-
tions. The final determination as to whether the street canyon model will
be used for a given hour is determined by a criterion that involves at-
mospheric stability, wind speed, street width and building height.
Application of the Hot Spot Guidelines
The first phase of the hot spot analysis involved areawide screening. The
Hot Spot Guidelines indicate that the screening effort should include con-
sideration of signalized intersections, midblock arterial and expressway
locations, and selected nonsignalized intersections. For this project,
however, it was decided that the screening process would consider signalized
intersections only. This decision does not substantially reduce the ef-
fectiveness of the study in either demonstrating use of the Hot Spot Guide-
lines or delineating the potential CO problem in the District. Had the
analysis included midblock sections of arterials and nonsignalized inter-
sections, it is noted that all locations within each of these categories
would not have been analyzed anyway. The screening procedures specify
that only midblock sections and nonsignalized intersections that are clearly
not influenced by the presence of a signalized intersection either upstream
*
or downstream shall be analyzed.
The Hot Spot Guidelines suggest that signalized intersections can affect
traffic within a distance of about a half mile, therefore only midblock
sections of arterials and nonsignalized intersections that are greater than
a half-mile from a signalized intersection should be analyzed. Further,
the Guidelines state that the only expressway sections that need be con-
sidered are those where the daily volumes exceed 30,000 (for 4-lane high-
ways), 40,000 (for 6-lane highways), or 50,000 for (8-lane highways)
vehicles.
21
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This specification eliminated many locations from consideration owing to
the rather high density of signalized intersections within the District
(there are over 1,100 signalized intersections within the approximately
70 square mile area of the District).
The second phase of the analysis, involving hot spot verification, was
also limited. Ordinarily, verification would be conducted at every loca-
tion identified in the preliminary screening as either having a hot spot
potential or being a complex intersection or special case. For the pur-
poses of this study, verification was performed at 29 intersections. The
two primary criteria used in selecting locations for verification were
the desire to analyze several functionally-different types of locations in
several types of setting and the need to maximize use of existing data.
The third phase of the analysis involved comparing the results of the
modeling phase with monitor data. This was accomplished by modeling air
quality at two monitoring sites and comparing the results with measured
hourly concentrations for several days during 1974, 1975, and 1976.
The final phase of the study involved comparing long-term monitoring data
with the results of the verification analysis. The primary constraint here
was the lack of monitoring sites where the actual monitor was situated in
a manner that approximated the assumed receptor location. In fact, only
one monitoring site provided a reasonable approximation of the assumed
receptor location, and this phase of the study involved the analysis of
that location.
Summary
As the study methodology implies, the focus of the project was to provide
a demonstration of the Hot Spot Guidelines as well as a first level anal-
ysis of potential CO problems in Washington, D.C. In this connection, it
should not be inferred that the study provided a comprehensive analysis of
CO problems in the District. The conduct and results of the study are de-
scribed in the following section.
Complex intersections are those with unusual geometry or signal cycles that
include more than two phases; special cases are locations where the signal
is operated manually or only during certain hours of the days.
22
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SECTION IV
STUDY PROCEDURE AND RESULTS
INTRODUCTION
As indicated in the previous section, the study methodology consisted of
four seperate phases, viz:
• Hot spot screening
• Hot spot verification
• Hot spot modeling
• Comparison of verification procedure results
with monitoring data
The purpose of this section is to describe the procedures and data used
in conducting each of the four phases of the study as well as to present
the results of each.
HOT SPOT SCREENING
Screening Procedure
The hot spot screening process involved the analysis of all signalized
intersections in the District. The first step in the process was to com-
pile a data base. In this connection, arrangements were made with the
District of Columbia Department of Transportation, Bureau of Traffic En-
gineering and Operations to obtain several necessary data elements includ-
ing (1) an areawide traffic volume map depicting 1975 average daily traf-
fic (ADT) volumes for most streets in the District, (2) a street log that
included block-by-block pavement widths for all streets in the District,
23
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and (3) a traffic signal locations map. These data were assembled and
reviewed, and any apparent inconsistencies, omissions, or other inadequa-
cies were recorded so that appropriate action (i.e., field reconnaissance
or additional data requests) could be taken to complete the data base.
A total of 1131 signalized intersections were identified from the data.
These locations were analyzed for hot spot potential using the preliminary
screening procedures described in the Hot Spot Guidelines. The analysis
year represented in the screening is 1977. The traffic volume data,
which reflected 1975 ADT, were adjusted to more closely reflect 1977 con-
ditions by increasing link volumes by 8 percent and rounding to the nearest
thousand.
The appropriate data for each intersection were entered on a worksheet,
a portion of which is presented in Figure 4 below.
Tmtt II Co^uMd mtmml l«»i •>.
tut III Camflf* IturMttim or Sp*cUl Cmfml !»•: Ho; If j»i, mtn laettlam on Initial lcn«lp(
liM»rr SkMt mat proeMd to «•« latnMctlo*; If no, prccul >lcb Part If.
PMC IV Aa*ly«« «ae)i Us ••pttratvly em ck* for*. b«lev.
L«f voimr mmmlymiM
•
DMl|»tl»
^x^
MJuatW
an
(1977-78)
X
1
Coofltw-
mtlmm
X
CrM*~*tr««t mmtm
8tr««tt LMI 8tr««t: l*ti
Uivmtmt
at
(M77-7»)
i
Coo(l(iir-
•tlo*
f_
Pl«ur./
eurv* umrni
ft
tot >pot
Indicated
Strtctt LMI
Ujmmtmd
at
(1*77-71)
I
Confltiir-
• ClOB
1
Tlfur*/
eiirv* tnmm
k
tot mr*t
tmilmmtmt
8tr««t: L«t:
Figure 4. Sample section of the worksheet used in the preliminary
screening of Washington, D.C.
24
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The actual determination of whether or not a location had hot spot poten-
tial was based on the screening curves presented in the Hot Spot Guidelines
(also, see Appendix A). Throughout this phase of the study each inter-
section was analyzed only to the point where it was shown that hot spot
potential did or did not exist; in other words, if the first approach
analyzed displayed hot spot potential, then no additional approaches were
analyzed.
Several examples of completed worksheets are provided in Appendix B, and
a detailed description of the actual application of the procedure is pro-
vided in Appendix D.
Screening Results
The results of the screening analysis are most meaningfully portrayed in
summary form as presented in Table 3.
Table 3. SUMMARY OF PRELIMINARY HOT SPOT SCREENING IN WASHINGTON, D.C.
Status
• Identified as having hot spot potential
• Determined not to have hot spot potential
• Not analyzed-complex intersection or
special case
• Not analyzed-insufficient data
Total number of locations
Number of
locations
660
103
270
98
1,131
Obviously, the analysis indicates that a rather extensive potential exists
for hot spot problems in the District. This conclusion is based not only
on the 660 locations specifically identified as having hot spot potential,
but also on the observation that many of the intersections included in
the category of complex intersections are located along very high volume
25
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arterials and the combination of high volumes and complex geometry un-
doubtedly results in hot spot potential. Similarly, the 98 intersections
where sufficient data were not available are located along relatively
lightly traveled streets and therefore many of these probably do not have
hot spot potential.
To summarize the results of the screening analysis, it appears that the
areal extent of the potential hot spot problem in Washington, D.C. is
quite substantial. The locations identified as having hot spot poten-
tial are not confined to any particular section (e.g., the downtown area,
around the tourist attractions, etc.) of the city. The single factor
that contributes most significantly to hot spot potential is high volume
demand; volume demand is uniformly high throughout the entire District.
A listing of all locations analyzed and the status regarding hot spot
potential is included in Appendix C.
Level of Effort Expended
The screening effort involved several individual tasks of both a technical
and administrative nature. The technical tasks focused on data analysis
and the actual screening, while the administrative functions included
items such as developing work plans and supervising and checking the
technical work performed. It would be expected that these types of tasks
would be required regardless of the size of the area being screened or
the depth of analysis. Specific tasks and the estimated effort expended
for each are shown in Table 4.
Again, the tasks shown in Table 4 will generally be required for any area-
wide screening analysis that utilizes the Hot Spot Guidelines. The actual
effort can be expected to vary considerably, however, from city to city.
Two factors are particularly important concerning the actual effort that
would be required to conduct an areawide screening exercise - these include
(1) the size of the area, or more specifically, the number of locations
26
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that will be considered, and (2) the quality and quantity of available
data. Fortunately, a very substantial quantity of high quality, relevant
data was available from the District Department of Transportation, Bureau
of Traffic Engineering and Operations, therefore relatively little effort
was required to compile an adequate data base.
Table 4. SUMMARY OF EFFORT EXPENDED
IN WASHINGTON, D.C.
IN PERFORMING HOT SPOT SCREENING
Task
Type
Estimated man-hours
expended
• Develop work plan
• Identify and contact data sources
• Review and assemble data
• Conduct screening exercise
• Summarize results of screening
exercise
• Supervise and check
technical effort
Total estimated man-hours
Administrative
and technical
Administrative,
some technical
Technical
Technical
Technical
Administrative
16
8
16
120
24
16
200
It is of interest to note that the actual analysis time for each inter-
section was about 5 minutes; this includes the time required to locate the
intersection on the traffic volume map, identify the appropriate volumes,
adjust the volumes, enter the data on the worksheet, determine the setting
(congested or noncongested area) and types of approaches (e.g., 4-lane,
2-way), assess whether or not the intersection should be considered a
complex intersection, and finally select and use the appropriate nomograph.
Also, it is of interest to note that most of the technical work can be
accomplished by individuals who have only limited exposure to traffic
engineering practice; the Guidelines were, in fact, designed for use by
subprofessional skill levels.
27
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HOT SPOT VERIFICATION
Verification Procedure
Ordinarily, the verification procedure would be applied to all locations
identified in the screening process as either having hot spot potential
or being complex intersections or special cases. Had this procedure
been followed here, the verification process would have been applied to
about 950 separate intersections — this clearly was beyond the scope of
this project. Instead, it was established that the analysis of 29 loca-
tions would provide a reasonably good demonstration of the procedure and
at the same time be within the scope of the project.
As indicated previously, the criteria used in selecting study locations
focused on the desire to (1) consider several functionally different
types of locations situated in different urban settings, and (2) maximize
the use of existing data. In this connection liaison was again established
with the District Department of Transportation, Bureau of Traffic Engin-
eering and Operations to identify locations where current data would be
available for use in the analysis. Owing to the rather extensive data
base maintained by the Bureau, it was possible to identify at least 29
locations that met both criteria.
For each location, the Bureau provided the following data elements:
1. 10-hour intersection turning movement counts including
pedestrian crossing data, taken during 1975 and 1976.
2. Traffic signal data including phasing and timing diagrams.
3. Intersection layout drawing showing lane widths and use
(one-way or two-way) and intersection geometry.
Field reconnaissance was required, however, to identify any unusual fea-
tures associated with each location that would not be apparent from the
abovementioned data elements. Also, field reconnaissance was required
to identify "reasonable receptor" locations within each intersection as well.
28
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Data were not available regarding the vehicle-type mix specific to each
location; instead, a standard vehicle mix was assumed that included
88 percent light-duty vehicles, 8 percent light-duty trucks, 3 percent
heavy-duty, gasoline-powered vehicles, and 1 percent heavy-duty, diesel-
powered vehicles. Further, it was assumed that 5 percent of the vehicles
were operating in the cold mode, and 10 percent in the hot transient
mode. Correction factors for cold mode and hot transient vehicles were
computed for both catalyst- and noncatalyst-equipped light-duty vehicles
and light-duty trucks, using an assumed ambient temperature of 30 F.
The data described above were entered on the standard worksheet provided
in the Hot Spot Guidelines and the maximum 8-hour average CO concentration
computed using the procedures, curves, and tables also presented in the
Guidelines. Appendix D provides a detailed description of the application
of the verification procedure in the analysis of CO concentrations; Appen-
dix E provides examples of completed verification worksheets for several
intersections.
Results of the Verification Analysis
The verification process serves to quantify the hot spot potential at a
location in terms of an estimated "worst case" concentration. These worst-
case concentrations computed for the 29 study locations are presented in
Table 5, below. As can be seen, all 29 locations appear to have the
potential to exceed the 8-hour NAAQS of 10 mg/nr (9.0 ppm) while 12 appar-
ently have the potential to exceed the 1-hour standard of 40 mg/m3
(35.0 ppm).
The relative hot spot potential among the 29 locations can be seen in
Figure 5 and Figure 6, which provide the grouped frequency distribution
of the maximum 8-hour and maximum 1-hour average concentrations,
respectively.
29
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Table 5. RESULTS OF THE HOT SPOT VERIFICATION ANALYSIS AT
29 LOCATIONS IN WASHINGTON, D.C.
Location
1. Alabama Avenue <" Branch St.
2. E Street @ 7th Street NW
3. E Street 9 4th Street NW
4. G Street 9 14th Street NW
5. L Street 9 20th Street NW
6. Independence Avrnue 8
6th Si -ret SW
7. M.L. King '«nu,' » Goodhope
Ro»d SE
8. M Struct 9 WMti'hurat Parkway
SW
9. L Street 9 9th street NW
10. Rhode Ix land Av.nue @ South
Dakota Avenue NE
11. Monroe Street 9 12th Street NE
12. G Street 9 10th Street NW
13. Wleconeln Avenue @ Harrison
Street NW
14. Georgia Avenue (? V Street NW
15. Massachusetts Avenue (?
Wisconsin Avenue NW
16. 16th Street 9 Kalmit Road NW
17. Pennsylvania Avenue 9 13th
Street NW
18. F Street f 13th Street NW
19. Nebraska Avenue 9 Reno Road NW
20. Wisconsin Avenue 9 N Street NW
21. Nebraska Avemu- (' Van Ness
Street NW
22. Rhode- Island Avonue 9 Florida
Avfnur NR
23. K Street (J Connecticut Avenue
NW
24. L Street 9 6th Street
2}. Pennsylvania Avenue 9 3rd
Strcut NW
26. Wisconsin Avenue 9 P Street NW
27. Florida Avenue 9 16th Street NW
28. Maryland Avenue 3 3rd Street SW
29. Wisconsin Avenue t Albeaarle
StrtTt NW
Preliminary screening results
Has hot spot
potential
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
Complex Inter.
or special case
X
X
X
X
Insufficient
data
X
Maxl»u» expected
concentration, *
B>»/»3
1-hour
average
50.1
26.6
20.2
46.7
27.4
38.0
34.7
43,8
37.4
49.7
25.7
20.6
30.1
21.7
52.3
57.5
63.2
32.2
47.2
21.1
38.6
61.1
54.1
36.9
63.4
27.9
29.1
49.8
36.8
•-hour
average
35.1
18.6
14.2
32.7
19.1
26. t
24.)
30.7
26.1
34.8
18.0
14.4
21. a
13.2
36. t
40.2
44.3
22.5
33.1
14.8
27.0
42.8
37.9
25.8
44.4
19.6
20.4
34.8
23.7
'Concentrations indicated represent the »axl«u« expected at the eloeeet reasonable receptor
(usually the renter Una of an adjacent sidewalk).
30
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o 10 is 10 ae >o SB 40 46 eo
COMPUTED MAXIMUM •-•». AVKMACE CONCINTMATIOM(«*«/"I3I
Figure 5. Grouped frequency distribution of maximum 8-hour average CO
concentrations for 29 signalized intersections in
Washington, D.C.
0 i III t4 It 40 *• »« •« T|
COM^WttO MAXIMUM I-kr. AVtMWI COMCfWTHATIOII (•"«/»»)
Figure 6. Grouped frequency distribution of maximum 1-hour average
CO concentrations for 29 signalized intersections in
Washington, D.C.
31
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Care must be exercised in interpreting the results of the verification
analysis. It is emphasized that the computations are based on worst case
meteorological conditions, therefore the concentrations derived from the
analysis are obviously higher than normal. An important aspect of assessing
air quality problems concerns the frequency distribution of concentrations
in excess of the various standards. In fact, the relative severity of an
air quality problem cannot accurately be defined without both an indica-
tion of the frequency that the appropriate standard is exceeded, and a
quantitative measure of the magnitude of the concentrations above the
standard.
Several techniques have been suggested for investigating the probable
frequency distribution for locations where long-term monitoring has not
been used. Generally, these techniques include the analysis of macro-
and micro-meteorological patterns, which provide the basis for describing
the air quality distributions. These techniques are relatively complicated
and are generally beyond the scope of the hot spot verification process —
it is important to emphasize that the screening and verification processes
concern hot spot potential. A discussion of the frequency distribution
of the highest concentrations expected at any location is presented in
the Hot Spot Guidelines.
Level of Effort
The verification analysis involved both technical and administrative tasks
of the type that would be expected for any study using the procedure.
Table 6 provides a summary of the general categories of tasks and the
amount of effort expended on each.
It is again important to note that the effort did not include extensive
field data collection, owing to the availability of sufficient data from
the District Department of Transportation. Had data not been available,
it is quite likely that at least an additional 100 man-hours would have
been required to perform field studies.
32
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Table 6. SUMMARY OF EFFORT EXPENDED ON PERFORMING HOT SPOT VERIFICATION
AT 29 LOCATIONS IN WASHINGTON, D.C.
Task
• Develop work plan
• Obtain data (Including field
reconnaissance)
• Review and assemble data
• Conduct verification exercise
• Summarize results of verifica-
tion exercise
• Supervise technical effort
Total estimated man-hours
Type
Admini s t rat 1 ve
and technical
Administrative
and technical
Technical
Technical
Technical
Administrative
Estimated man-hours
expended
16
64
16
40
8
16
160
While the procedures for hot spot verification are still somewhat general,
the level of expertise required in traffic engineering is substantially
greater than that required for screening. Much of the technical work can
be accomplished by a technician with some exposure to various traffic
engineering concepts and principles, but the nature of the process suggests
that it would be appropriate for a professional-level traffic or trans-
portation engineer to have overall technical and administrative respons-
ibility for the analysis.
HOT SPOT MODELING
Site Selection
Two locations with CO monitors were used to test the Intersection Midblock
Model. Although neither monitor was suitably located to coincide with the
33
-------
receptor location assumed in the Guidelines, the necessary input data
were available to permit a demonstration of the model at each site.
The first site used is in Fairfax County, Virginia, near the intersection
of Lewinsville Road and Route 123. CO is measured near the roof of the
monitoring trailer and windspeed and direction are also observed at the
site. Traffic data and the accompanying meteorological and CO data were
made available to GCA/Technology Division from a study conducted by
Engineering-Science for the County of Fairfax.6 Calculations were carried
out for two 1-hour periods, selected to correspond with the morning and
afternoon peaks in traffic volume, on 20 days during 1974 and 1975. Fig-
ure 7 shows the location of the monitoring site and the principal nearby
intersection used in the model calculations.
The second demonstration of the model was carried out using the Tenley
Friendship Library site near the intersection of Wisconsin Avenue and
Albemarle Street (see Figure 8). Initial calculations at this site showed
the type of problems likely to be encountered when attempting to validate
an intersection model using data from an existing monitor. In this case,
the monitor is located to the rear of the roof of a 13-meter high building.
Using a height of 13 meters in the model results in zero concentration pre-
dictions because, for the stable or neutral atmospheric conditions assumed,
all of the CO generated near the intersection passes below the monitor.
A more realistic, though crude, assumption for this configuration of in-
tersection and building is to assume that the air is forced up and over
the structure, and that the monitor is therefore effectively at source
height. With this assumption, hourly measured and calculated CO concen-
trations for this site were compared for 2 consecutive days in June when the
wind direction during the morning rush hour was northeasterly. Also, the
sensitivity of the calculated concentrations to wind direction was tested
*
The assumed receptor location is at the point where the maximum concentra-
tion is most likely to occur at a height of approximately 2 meters and a-
long a line generally parallel to and offset from the edge of the roadway.
34
-------
FAIRFAX COUNTY AIR MONITORING
STATION NO. 4
Figure 7. Location of Fairfax County Air Monitoring Station No. A
-------
MONITOR
,000
D
D
D
\
D
D
•
D
D
APPROX
D
D
70'
C UOMITOR
| APPROX.
1
ELEVATION A-A
(NO SCALE)
WISCONSIN
AVENUE
CLOSED FOR CONSTRUCTION
Figure 8. Site sketch - Wisconsin Avenue and Albemarle St., N.W.,
intersection
36
-------
since the actual wind direction and windspeed at the intersection could
well vary significantly from that interpolated from the 3-hourly observa-
tions at National Airport, and used in the model.
Results
In Table 7 the measured and calculated 1-hour CO concentrations at the
Fairfax, Virginia site are presented along with the locally measured wind
data, and the stability class for each hourly calculation. Examination of
Table 7 shows that the model results, being based on the traffic flow at
the intersection southwest of the monitor, are quite sensitive to wind
direction. The contribution of the intersection to the monitor site be-
comes insignificant as the wind becomes westerly, while the observed
values on two of these occasions equaled 4.6 mg/m3 (4 ppm). During both
these periods the windspeed was very light, and the wind direction probably
was quite variable. Thus part of the 4.6 mg/m3 (4 ppm) could have been con-
tributed from the intersection as well as from other neighboring sources.
Generally, the intersection model did not account for all of the observed
CO, although at 0700 the agreement is close in four of the 16 cases, and the
calculated value exceeds the observed in two cases. The average excess of
observed over predicted at 0700 is 2.5 mg/m3 (2.2 ppm), which is not an un-
reasonable background level for this time of day. At 1600, calculated con-
centrations are less than observed in all but one of the 19 cases, and the
average difference between observed and predicted concentration is 1.4 mg/m3
(1.2 ppm). In a version of the Intersection Midblock Model currently under
development, background estimates, if desired, will be provided on an hourly
basis by use of the APRAC-la Model. The addition of background estimates
should result in closer agreement between calculated and observed values.
The measured and calculated 1-hour CO concentrations at the Tenley Friend-
ship Library, the wind conditions as interpolated from the National Air-
port 3-hourly data, and the stability for the two 8-hour periods tested are
given in Table 8. During both periods, the use of the model without pro-
vision for background levels results in serious underprediction. The
37
-------
Table 7. COMPARISONS BY MEASURED AND CALCULATED
CO CONCENTRATIONS AT THE FAIRFAX
STATION NO. 4
Date
7/3/74
7/14/74
7/15/74
7/18/74
8/17/74
8/29/74
9/12/74
9/13/74
10/17/74
10/22/74
11/4/74
11/18/74
12/17/74
12/19/74
5/6/75
3/15/75
4/24/75
6/6/75
6/4/75
6/12/75
6/23/75
Start
hour
07
16
07
16
07
16
07
16
07
16
07
16
07
16
07
16
07
16
07
16
07
16
07
16
07
16
07
16
07
16
07
16
07
16
07
16
07
16
07
16
07
1*.
Wiad
direction,
degree
240
260
210
210
250
190
195
240
200
180
180
270
150
250
210
180
230
180
210
225
195
210
270
165
225
195
270
210
285
210
190
200
260
200
260
180
200
Wind-
epeed,
m/B
1.1
2.1
3.6
2.9
1.1
2.2
3.6
1.6
3.8
1.3
2.2
0.7
2.2
1.1
2.2
0.4
1.6
1.3
4.9
0.5
2.7
0.9
1.1
1.3
2.0
1.3
3.8
0.9
4.0
4.7
2.7
2.0
2.7
2.0
2.7
3.4
2.9
Stability
class
3
2
2
4
2
4
3
3
2
4
3
3
3
3
3
3
3
3
4
3
4
3
4
4
4
3
3
3
4
4
4
4
2
4
2
4
2
CO
observed ,
mg/m3
6.7
0.7
M-
0.0
1.4
1.4
1.4
0.0
M
2.0
M
4.6
4.0
2.0
4.6
2.6
4.6
2.6
13.2
3.3
5.3
4.6
4.6
5.3
13.2
1.4
2.6
4.0
6.7
0.0
10.6
0.7
1.4
3.3
2.4
0.7
2.6
0.7
1.4
M
M
1.4
CO
calculated ,
mg/mj
0.4
M
0,6
2.1
0.1
1.2
0.8
M
0.3
M
0.6
1.3
0.9
0.5
0.2
1.9
6.7
0.8
1.1
1.2
7.2
2.9
8.2
2.4
1.5
3.3
5.2
1.4
1.5
2.3
2.3
0.5
M
M
1.0
*M reflect* missing date.
38
-------
Table 8. COMPARISON OF MEASURED AND CALCULATED
CO CONCENTRATIONS AT THE TENLEY FRIEND-
SHIP LIBRARY
Date
6/3/76
Thursday
6/4/76
Friday
Start
hour
4
5
6
7
8
9
10
11
4
5
6
7
8
9
10
11
Wind
direction,
degree
30
33
36
40
43
46
50
53
40
36
33
30
36
43
50
63
Wind-
speed,
m/sec
4.3
4.5
4.7
4.9
5.4
6.0
6.5
6.3
3.2
3.8
4.3
4.9
5.0
5.2
5.4
5.4
Stability
class
6
4
4
4
3
3
3
3
6
4
4
3
3
3
3
3
CO
observed,
mg/m3
4.6
5.7
6.9
8.0
9.2
10.3
1.1
1.1
6.9
6.9
8.0
9.2
8.0
6.9
6.9
5.7
CO
calculated,
mg/m3
1.5
1.0
1.0
2.0
1.3
0.6
0.3
0.3
1.0
1.0
1.4
2.5
1.8
0.8
0.4
0.6
39
-------
probability that the background levels were high on these two mornings is
supported by the observations during the 0300 to 0400 period when the vol-
ume of traffic through the intersection is very low. Concentrations re-
ported for this hour on the third and fourth, respectively, were 3.5 and
o
5.7 mg/m . The sensitivity of predicted concentrations to wind direction '
is illustrated in Table 9. The assumptions used in making these calcula-
tions were: windspeed, 1 meter per second; stability, class 4; mixing
height, 5000 meters; traffic volume, 9 percent of ADT; and receptor height,
1 meter.
Table 9. CALCULATED 1-HOUR CO CONCENTRATIONS AS A FUNCTION OF
WIND DIRECTION
Wind direction,
degree
0
5
10
15
20
25
30
35
40
45
Concent rat ion ,
mg/m3
13.8
17.0
18.2
17.4
15.6
13.3
10.8
8.5
6.4
4.9
Wind direction,
degree
50
55
60
65
70
75
80
85
90
Concentration,
mg/m3
3.9
3.6
3.9
4.7
5.6
6.3
6.7
7.0
7.5
VERIFICATION RESULTS VERSUS MONITORING DATA
Procedure
An ideal test of the verification process would be to compare the results
obtained from it to a set of measured data, assuming that both the mea-
sured data and the verification results reflect conditions at a common
point in time and space. Unfortunately, a valid comparison of this type
is virtually impossible if existing monitoring locations are used as the
source of the measured data. The root of the problem is that the moni-
toring stations and the verification procedure generally are not consider-
ing the same point in space since the verification process assumes that
the receptor is located at the point of maximum concentration.
40
-------
Notwithstanding the above-mentioned problems, comparisons were made be-
tween the maximum CO concentration computed for the intersection of
Wisconsin Avenue at Albemarle Street NW, and data summaries from the per-
manent monitoring station located near that intersection. A sketch of
the intersection showing the orientation of the monitor with respect to
the roadways was presented previously as Figure 8. The intent of this
comparison was strictly to determine whether or not the verification
procedure would provide a conservative estimate of worst case air
quality.
Data from the monitoring station were obtained for much of 1975 from the
District of Columbia Department of Environmental Services. These data
indicated that the maximum 1-hour and 8-hour average concentrations at
the site were 34.5 mg/m3 (30.0 ppm) and 16.4 mg/m3 (14.3 ppm), respec-
tively, while the verification process computed maximum 1-hour and 8-hour
average concentrations of 39.0 mg/m3 (33.9 ppm) and 27.4 mg/m3 (23.8 ppm),
respectively.
It is very difficult to draw any conclusions regarding the predicted
versus the measured maximum concentration. Perhaps the only conclusion
that would be appropriate is that monitoring data does not necessarily
reflect the highest concentrations that can occur within an intersection
under the most severe (with respect to air pollution) meteorological
conditions.
Occurring on 30 November and 13 November, respectively, at the Tenley-
Friendship Library site.
41
-------
REFERENCES
1. Guidelines for Identification and Evaluation of Localized Violations
of Carbon Monoxide Standards. GCA/Technology Division, Bedford,
Massachusetts. Prepared for U.S. Environmental Protection Agency,
Research Triangle Park, N.C. Contract No. 68-02-1376.
2. Annual Report on the Quality of the Air in Washington, D.C. 1975.
Government of the District of Columbia, Department of Environmental
Services, Bureau of Air and Water Quality, Air Monitoring Division.
3. Kunselman, P., et al. Automobile Exhaust Emission Modal Analysis
Model. U.S. Environmental Protection Agency. Report No. EPA-460/
3-74-005. January 1974.
4. Zimmerman, J.R. and R.S. Thompson. User's Guide for HIWAY: A High-
way Air Pollution Model. EPA Report No. EPA-650/4-74-008.
February 1975.
5. Ludwig, F.L. and R. L. Mancuso. User's Manual for the APRAC-la Urban
Diffusion Model Computer Program. Prepared for the Division of Meteor-
ology, U.S. Environmental Protection Agency, Under Contract No.
CAPA-3-68(l-69), (NTIS PB 213091). Research Triangle Park, N.C.
27711. September 1972.
6. Fairfax Air Quality Model. Submitted to County of Fairfax, Office
of Research and Statistics, Fairfax, Virginia by Engineering-Science,
McLean, Virginia, in association with Howard Needles Tammen &
Bergenkoff, Alexandria, Virginia. November 18, 1976.
42
-------
APPENDIX A
SCREENING NOMOGRAPHS
43
-------
I I I I I
LEGEND
CROSS STREET
CONFIGURATION
- I way
- 2 way
- I way
- 2 way
- 2 way
2 lane
2 lane
3 lane
3 lane
4 lane
AOT ON STREET UNDER ANALYSIS: 2 lone -2 way ( CONGESTED AREA )
( in tnouMfld* of venlclet)
Figure A-l. Critical volumes at signalized intersections.
Analysis of a 2-lane 2-way street in a con-
gested area
44
-------
u «
ui £
ec .a
si
*!
oj
O .£
2 lane - I way
2 lane - 2 way
3 lane - I way
3 lane - 2 way
4 lane - 2 way
16
ADT ON STREET UNDER ANALYSIS : 2 Ian* - 2 way ( NON- CONGESTED AREA)
(in thousand* of vehicle! )
Figure A-2. Critical volumes at signalized intersections.
Analysis of a 2-lane 2-way street in a non-
congested area
45
-------
u 2
gf
fcl
o 2
LEGEND
CROSS STREET
CONFIGURATION
2 lane
2 lane
3 lane
3 lone
4 lane
- I way
- 2 way
- I way
- 2 way
- 2 way
16
ADT ON STREET UNDER ANALYSIS : 3 lan« - 2 way ( CONGESTED AREA )
(in thousand* of vthlctot )
Figure A-3. Critical volumes at signalized intersections.
Analysis of a 3-lane 2-way street in a con-
gested area
46
-------
LEGEND
CROSS STREET
CURVE CONFIGURATION
2 lane - I way
2 lone - 2 way
3 lane - I way
3 lane - 2 way
4 lane - 2 way
16
AOT ON STREET UNDER ANALYSIS: 3 lQM-2 way (NON-CONGESTED AREA)
(in thouMnd* of vthicltt)
Figure A-4. Critical volumes at signalized intersections.
Analysis of a 3-lane 2-way street in a non-
congested area
47
-------
i
f
V) •£
in °
o •>
-
°J
O .£
LEGEND
CROSS STREET
CONFIGURATION
2 lane
lane
3 lane
3 lane
4 lane
16
AOT ON STREET UNDER ANALYSIS : 4 lane - 2 way ( CONGESTED AREA )
( in thoutandt of vehicles )
Figure A-5. Critical volumes at signalized intersections.
Analysis of a 4-lane 2-way street in a con-
gested area
-------
in «.
co o
LEGEND
CROSS STREET
CONFIGURATION
2 lone - I way
2 lone - 2 way
3 lane - I way
- 2 way
- 2 way
12
16
ADT ON STREET UNDER ANALYSIS : 3 lane - I way
(in thousands of vthiclt* )
Figure A-6. Critical volumes at signalized intersections.
Analysis of a 3-lane 1-way street
49
-------
I I I
t- —
iii Z
KJ S
l
CURVE
I I I T 1^ I
LEGEND
CROSS STREET
CONFIGURATION
2 lone - I way
2 lane -2 way
3 lane - I way
3 lane -2 way
4 lane -2 way
16
ACT ON STREET UNDER ANALYSIS : 2 lant - I way
(in thouMndt of vehicles )
Figure A-7. Critical volumes at signalized intersections,
Analysis of a 2-lane 1-way street
50
-------
2f
o
CROSS STREET
CONFIGURATION
16
ADT ON STREET UNDER ANALYSIS : 4 Ian*-2 way (NON-CONGESTED AREA )
(in thousand* of vehicles)
Figure A-8. Critical volumes at signalized intersections.
Analysis of a 4-lane 2-way street in a non-
congested area
51
-------
APPENDIX B
SAMPLE SCREENING WORKSHEETS
52
-------
PRELIMINARY SCREENING WORK SHEET- SIGNALIZED INTERSECTIONS
City /Town: Washington, D.C. State:
Transportation
Analysis By: R> Dugan Systems Analyst
(nasje) Transporta-U1"*)
Approved Bv: T* Midurski tion Systems Analyst
(DOOM) (title)
P.,, T T^-.Hr-. //. CaOO/grf X?V<.
b
Adjusted
ADC
(1977-78)
I^K
X
S K
e_
Configur-
ation
tft-Zw
X
21-/W
Street: ' S "• Sf !.<•«: S
<1_
Ailjirnti-d
APf
O977-78)
5«
e
C»nt li;vir-
2t-/^
f_
FiRurt/
i_
Mot ipoL
A/
„„,.,, M C*wt.«4 „,.. e
/^ /<
CL-tW
N
Street: les:
h^
A<1 jutted
AU]
(1977-78)
1.
Configur-
1
F>it
-------
PRELIMINARY SCREENING WORK SHEET- SIGNALIZED INTERSECTIONS
page J_of
City/Town: Washington, D.C.
Analysis By: R- Dugan
Approved By: T" Midurski
(MM)
State:
Transportation
Systems Analyst
Date: Sept. 1976
Transportafitu)
tion Systems Analyst Date: Sept. 1976
(title)
Part I Location:
Gt«*CM. /4ve
'IA fa
Part II Congested Area? X Yes: Ho
Part III Conplex Intersection or Special Case? Yes; X No; If ye«, enter location on Initial Screening
Sumary Sheet and proceed to next Intersection; If no, proceed with Part IV.
Part IV Analyze each leg separately on the torn, below.
L«3 under •n*lyfl«
*
De* I gnat Ion
Gc«**'A Avf ^A-t-cw uc}
^3^z^-- or. >>.«ru c77-7!)
31 <
^x^
<£<
£
Con£ IHUF-
• t .on
4i-2k-
]^X^
3t-2w
Crosi-ttreet det*
5trcot A^tAIM yS I..,: 4. Ml
il
Ad|u.(,'ll
APf
(1977-7I«)
-------
PRELIMINARY SCREENING WORK SHEET- SIGNALIZED INTERSECTIONS
City/Town: Washington, D.C.
Analysis By: R- Pugan
Approved By: T- Midurskl
(MM)
page Jliof
State:
Transportation
Systems Analyst
Date:Sept. 1976
Transpor- itttie)
tation Systems Analyst pate.Sept. 1976
(ttti.)
Part I Location:.
Sr 9 ^ * ST
Ayw
P«rt II Congested Area? Yes: X Ho
Part III Complex Intersection or Special Case? Y«« •- X MO: if ye». enter location on Initial Screening
Sunnary Sheet and proceed to next Intersection; If no, proceed with Part IV.
Part IV Analyze each leg seperately on the form, below.
Designation
r ST.
±XT
Ad |u7tcd
AD:
(1977-78)
8*
X
S
*c Ion
-------
APPENDIX C
WASHINGTON, D.C. HOT SPOT SCREENING RESULTS
56
-------
Intersection
16th St. at Portal Dr. N.W.
Extern Ave. at Georgia Ave. N.W.
Georgia Ave. at Kalmla Rd. /Alaska
Rd. N.W.
Kalmla Rd. at 16th St. N.W.
Alaska Ave. at 13th St. N.W.
16th St. at Holly St. N.W.
Georgia Ave. at Geranium Ave.
N.W.
Alaska Ave. at 16th St. N.W.
16th St. at Walter Reed Hospital
N.W.
16th St. at An pen St. N.W.
Georgia Ave. at Dahlia St. N.W.
Georgia Ave. at Butternut St. N.W.
Blair Rd. at Plney Branch Rd. N.W.
Cedar St. at 5th St. N.W.
Plney Branch Rd. at Butternut St.
N.W.
Cedar St. at Carroll St. N.W.
Blair Rd. at 4th St. /Cedar St.
N.W.
Carroll St. at Maple St. N.W.
Carroll St. at Willow St. /Eastern
Ave. N.W.
Aspen St. at Blair Rd. N.W.
16th St. at Van Buren St. N.W.
Georgia Ave. at Van Buren St. N.W.
Van Buren St. at 5th St. N.W.
Van Buren St. at Blair St. N.W.
16th St. at Sheridan St. N.W.
Georgia Ave. at Plney Branch Rd.
N.W.
Plney Branch Rd. at Rlttenhouse
St. N.W.
Georgia Ave. at Rlttenhouse St.
N.W.
Sheridan St. at 5th St. N.W.
N. Dakota Ave. at Sheridan St./
3rd St. N.W.
N. Capitol St. at Kansas Ave./
Chill urn PI.
Kansas Ave. at N. Dakota Ave./
Blair Rd.
Mlnnourl Avu. at Military I(U./
16th St. N.W.
MlHKnurl Ave. at 14th St. N.W.
PI nry Brnnch Rd . at Ft . Stevens
Dr. N.W.
Georgia Ave. at Peabody St. N.W.
Missouri Ave. at 13th St. N.W.
Georgia Ave. at Missouri Ave. N.W.
13th St. at Colorado Ave. N.W.
Georgia Ave. at Madison St. N.W.
Status
Identified as
having hot spot
potential
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
Determined not
to have hot spot
potential
X
X
X
X
Not analyzed -
complex int. or
sjieclal cage
X
X
X
X
X
X
X
X
X
Not analyzed -
Insufficient
data
57
-------
' Intersection
Missouri Ave. at Sth St. N.W.
16th St. at Kennedy St. N.W.
14th St. at Kennedy St. /Colorado
Ave. N.W.
13th St. at Kennedy St. N.W.
Georgia Ave. at Illlnoli Ave./
Kennedy St. N.W.
Sth St. at Kennedy St. N.W.
Mlitourl Ave. at 3rd St. N.W.
Missouri Ave. at Kansas Ave./
Kennedy Ave. N.W.
3rd St. at Kennedy St. N.W.
3rd St. at Kansas Ave./Jefferion
It. N.W.
16th St. at Colorado Ave. N.W.
Georgia Ave. at Ingraham St. N.W.
13th St. at Gellatin St. N.W.
Georgia Ave. at Gellatin St. N.W.
5th St. at Gellatin St. N.W.
Eastern Ave. at New Hampshire St.
N.W.
New Hampshire Ave. at Rlttanhoute
St. /3rd St. N.W.
Rlttenhouse St. at Eastern Ave.
N.W,
New Hampshire Ave. at Peabody St.
N.W.
Mew Hampshire Ave. at N. Capitol
St. /Kennedy St. N.W.
Missouri Ave. at New Hampshire
Ave./Rlggs Rd. N.E.
Mew Hampshire Ave. at Farragut
St. N.E.
Eastern Ave. at Rlggs Rd. N.E.
Rlfgs Rd. at Nicholson St. /6th
St. N.E.
Rlggs Rd. at Chlllum PI. N.E.
t. Dakota Ave. at Rlggi Rd. N.E.
Rlgga Rd. at Blair Rd./Ft. Totten
Dr. N.E.
Rlggs Rd. at Missouri Ave./N.
Capitol St.
N. Capitol St. at Gallatln St.
16th St. at Decatur St. N.W.
Arkansas Ave. at Delafleld PI./
13th St. N.W.
Kansas Ave. at Emerson St. /5th
St. N.W.
16th St. at Allison St. N.W.
Arkansas Ave. at Allison St. N.W.
13th St. at Buchanan St. /Iowa Ave.
N.W.
Georgia Ave. at Decatur St. N.W.
Georgia Ave. at Buchanan St. N.W.
16th St. at Upstair St. M.W.
14th St. at Arkansas Ave./T»rnu»
St. N.W.
Arkansas Ave. at Upehur St. N.W.
Status
Identified as
having hot spot
potential
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
Detemined not
to have hot spot
potential
X
X
X
X
X
X
Mot analyzed -
complex Int. or
special case
X
X
X
X
X
X
X
X
X
X
X
X
X
X
Not analyzed -
Insufficient
data
58
-------
Intersection
14th St. at Upihur St. N.W.
Roosevelt High School N.W.
13th St. at Upihur St. N.U.
Georgia Ave. at Kansas Ave./Iowa
Ave./Upshur St. N.W.
New Hampshire Ave. at Webster St.
N.W.
New Hampshire Ave. at Upihur St.
N.W.
5th St. at Upshur St. N.W.
16th St. at Arkansas Ave./
Shepherd St. N.W.
(Juorglii Avu.
-------
Intersection
Sherman Ave. at Irving St. N.W.
16th St. at Columbia Rd. /Harvard
St. N.W.
15th St. at Columbia St. N.W.
16th St. at Columbia Rd. N.W.
Harvard St. nt 15th St. N.W.
14th St. at Columbia Rd. N.W.
13th St. at Columbia Rd. N.W.
llth St. at Columbia Rd. N.W.
Columbia Rd. at Sherman Ave. N.W.
14th St. at Harvard St. N.W.
13th St. at Harvard St. N.W.
llth St. at Harvard St. N.W.
Harvard St. at Sherman Ave. N.W.
Calvert St. at Adama Mill Rd. N.W.
Columbia Rd. at 18th St. /Calvert
St. N.W.
Columbia Rd. at Ontario Rd. N.W.
16th St. at Euclid St. N.W.
15th St. at Euclid St. N.W.
14th St. at Glrard St. N.W.
14th St. at Fairmont St. N.W.
Fairmont St. at Sherman Ave. N.W.
14th St. at Euclid St. N.W.
13th St. at Euclid St. N.W.
llth St. at Euclid St. N.W.
Euclid St. at Sherman Ave. N.W.
Kalorama Rd. at Connecticut Ave./
Ann Meadow Fl . N.W.
Columbia Rd. at Kalorama Rd. N.W.
Kalorama Rd. at 18th St. N.W.
16th St. at Creacent PI. N.W.
14th St. at Clifton St. N.W.
13th St. at Clifton St. N.W.
Connecticut Ave. at Columbia Rd./
T St. N.W.
Florida Ave. at T St. N.W.
Florida Ave. at 18th St./Vernon
St. N.W.
17th St. at U St./Vernon St. N.W.
Florida Ave. at 16th St. N.W.
Florida Ave. at 15th St./W St.
N.W.
Florida Ave. at 14th St. N.W.
13th St. at Florida Ave. N.W.
Heh St. a£ Florida Ave. N.W.
Statue
Identified as
having hot spot
potential
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
Determined not
to have hot spot
potential
X
X
X
X
X
Not analyzed -
complex int. or
special case
X
X
X
X
X
X
X
Not analyzed -
insufficient
data
60
-------
Intersection
Sherman Ave. at Barry PI . N.W.
Sherman Ave. at Florida Ave. N.W.
14th St. at W St. N.W.
W St. at 13th St. N.W.
16th St. at V St. N.W.
V St. at 15th St. N.W.
14th St. at V St. N.W.
Georgia Ave. at V St. N.W.
Florida Ave. at V St. /Vermont
Ave. N.W.
New Hampshire Ave. at U St. N.W.
15th St. at U St. N.W.
U St. at 14th St. N.W.
13th St. at U St. N.W.
U St. at llth St. N.W.
Vermont St. at U St. N.W.
Florida Ave. at Connecticut Ave.
N.W.
Swann St. at 17th St. /New
Hampshire Ave. N.W.
16th St. at T St. N.W.
15th St. at T St. N.W.
14th St. at T St. N.W.
13th St. at I St. N.W.
10th St. at T St . /Vermont St. N.W.
R St. at Connecticut Ave. N.W.
19th St. at R St. N.W.
R St. at 18th St. N.W.
R St. at New Hampshire Ave. N.W.
R St. at 17th St. N.W.
1 6th St. at S St. N.W.
8 St. at 15th St. N.W.
14th St. at S St. N.W.
S St. at 13th St. N.W.
Vermont St. at S St. /llth St. N.W.
16th St. at R St. N.W.
15th St. at R St. N.W.
14th St. at R St. N.W.
13th St. at R St. N.W.
Vermont St. at R St. /12th St. N.W.
Connecticut Ave. at Q St. N.W.
Q St. at New Hampshire Ave. /18th
St. N.W.
Q St. at 17th St. N.W.
Status
Identified at
having hot a pot
potential
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
Determined not
to have hot spot
potential
X
X
X
X
X
X
Not analyzed -
complex Int. or
special case
X
X
X
X
X
X
X
X
X
X
Not analysed -
Insufficient
data
61
-------
Intersection
Q St. at 16th St. N.W.
Q St. at 15th St. N.W.
Q St. at 14th St. N.W.
Q St. at 13th St. N.W.
Q St. at Vermont Ave. N.W.
P St. at 18th St. N.W.
P St. at 17th St. N.W.
F St. at 16th St. N.W.
P St. at 15th St. N.W.
P St. at 14th St. N.W.
Massachusetts Ave. at 18th St.
N.W.
Massachusetts Ave. at 17th St.
N.W.
Klindo Inland Ave. at 15th St. N.W.
Rhode Island Ave. at 14th St. N.W.
Rhode Island Ave. at 17th St. N.W.
M St. at 16th St. N.W.
Massachusetts Ave. at 15th St.
N.W.
14th St. at N St. /Vermont St. N.W.
M St. nt 15th St. N.W.
15th St. UL L St. N.W.
L St. at Vermont Ave. N.W.
Vermont St. at K St. N.W.
14th St. at K St. N.W.
14th St. at L St. N.W.
Massachusetts Ave. at 13th St.
N.W.
Massachusetts Ave. at L St. N.W.
13th St. at M St. N.W.
L St. at 12th St. N.W.
M St. at 12th St. N.W.
M St. at llth St. N.W.
N St. at 13th St. N.W.
Rhode Island Ave. at 12th St. N.W.
Q St. at 12th St. N.W.
P St. at llth St. N.W.
Rhode Island Ave. at llth St. N.W.
Q St. at llth St. N.W.
R St. at llth St. N.W.
S St. at 10th St. N.W.
P St. at 10th St. N.W.
Q St. at 10th St. /Rhode Island
Ave. N.W,
Status
Identified as
having hot spot
potential
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
Determined not
to have hot spot
potential
X
X
X
X
X
X
X
X
X
Not analyzed -
complex Int. or
special case
X
X
Not analyzed -
Insufficient
data
62
-------
Intersection
l< St. at 10th St. N.W.
F St. at 9th St. N.W.
Q St. at 9th St. N.W.
Rhode Island at 9th St. N.W.
R St. at 9th St. N.W.
S St. at 9th St. N.W.
Florida Ave. at 9th St. /Vermont
Ave. N.W.
,Q St. at 7th St. N.W.
Rhode Island Ave. at 7th St. N.W.
S St. at 7th St. N.W.
U St. at Florida St./7th St./
Georgia Ave. N.W.
V St. at Georgia Ave. N.W.
Georgia Ave. at Bryant St. N.W.
Georgia Ave. at Howard Fl. N.W.
Georgia Ave. at Euclid St. N.W.
Georgia Ave. at Fairmont St. N.W.
Georgia Ave. at Harvard St. N.W.
Georgia Ave. at Columbia Rd. N.W.
Georgia Ave. at Irving St. N.W.
Georgia Ave. at Kenyon St. N.W.
Georgia Ave. at Park Rd. N.W.
Georgia Ave. at Princeton PI. N.W.
R St. at Marlon St. /Rhode Iflend
Ave. N.W.
R St. at 6th St. N.W.
S St. at 6th St. N.W.
Florida Ave. at 6th St. N.W.
Rhode Island Ave. at New Jersey
Ave. N.W.
New Jersey Ave. at Florida Ave.
M.W.
4th St. at Bryant Be. N.W.
4th St. at Fire Alarm Headquarter!
N.W.
5th St. at Harvard St. N.W.
Hobart Fl. at Warder St. N.U.
Warder St. at Columbia St. N.W.
Warder St. at Irving St. N.W.
Warder St. at Kenyon St. N.W.
Warder St. at Otli Fl. N.W.
Fark PI. at Irving St. N.W.
Park Fl. at Kenyon St. N.W.
Fark St. at Rock Creek/Church Rd.
N.W.
Bryant St. at lit St. N.W.
Statu*
Identified as
having hot spot
potential
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
Determined not
to have hot spot
potential
X
X
X
X
Not analyzed -
complex Int. or
special case
X
X
X
X
X
X
X
X
Not analyzed -
Insufficient
data
X
63
-------
Intersection
lit St. at Michigan Ave. N.W.
Bryant St. at N. Capitol St.
Michigan Ave. at N, Capitol St.
Church Rd. at 2nd St.A)p«hur St.
N.W.
Franklin St. at Lincoln Rd. N.B.
Michigan Av«. at Franklin Rd. N.B.
H. Capitol St. at Harewood Rd./
Fort Dr.
Irving St. at Michigan Ave. N.E.
MlclilK'i" Avu. »t Hnrowood Rd./
4th St. N.E.
Monroe St. at 7th St. N.E.
Michigan Ave. at Monroe St. N.E.
Michigan Ave. at 7th St. N.E.
Taylor St. at Harewood Rd./Fort
Dr. N.E.
Hawaii Ave. at Alllion St./
Clernont Dr. N.E.
N. Capitol St. at Hawaii Ave.
10th St. at Michigan Ave. N.E.
Taylor St. at 7th St. N.E.
Michigan Ave. at 12 h St. N.E.
10th St. at Taylor St. N.E.
Taylor St. at 12th St. N.E.
13th St. at Taylor St. /Michigan
Ave. N.E.
Varnum St. at 12th St. N.E.
Vernum St. at 13th St. N.E.
Michigan Ave. at 14th St. N.E.
S. Dakota Ave. at Hamilton St.
N.E.
S. Dakota Ave. at Galloway St.
N.E.
S. Dakota Ave. at Delafleld St./
Emerson St. N.E.
S. Dakota Ave. at Crlttenden St./
12th St. N.E.
S. Dakota Ave. at Sargent Rd. N.E.
S. Dakota Ave. at Web*ter St. N.E.
8. Dakota Ave. at Michigan Ave.
N.E.
Gallatln St. at Sargent Rd. N.E.
Eaatern Ave. at Sargent Rd. N.E.
Michigan Ave. at 18th St. N.I.
Michigan Ave. at Alllion St. N.E.
Baitern Ave. at Michigan Ave. N.I.
Weitern Ave. at 39th St. N.W.
Weitern Ave. at 41it St. N.W.
Weitern Ave. at WiaooMln Ave.
N.W.
Weatern Ave. at 44th It. N.W.
Status
Identified as
having hot spot
potential
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
Determined not
to have hot ipot
potential
X
Not analyzed -
complex int. or
•peclal case
X
X
X
X
X
X
X
X
Not analysed -
insufficient
data
X
X
X
X
X
64
-------
Intersection
Western Ave. at Jennifer St. N.W.
Western Ave. between 44th & 45th
Sts. N.W.
Western Ave. at River Rd. N.W.
Connecticut Ave. at Oliver St.
N.W.
Connecticut Ave. at McKlnley St.
N.W.
Connecticut Ave. at Livlngton St.
N.W.
Connecticut Ave. at Military Rd.
N.W.
Connecticut Ave. at Jennifer St.
N.W.
Connecticut Ave. at Huntlngton St.
N.W.
Connecticut Ave. at Nebraska Ave.
N.W.
Connecticut Ave. at 36th St. N.W.
Connecticut Ave. at Davenport St.
N.W.
Connecticut Ave. at Brandyvlna St.
N.W.
Connecticut Ave. at Albemarle St.
N.W.
Connecticut Ave. at Luna St. N.W.
Connecticut Ave. at Meazey Ter.
N.W.
Connecticut Ave. at Van Neil St.
N.W.
Connecticut Ave. at Illden St.
N.W.
Connecticut Ave. at Sedgewlck St.
N.W.
Connecticut Ave. at Porter St.
N.W.
Connecticut Ave. at Ordway St.
N.W.
Connecticut Ave. at Ma comb St.
N.W.
Connecticut Ave. at Cortland PI.
N.W.
Connecticut Ave. at Jewett St.
N.W.
Connecticut Ave. between Jewett &
Hawthorne Sti. N.W.
Connecticut Ave. at Cathedral Ave.
N.W.
Connecticut Ave. at Woodley Rd.
N.W.
Connecticut Ave. at Calvert St.
N.W.
Military Rd. at 27th St. N.W.
Military Rd. at 31st St. N.W.
Military Rd. at 32nd St. N.W.
Military Rd. at Nebraska Ave./
Broad Branch Rd. N.W.
Military Rd. at Nevada Ave. N.W.
Nevada Ave. at Nebraska Ave. N.W.
41st St. at Uviniton St. N.W.
41st St. at Military Rd./Reno Rd.
N.W.
Renn Rd. at Chevy Chase Pkwy./
Feasenden St. N.W.
ressenden It. at Nebraska Ave.
N.W.
Reno ftd. at Nebraska Are. N.W.
Reno Rd. et Albemarle St. H.W.
Status
Identified as
having hot spot
potential
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
Determined not
to have hot spot
potential
X
Not analyzed -
complex Int . or
special case
X
X
i
X
X
X
X
Not analysed -
Insufficient
data
65
-------
Intersection
Reno Rd. at Van Ness St. N.W.
Hello Rd. at Ttlden St./Springland
La. N.W.
Beth St. at Porter St. N.W.
Bath St. at Macomb St. N.W.
Beth St. at Hoodley Rd. N.W.
Bath St. at Cleveland Av». N.W.
Cleveland Ave. at 32nd St. N.W.
Cleveland Ave. at 29th St./Celvert
St. N.W.
Calvert St. between 28th & 24th
Sta. N.W.
Calvert St. at 24th St. N.W.
Wisconsin Ave. at Jennifer St.
N.W.
Wisconsin Ave. at Harrison St.
N.W.
Wisconsin Ave. at Fesienden St.
N.W.
Wisconsin Ave. ut 42nd St./
Davenport St. N.W.
Wisconsin Ave. at Brandywlne St.
N.W.
Brandywlne St. at 42nd St. N.W.
Nebraska Ave. at Albenarle St.
N.W.
Albemarle St. at Wisconsin Ave.
M.W.
Albenarle St. at 42nd St.
Wisconsin Ave. at Nebraska Ave./
40th St./Yuma St. N.W.
Wisconsin Ave. at Van Ness St.
N.W.
Nebraska Ave. at Van Ness St. N.W.
Wlfconsin Ave. north of Rodman St.
N.W.
Wisconsin Ave. at Rodman St. N.W.
Wisconsin Ave. at Porter St. N.W.
Wisconsin Ave. at Newark St. N.U.
Wisconsin Ave. south of Newark St.
N.W.
South Dakota Ave. at Taylor St.
N.E.
South Dakota Ave. at 18th St. N.E.
South Dakota Ave. at Qulncy St.
N.E.
S. Dakota Ave. at 20th St. N.E.
S. Dakota Ave. at Monroe St. N.E.
Monroe St. at 22nd Ave. N.E.
S. Dakota Ave. at Rhode Island
Ave. N.E.
S. Dakota Ave. at Carlton Ave.
N.E.
S. Dakota Ave. at Vllta St. N.E.
S. Dakota Ave. at Bladensbury Rd.
N.E.
Monroe Ave. at Rhode Island Ave.
N.K.
Eastern Ave. at Rhode Island Ave.
N.E.
Eastern Ave. at BUdensbury Rd.
N.S.
Stetus
Identified as
having hot spot
potential
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
Determined not
to have hot spot
potential
X
X
Not analyzed -
complex int. or
special case
X
X
X
X
X
X
X
X
X
X
X
Not analyzed -
insufficient
data
X
X
X
X
66
-------
Intersection
Eastern Ave. at Minnesota Av«.
N.E.
Eastern Ave. at 63rd St. N.E.
58th St. at Grant St. N.E.
Sheriff Rd. at 49th St. N.E.
Grant St. at Division Ave. N.E.
61st St. at E. Capitol St.
Sheriff Rd. at 45th St. N.E.
Deane Ave. at 49th St. /Grant St.
N-jf
• C *
E. Capitol St. at 58th St.
Deane Ave. at Minnesota Ave. N.W.
Deane Ave. at 44th St.
53rd St. at E. Capitol St.
Southern Ave. at Central Ave. S.E.
E. Capitol St. at 49th St.
E. Capitol St. at Central Aye.
Monroe St. at 18th St. N.E.
Rhode Island Ave. at Mills Ave.
N.E.
30th St. at Bladensbury St. N.E.
20th St. at Rhode Island Ave. N.E.
14th St. at Monroe St. N.E.
Rhode Island Ave. at 18th St. N.E.
Monroe St. at 12th St. N.E.
Franklin St. at 18th St. N.E.
Bladensbury Rd. at V St. /25th PI.
N.E.
10th St. at Monroe St. N.E.
Rhode Island Ave. at Franklin St.
N.E.
Bladensbury Rd. at Chapel Rd. N.E.
4th St. at Lincoln Rd. N.E.
Franklin St. at Lincoln Rd. N.E.
Franklin St. at 7th St. N.E.
I'ruukLln St. ut 10th St. N.E.
Franklin St. ut 12th St. N.E.
Franklin St. at 13th St. N.E.
Franklin St. at 14th St. N.E.
Rhode Island Ave. at Montana Ave.
N.E.
Montana Ave. at Bryant St. /14th
St. N.E.
Montana Ave. at W St. /18th St./
Adams St. N.E.
New Jersey Ave. at Florida Ave./
Rhode Island Ave. N.W.
Florida Ave. et Rhode Island Ave.
N.W.
Rhode Island Ave. ee 3rd St. N.W.
Status
Identified as
having hot spot
potential
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
Determined not
to have hot spot
potential
X
X
X
X
X
Not analyzed -
complex int. or
special case
X
X
X
X
X
X
X
X
X
Not analyzed -
Insufficient
data
»
67
-------
Intersection
Rhode I»l«ndAve. at 2nd St. N.W.
Rhode Island Ave. «t lit St. N.W.
N. Capitol St. at Rhode Island
Ave.
Rhode I«land Ave. at Lincoln Rd.
H.B.
Rhode liland Ave. at Sunmit Fl.
N.E.
Rhode Island Ave. at 4th St. N.E.
Rhode Island Ave. at South Ave.
H.E.
Rhode Island Ave. at 10th St./
Bryant St. N.E.
Rhode Island Ave. at 12th St./
Saratoga Ave. N.E.
Rhode Island Ave. at 13th St. N.E.
N. Capitol St. at T St.
Lincoln Rd. at T St. N.E.
T St. at 4th St. N.E.
9th St. at T St. N.E.
Brentwood Rd. at 9th St. N.E.
Brentwood Rd. at W St. N.E.
Saratoga Ave. at Brentvood Rd.
N.E.
Florida Ave. at 1st St. N.W.
It. Capitol St. at Randolph St.
Lincoln Rd. at R St. N.E.
R St. at N. Capitol St.
N. Capitol St. at Quincy St.
Florida Ave. at N. Capitol St.
Florida Ave. at lat St./Dlcklngton
Fl. N.E.
Florida Ave. at 4th St. N.E.
Florida Ave. at Sth St. N.E.
Florida Ave. at 6th St. N.E.
M St. at 6th St. N.E.
Florida Ave. at 8th St. N.E.
Florida Ave. at W. Virginia Ave.
N.E.
Florida Ave. at Nontello Ave. N.E.
Florida Ave. at 13th St. N.E.
Florida Ave. at Maryland Ave./
Banning Rd./H St. N.E.
Mew York Ave. at Fenn St. N.E.
New York Ave. at Brentwood Pkvy.
N.E.
New York Ave. at Brentwood Pkvy.-
North N.E.
Mt. Olivet Rd. at Brentwood Fkvy.-
South N.E.
Mt. Olivet Rd. at Irenfood ?hwy.-
North N.I.
New York Ave. it Kendall St. N.I.
New York Are. at Feaviek St. N.I.
Status
Identified as
having hoc spot
potential
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
Determined not
to have hot spot
potential
X
X
Not analyzed -
complex int. or
special case
X
X
X
X
X
X
X
X
X
X
X
Not analyse* -
insufficient
date
X
X
68
-------
Intersection
New York A v«. at 16th St. N.E.
New York Av«. at Montana Ave./
W. Virginia Ave. /18th St. N.E.
New York Av«. between Bladensbury
Rd. & Montana Ava. N.E.
New York Ava. betwaan Bladanabury
Rd. & Montana Ava. N.E.
Bladanabury Rd. at New York Ave.
N.E.
Bladansbury Rd. at Montana Ava.
N.E.
W. Virginia Ava. at Mt. Olivet
Rd. N.E.
Bladenabury Rd. at Mt. Olivet
Rd./17th St. N.E.
17th St. at M St. N.E.
L St. at 17th St. N.E.
K St. at Bladensbury Rd. N.E.
Maryland Ave. at 17th St. N.E.
Banning Rd. at 17th St. N.E.
Banning Rd. at 19th St. N.E.
Banning Rd. at 21at St. N.E.
Banning Rd. at 24th St. N.E.
Banning Rd. at 26th St. N.E.
Banning Rd. at Oklahoma Ave. N.E.
Banning Rd. between Allen &
Banning Brldgea N.E.
Banning Rd. at Anacoitla Ave. N.E.
Banning Rd. at 34th St. N.E.
Banning Rd. at Minnesota Ava. N.E.
Mlnneiota Ava. at Dlx St. N.E.
Banning Rd. at 42nd St. N.E.
Banning Rd. at 44th St. N.E.
Banning Rd. at Texas Ave./
E. Capitol St.
Banning Rd. at C St. S.E.
Banning Rd. at G St. S.E.
Banning Rd. at H St. S.E.
Daw Jersey Ava. at R St. N.W.
lit St. at Q St. N.W.
N. Capitol At. at F St.
New York Ave. at lit St./Q St.
N.E.
M St. at 4th St. N.E.
K St. at 7th St. N.E.
K St. at 8th St. N.E.
H St. at 13th St. N.E.
R St. at Hth St. M.I.
Maryland Ava. at 14th St. N.E.
Calai St. at 17th St. N.E.
Statua
Identified aa
having hot apot
potential
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
Determined not
to have hot ipot
potential
X
X
X
X
Not analyzed -
complex Int. or
apeclal eaaa
X
X
X
X
X
X
X
X
X
X
X
X
X
Not analycad -
Insufficient
data
X
69
-------
Intersection
6th St. at Q St. N.W.
New Jersey Ave. at F St. N.W.
0 St. at 1st St. N.W,
N. Capitol St. at New York Ave.
1st St. at M St. N.E.
7th St. at F St. N.W.
6th St. at F St. N.W.
0 St. at 7th St. N.W,
6th St. at 0 St. N.W.
N St. at 7th St. N.U.
6th St. at M St. N.W.
M St. at 10th St. N.W.
9th St. at M St. N.W.
M St. at 7th St. N.W.
f>th sir. nt M St. N.W.
New York Ave. at New Jersey Ave./
3rd St./M St. N.W.
New York Ave. at Klrby St. N.W.
1st St. at New York Ave. N.W.
1st St. at M St. N.W.
N. Capitol St. at M St.
L St. at 12th St. N.W.
I. St. at llth St. N.W.
L St. at 10th St. N.W.
9th St. at L St. N.W.
7th St. at L St. N.W.
L St. at 6th St. /New York Ave.
N.W.
L St. at New York Ave. /5th St.
N.W.
New York Ave, at 4th St. N.W.
Massachusetts Ave. at 10th St.
N.W.
L St. at 1st St. N.W.
12th St. at K St. N.W.
K St. at llth St. N.W.
10th St. at K St. N.W.
9th St. at Massachusetts Ave. N.W.
Massachusetts Ave. at 7th St. N.W.
6th St. at K St. N.W.
K St. at 5th St. N.W.
K St. at 4th M. N.W.
K it. at 3rd St. N.W.
K at. at MM Jersey Ave. N.W.
Status
Identified as
having hot spot
potential
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
Determined not
to have hot spot
potential
X
X
X
Not analyzed -
complex Int. or
special case
X
X
X
X
X
X
X
X
X
X
X
Not analyzed -
Insufficient
data
X
X
70
-------
Interiiectlon
lit St. at K St. N.W.
N. Capitol St. at K St.
K St. at Cul-de-Sac N.E.
lit St. at K St. N.E.
2nd St. at K St. N.E.
3rd St. at K St. N.E.
K St. at 4th St. N.E.
K St. at 5th St. N.E.
K St. at 6th St. N.E.
14th St. at I St. N.W.
12th St. at I St. N.W.
New York Ava. at 13th St./H St.
N.W.
New York Ava. at 12th St. N.W.
llth St. at I St. /New York Av«.
N.W.
10th St. at New York Ava. N.W.
I St. at 10th St. N.W.
New York Ava. at K St. N.W.
K St. at 7th St./Mai>achua«tti
Ave. N.W.
Hatiaehuaatti Ava. at 6th St./
: st. N.W.
Masiachu»att» Ava. at 5th St./
I St. N.W.
I St. at N. Capitol St.
H St. at 12th St. N.W.
H St. at llth St. N.W.
H St. at 10th St. N.W.
I St. at 9th St. N.W.
I St. at 7th St. N.W.
I St. at 6th St. N.W.
H St. at 9th St. N.W.
7th St. ut H St. N.W.
H St. at 6th St. N.W.
H St. at 5th St. N.W.
Maiachuietti Ava. at 4th St. N.W.
Haaaachuiatti Ave. at 3rd St./
H St. N.W.
Mew Jeney Ava. at H St. N.W.
lat St. at H St. N.W.
H St. at N. Capitol St.
H St. at lit St. N.E.
H St. at 2nd St. N.I.
H St. at 3rd St. M.I.
H St. at 4th St. N.I.
Statua
Identified as
having hot spot
l>otontlnl
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
Determined not
to have hot apot
potential
X
X
Not analyzed -
complex int. or
H|iuc)al CIIMC
X
X
X
X
X
X
X
X
Not analyzed -
Insufficient
tin tn
X
X
X
71
-------
Intersection
H St. at 6th St. N.E.
H St. at 7th St. N.E.
H St. at 8th St. N.E.
H St. at 9th St. N.E.
H St. at 10th St. N.E.
H St. at llth St. N.E.
H St. at 12th St. N.E.
Utli St. at 0 St. N.W.
G St. at llth St. N.W.
C St. at 10th St. N.W.
G St. at 9th St. N.W.
G St. at 8th St. N.W.
C St. at 7th St. N.W.
G St. at 6th St. N.W.
G St. at Sth St. N.W.
G St. at 4th St. N.W.
G St. at 3rd St. N.W.
Massachusetts Ave. at 2nd St. N.W.
Massachusetts Ave. at New Jersey
Ave. /1st St. N.W.
N. Capitol St. at G PI.
F St. at llth St. N.W.
F St. at 10th St. N.W.
t St. at 9th St. N.W.
F St. at 7th St. N.W.
F St. at 6th St. N.W.
F St. at New Jersey Ave. /lit St.
N.W.
N. Cnpltol St. at Massachusetts
Ave.
F St. at 4th St. N.E.
F St. at 6th St. N.E.
F St. at 12th St. /Maryland Ave.
N.E.
Maryland Ave. at 13th St. N.E.
Maryland Ave. at llth St. N.E.
(Blank)
E St. at 10th St. N.W.
E St. at 9th St. N.W.
E St. at Sth St. N.W.
E St. at 7th St. N.W.
1 St. at 6th St. N.W.
t St. at Sth St. N.W.
E St. at 4th St. N.W.
Status
Identified as
laving hot spot
potential
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
Determined not
to have hot spot
potential
X
X
X
X
X
X
X
X
X
X
X
X
X
Not analyzed -
complex int. or
special case
X
X
X
X
Not analysed -
insufficient
data
72
-------
Intersection
E St. at 3rd St. N.W.
E St. at 2nd St. N.W.
E St. at 1st St. N.W.
E St. at New Jersey Ave. N.W.
K St. at N. Capitol St.
E St. at Louisiana Av«./
Massachusetts Ave. N.E.
Massachusetts Ave. at Delaware
Ave. N.E.
E St. at 4th St. N.E.
E St. at 6th St. N.E.
I St. at 9th St. /Mary land Ave.
N.E.
D St. at 9th St. N.W.
E St. at 7th St. N.W.
D St. at Indiana Ave. /6th St. N.W.
D St. at Indiana Ave. /3rd St. N.W.
D St. at lat St. N.W.
D St. at New Jersey Ave. N.W.
D St. at Loulsiana/N. Capitol St.
D St. at Delaware Ave. N.E.
D St. at 1st St. N.E.
Massachusetts Ave. at 2nd St. N.E.
D St. at 2nd St. N.E.
D St. at Maaiachuaetta Ave. N.E.
D St. at 4th St. N.E.
D St. at 6th St. N.E.
5th St. between C St. & D St. N.E.
Maryland Ave. at Maaaachuietts
Ave./C St. /6th St. N.I.
Maryland Ave. at 8th St. N.E.
C St. at 8th St. N.E.
C St. at 9th St. N.E.
C St. at llth St. N.E.
C St. at 13th St. N.E.
C St. at Tenneisee Ave. N.E.
C St. at 14th St. N.E.
D St. at 15th St. N.E.
D St. at 17th St. N.E.
C St. at 15th St. N.E.
C St. at 17th St. N.E.
C St. at 18th St. N.E.
C St. at 19th St. N.E.
C St. at 21. t St. N.E.
Statua
Identified as
having hot spot
potential
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
Determined not
to have hot spot
potential
X
X
X
X
X
X
Not analyzed -
complex Int. or
special case
X
X
X
X
X
X
X
X
Not analyzed -
Insufficient
data
X
X
X
X
73
-------
Intersection
Oidlana Aw. at 7th St. N.W.
Indiana Ave. at 7th St./
Pennsylvania Ave. N.W.
C St. at 6th St. N.W.
6th St. at Pennsylvania Ave./
Constitution Ave. N.W.
C St. at 3rd St. N.W.
C St. at 1st St. /Indiana Ave. N.W.
Louisiana Ave. at New Jersey Ave.
N.W.
Constitution Ave. at 4th St. at
Pennsylvania Ave. N.W.
3rd St. at Pennsylvania Ave. N.W.
Constitution Ave. at Louisiana Ave.
Louisiana Ave. at lit St. N.W.
Constitution Ave. at 1st St. N.W.
Pennsylvania Ave. at 3rd St. N.W.
New Jersey Ave. at Constitution
Ave. N.W.
Delaware Ave. at C St. N.E.
C St. at 1st St. N.E.
C St. at 2nd St. N.E.
C St. at Maryland Ave./
Massachusetts Ave. /4th Ave. N.E.
C St. at 5th St. N.E.
CnnHti tution Ave. at Ttolnware Ave.
N.E.
Delaware Ave. at Capitol Bldg.
N.E.
Constitution Ave. at 1st St. N.E.
Maryland Ave. at 1st St. N.E.
Maryland Ave. at Constitution Ave.
N.E.
Maryland Ave. at 3rd St./
Constitution Ava. N.E.
Constitution Ave. at 3rd St. N.E.
Constitution Ave. at 6th St. N.E.
Massachusetts Ave. at Constitution
Ave. /7th 4 8th Sts. N.E.
Constitution Ave. at 9th St. N.E.
Constitution Ave. at llth St. N.E.
Constitution Ave. at Tennessee
Ave. /13th St. N.E.
N. Carolina Ave. at Constitution
Ave. /14th St. N.E.
N. Carolina Ave. at 15th St. N.E.
Constitution Ave. at 17th St. N.E.
Washington Dr. at 4th St. S.W.
Smithsonian Dr. at 3rd St. S.W.
Maryland Ave. at 3rd St. S.W.
Independence Ave. at 2nd St. S.W.
Independence Ave. at 1st St. S.W.
S. Capitol St. at Independence
Ave.
Status
Identified as
having hot spot
potential
X
X
X
X
X
X
X
X
X
X
X
X
X
Determined not
to have hot spot
potential
X
X
X
X
X
Not analyzed -
complex int. or
special case
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
Not analyzed -
insufficient
data
X
X
X
X
74
-------
Intersection
New .lui:ui:y UL Cu|>lli>l lUiln.
Now Jersey at Independence Ave.
S.E.
l»t St. at E. Capitol St.
E. Capitol St. at 2nd St.
E. Capitol St. at 3rd St.
E. Capitol St. at 4th St.
E. Capitol St. at 6th St.
E. Capitol St. at 8th St.
E. Capitol St. at 9th St.
E. Capitol St. at Massachusetts
Ave. /llth St./N. Carolina Ave.
E. Capitol St. at 13th St./
Massachusetts Ave./N. Carolina
Ave.
E. Capitol St. at 14th St.
E. Capitol St. at 15th St.
E. Capitol St. at 17th St.
E. Capitol St. at 19th St.
Independence Ave. at 1st St. S.E.
Independence Ave. at Pennsylvania
Ave. /2nd St. S.E.
Pennsylvania Ave. at Independence
Ave. /3rd St. S.E.
Independence Ave. at 4th St. S.E.
Independence Ave. at 6th St. S.E.
Independence Ave. at N. Carolina
Ave. /7th St. /8th St. S.E.
Independence Ave. at 9th St. S.E.
N. Carolina Ave. at 10th St. S.E.
Independence Ave. at llth St. S.E.
Independence Ave. at Kentucky Ave./
13th St. S.E.
Massachusetts Ave. at 14th St./
Independence Ave./lSth St. S.E.
Independence Ave. at 17th St. S.E.
Independence Ave. at 19th St. S.E.
Tut St. nt C St. S.W.
S. Capitol St. at C St. S.W.
C St. at New Jersey Ave. S.W.
C St. at 1st St. S.W.
Pennsylvania Ave. at 4th St. S.E.
Pennsylvania Ave. at N. Carolina
Ave. S.K.
N. Carolina Ave. at 6th St. S.E.
6th St. nt Pennsylvania Ave. S.E.
4th St. at N. Carolina Avo. S.E.
C St. in llth St. S.E.
S. Carolina Ave. at Kentucky Ave.
S.E.
Massachusetts Ave. «t 17th St.
8.B.
Status
Identified as
having hot spot
potential
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
Determined not
to have hot spot
potential
X
X
X
X
X
X
Not analyzed -
complex int. or
special case
X
X
X
X
X
X
X
X
X
X
X
X
Not analyzed -
insufficient
data
X
X
X
X
X
X
75
-------
Intersection
S. Carolina Ave. at llth St. S.E.
Delaware Ave. at D St. S.W.
S. Capitol Ave. at D St.
New Jersey Ave. at D St. S.E.
lit St. at D St. S.E.
2nd St. at D St. S.E.
D St. at 3rd St./N. Carolina Ave.
S.E.
Pennsylvania Ave. /7th St. S.E.
S. Carolina Ave. at D St. /Kentucky
S.E.
9th St. at Pennsylvania Ave. S.E.
Kentucky Ave. at D St. S.E.
D It. at 15th St. S.E.
19th St. at Massachusetts Ave.
S.E.
E St. at S. Capitol Ave. S.E.
New Jersey Ave. at N. Caroline
Ave./E St. S.E.
E St. at 3rd St. S.E.
S. Carolina Ave. at 6th St. S.E.
Pennsylvania Ave. at llth St. S.E.
Pennsylvania Ave. at 12th St. S.E.
Potomac Ave. at 17th St. S.E.
Virginia Ave. at 3rd St. S.E.
Virginia Ave. at 4th St. S.E.
C St. at llth St. S.E.
Pennsylvania Ave. at G St. /13th
St. S.E.
Kentucky Ave. at Potomac Ave. S.E.
Virginia Ave. at 4th St. /I St.
I.E.
5th St. at I St. /Virginia Ave.
S.E.
Virginia Ave. at 6th St. /I St.
S.E.
Virginia Ave. at 7th St./K St.
S.E.
Virginia Ave. at 8th St./K St.
S.E.
K St. at llth St. S.E.
K St. at 13th St. /Potomac Ave.
S.E.
Pennsylvania Ave. at Potomac Ave.
S.E.
Pennsylvania Ave. at 15th St. S.E.
M St. at Potomac Ave. /8th St. S.E.
H St. at 9th St. S.E.
M St. at llth St. S.E.
llth St. at N St. S.E.
Pennsylvania Ave. at Kentucky
Ave. /7th St. S.S.
Ridge Rd. at E. Capitol St.
Status
Identified as
having hot spot
potential
X
X
X
X
X
X
X
X
X
Determined not
to have hot spot
potential
X
Not analyzed -
complex Int. or
special case
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
Not analyzed -
Insufficient
data
X
X
X
X
X
X
X
X
X
X
X
X
76
-------
Intersection
Ridge St. at 37th St./B St. S.E.
E. Capitol St. at Stoddert PI.
S.E.
B St. at Minnesota Ave. S.E.
Minnesota Ave. at Ely PI. S.E.
Ridge St. at Texas Ave. S.E.
Bowen Kd. at 46th St. /Southern
Ave. S.E.
Ridge St. at Bowen Rd. S.E.
Alabama Ave. at Massachusetts
Ave. S.E.
Minnesota Ave. at Nelson PI. S.E.
Minnesota Ave. at Pennsylvania
Ave. S.E.
Pennsylvania Ave. at 27th St. S.E.
Pennsylvania Ave. at 28th St. S.E.
Pennsylvania Ave. at 30th St. S.E.
Pennsylvania Ave. at Branch Ave.
S.E.
Pennsylvania Ave. at 38th St./
Alabama Ave. S.E.
Pennsylvania Ave. at Southern
Ave. S.E.
Naylor St. at Minnesota Ave. S.E.
Branch Ave. at Alabama Ave. S.E.
Alabama Ave. at 30th St. S.E.
Alabama Ave. at Good Hope Kd. S.E.
Good Hope Rd. at Naylor Rd. S.E.
Naylor Rd. at Alabama Ave. S.E.
Alabama Ave. at 25th Ave. S.E.
Naylor Rd. at 30th St./Galnsvllle
St. S.E.
Good Hope Rd. at M.L. King Jr.
Ave. S.E.
Good Hope Rd. at 13th St. S.E.
Good Hope Rd. at 14th St. S.E.
Good Hope Rd. at Minnesota Ave.
S.E.
Good Hope Rd. at 16th St. S.E.
Naylor Rd. at Sultland Pkwy. S.E.
Alabama Ave. at Irving St. /Jasper
St. S.E.
Sultland Pkwy. at Southern Ave.
S.E.
Ma«uuchiisetts Ave. nt 49th St.
N.W.
Mamnchusetts Ave. at 46th St./
University Ave. N.W.
Van Ness at 46th St. N.W.
Vumu Ave. at 46th St. N.W.
Massachusetts Ave. west of Ward
Circle N.W.
Massachusetts Ave. east of Quebec
St. N.W.
Idaho St. at 39th St. N.W.
Woodley Rd. at Wisconsin Ave. N.W.
Status
Identified as
having hot spot
potential
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
Determined not
to have hot spot
potential
X
Not analyzed -
complex Int. or
special case
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
Not analysed -
Insufficient
data
X
X
X
X
X
77
-------
Intersection
Massachusetts Ave. at Cathedral
Ave. N.W.
Garfleld Ave. ac Wisconsin Ave.
N.W.
Massachusetts Ave. at Garfleld
Ave. N.W.
(Blank)
Garfleld Ave. at Reno Rd. N.W.
Observatory Circle at Reno Rd.
M.W.
Massachusetts Ave. at Normanstone
St. N.W.
Massachusetts Ave. at Rock Creek
Rd. N.W.
Massachusetts Ave. at Belmont Rd.
N.W.
Massachusetts Ave. at California
Ave. N.W.
Massachusetts Ave. at S St. N.W.
Florida Ave. at R St. N.W.
Massachusetts Ave. at R St. N.W.
Florida Ave. at Massachusetts Ave.
N.W.
Massachusetts Ave. at Q St. N.W.
Massachusetts Ave. at Connecticut
Ave. N.W.
Massachusetts Ave. at 20th St.
N.W.
F St. at 20th St. N.W.
21st St. at P St. N.W.
Q St. at 23rd St. N.W.
P St. at 23rd St. N.W.
P St. at 22nd St. N.W.
Connecticut Ave. at N St. M.W.
Connecticut Ave. at Jefferson PI.
N.W.
Connecticut Ave. at M St. N.W.
M St. at 17th St. N.W.
17th St. at De Bal St. N.W.
Connecticut Ave. at De Bal St.
N.W.
16th St. at L St. N.W.
17th St. at L St. N.W.
Connecticut Ave. at K St. N.W.
15th St. at K St. N.W.
16th St. at K St. N.W.
16th St. at I St. N.W.
Connecticut Ave. at K St. /17th
Si. N.W.
17th St. at K St. N.W.
17th St. at I St. /Jackson PI. N.W.
17th St. at I St. N.W.
MoArthur Blvd. at Loujhboro Blvd.
N.W.
I-oughboro Blvd. at Slbley Hosp.
N.W.
Status
Identified as
having hot spot
potential
\
K
X.
X.
X
X
\
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
Determined not
to have hot spot
potential
Not analyzed -
complex Int. or
special case
X
X
X
X
X
X
X
X
Not analyzed -
Insufficient
data
X
X
X
X
X
X
78
-------
Intersection
Canal Rd. at Chain Bridge N.U.
Canal Rd. at Arizona Ave. N.W.
McArthur Blvd. at Arizona Ave.
N.W.
McArthur Blvd. at Dana Fl. N.W.
Nebraska Ave. at Foxhall Rd. N.W.
Nebraska Ave. at Newark Ave. N.W.
Nebraska Ave. at New Mexico Ave.
N.W.
Gar field Ave. at Foxhall Rd. N.W.
Wisconsin Ave. north of Davis Rd.
N.W.
Celvert Rd. at 37th St. /Wisconsin
Ave. N.W.
Wisconsin Ave. at W Fl. North N.W.
Wisconsin Ave. at W Fl. South N.W.
Wisconsin Ave. at Whlteheven Fkwy.
N.W.
Wisconsin Ave. at 34th St. N.W.
Wisconsin Ave. at R St. N.W.
Wisconsin Ave. at Q St. N.W.
Wisconsin Ave. at F St. N.W.
Wisconsin Ave. at Dumbarton St./
0 St. N.W.
Wisconsin Ave. at N St. N.W.
Wisconsin Avo. at M St. N.W.
30th St. at Q St. N.W.
Q St. at 28th St. N.W.
30th St. at F St. N.W.
F St. at 28th St. N.W.
HacArthur Blvd. at V St. N.W.
MecArthur Blvd. at Whltehaven
Fkwy. /Reservoir Rd. N.W.
MtcArthur Blvd. at Reservoir Rd.
N.W.
Reservoir Rd. at Foxhall Rd. N.W.
Foxhall Rd. at D St. N.W.
MacArthur Blvd. at D St. N.W.
Foxhall Rd. at MacArthur Blvd.
N.W.
Archbold Fkwy. at Canal Rd./
MacArthur Blvd. N.W.
Canal Rd. at Whltehurst Freeway
N.W.
Canal Rd. at Francis Scott Key
Bridge N.W.
M St. at 34th St. N.W.
H St. at 33rd St. N.W.
M St. at 31st St. N.W.
N St. at 30th St. N.W.
M St. at Pennsylvania Ave. N.W.
M St. at 23th St. N.W.
Status
Identified as
having hot spot
potential
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
Determined not
to have hot spot
potential
X
X
Not analyzed -
complex Int. or
special case
X
X
X
X
X
X
X
X
X
Not analy*e4 -
Insufficient
data
X
X
X
X
X
X
X
X
X
X
X
X
X
79
-------
Intersection
M St. at 24th St. N.W.
M St. at 25th St. N.W.
M St. at 22nd St. N.W.
M St. at Nev Hampshire Ave. N.W.
M St. at 21at St. N.W.
M St. at 20th St. N.W.
M St. at 19th St. N.W.
New Hampshire Ave. at 20th St.
N.W.
Reservoir Kd. at 38th St. N.W.
Reservoir Kd. at 35th St. N.W.
Reservoir Rd. at 34th St. N.W.
Q St. at 34th St. N.W.
Q St. at 33rd St. N.W.
22nd St. at New Hampshire Ave.
N.W.
Pennsylvania Ave. at 26th St. N.W.
Pennsylvania Ave. at 25th St. N.W.
L St. at 23rd St. N.W.
L St. at 22nd St. N.W.
L St. at 21st St. N.W.
L St. at 20th St. N.W.
L St. at 19th St. N.W.
L St. at 18th St. N.W.
K St. at 25th St. N.W.
K St. at 24th St. N.W.
K St. at Pennsylvania Ave. N.W.
Pennsylvania Ave. at 22nd St./
K St. N.W.
K St. at 22nd St. N.W.
K St. at 21at St. N.W.
K St. at 20th St. N.W.
K St. at 19th St. N.W.
K St. at 18th St. N.W.
Virginia Ave. at Potomac Pkwy.
N.W.
Virginia Ave. at 27th St. N.W.
I St. at 23rd St. N.W.
Pennsylvania Ave. at 21st St. N.W.
I St. at 20th St. N.W.
1 St. at 19th St. N.W.
I St. at 18th St. N.W.
I St. at Pennsylvania Ave./
20th St. N.W.
Virginia A»e. at New Hampshire
Ave. N.W.
Statue
Identified a«
having hot spot
potential
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
Determined not
to have hot spot
potential
X
X
X
Not analyzed -
complex Int. or
special case
X
X
X
X
X
X
X
X
X
X
Not analysed -
Insufficient
data
X
X
X
X
80
-------
Intersection
H St. at 23rd St. N.W.
Pennsylvania Ave. at H St. /19th
St. N.W.
H St. at 18th St. N.W.
H St. at 17th St. N.W.
Connecticut Ave. at H St. N.W.
H St. at 16th St. N.W.
G St. at 23rd St. N.W.
G St. at 22nd St. N.W.
G St. at 21st St. N.W.
C St. at 20th St. N.W.
G St. at 19th St. N.W.
G St. at 18th St. N.W.
Pennsylvania Ave. at 17th St. N.W.
Pennsylvania Ava. at Jackson Ave./
W. Executive Ave. N.W.
Virginia Ave. at 23rd St./F St.
N.W.
f St. at 19th St. N.W.
F St. at 18th St. N.W.
New York Ave. at 17th St. N.W.
17th St. at F St. N.W.
23rd St. at E St. N.W.
Virginia Ave. at 22nd St./E St.
N.W.
E St. at 21st St. N.W.
B St. at 20th St. N.W.
E St. at 19th St. N.W.
E St. at New York Ave. /18th St.
N.W.
New York Ave. at 17th St. N.U.
Virginia Ave. at 21it St. N.W.
New York Ave. at 20th St. N.W.
E St. at 19th St. N.W.
I St. at 18th St. N.W.
Virginia Ave. at 20th St. N.W.
23rd St. at C St. N.W.
C St. at 21«t St. N.W.
Constitution Ave. at 23rd St. N.U.
Constitution Ave. at National
Academy of Science N.W.
Constitution Ave. at Independence
Dr. N.W.
Constitution Ave. at 21st St. N.U.
Pennsylvania Ave. at H St. N.U.
Constitution Ave. at 20th St. N.U.
Constitution Ave. at 19th St. N.U.
Statue
Identified aa
having hot spot
potential
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
Determined not
to have hot spot
potential
X
X
X
X
Not analyzed -
complex Int . or
special case
X
X
X
X
X
X
X
X
Not analyzed -
Insufficient
data
X
X
X
81
-------
Intersection
Vermont Ave. at I St. N.W.
15th St. at I St. N.W.
H St. at Vermont Ave. N.W.
H St. at 15th St. /Madison Ave.
N.W.
H St. at 14th St. N.W.
Pennsylvania Ave. at Madison East
N.W.
Pennsylvania Ave. at New York Ave./
15th St./G St. N.W.
Nev York Ave. at 14th St. N.W.
C St. at 14th St. N.W. I
G St. at 13th St. N.W. /
F St. at 15th St. N.W.
7 St. at 14th St. N.W.
P St. at 13th St. N.W.
F St. at 12th St. N.W.
Pennsylvania Ave. at Madison
East N.W.
Pennsylvania Ave. at 15th St. N.W.
Pennsylvania Ave. at E St. /14th
St. N.W.
I St. at 13th St. N.W.
E St. at 12th St. N.W.
E St. at llth St. N.W.
E St. at 17th St. N.W.
E St. at 8. Executive Ave. N.W.
E St. at E. Executive Ave./
Ellipse Rd. N.W.
E St. at 15th St. N.W.
I St. at Pennsylvania Ave. N.W.
Pennsylvania Ave. at 13th St. N.W.
Pennsylvania Ava. at 12th St. N.W.
Pennsylvania Ava. at llth St./
D St. N.W.
Pennsylvania Ave. at 10th St. N.W.
Pennsylvania Ave. at 9th St. N.W.
Virginia Ave. at 18th St. N.W.
Virginia Ave. at Constitution Ave.
N.W.
Constitution Ave. at 17th St. N.W.
Constitution Ave. at 16th St. N.W.
Constitution Ave. at 15th St. N.W.
Constitution Ave. at 14th St. N.W.
Constitution Ave. at 12th St. N.W.
Constitution Ave. at llth St. N.U.
Constitution Ave. at 9th St. N.W.
Constitution Ave. at 7th St. N.W.
Statua
Identified as
having hot spot
potential
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
Determined not
to have hot spot
potential
Not analyzed -
complex int. or
special case
X
X
X
X
X
X
X
X
Not analyzed -
insufficient
data
82
-------
Intersection
7th St. at Madison Dr. S.W.
7th St. at Washington Dr. S.W.
14th St. at Smithsonian Dr. S.W.
7th St. at Smithsonian Dr. S.W.
14th St. at Jefferson Dr. S.W.
Independence Ave. at 15th St. S.W.
Independence Ave. at 14th St. S.W.
Independence Ave. at 12th St. S.W.
Independence Ave. at 10th St. S.W.
Independence Ave. at 9th St. S.W.
Independence Ave. at 7th St. S.W.
Independence Ave. at 6th St. S.W.
Independence Ave. at Maryland Ave./
4th St. S.W.
Independence Ave. at 3rd St. S.W.
14th St. at C St. S.W.
C St. at 12th St. S.W.
C St. at Maryland Ave. /7th St.
S.W.
Maryland Ave. at 6th St. S.W.
6th St. at C St. S.W.
C St. at 4th St. S.W.
C St. at 3rd St. S.W.
C St. at 2nd St. S.W.
15th St. at Maine Ave. S.W.
Milne Ave. at 15th St. Ramp S.W.
14th St. at Tidal Basin Approach
S.W.
D St. at 12th St. S.W.
Maryland Ave. at 10th St. S.W.
(Blank)
9th St. at D St. S.W.
D St. at 7th St. S.W.
E St. at 7th St. S.W.
E St. at 4th St. S.W.
Maine Ave. at 10th St. S.W.
Virginia Ave. at S. Capitol Ave.
G St. at 7th St. S.W.
C St. at 4th St. S.W.
10th St. at Maine Ave. S.W.
Maine Ave. at 9th St. S.W.
I St. at 7th St. S.W.
I St. at 6th St. S.W.
Status
Identified as
having hot spot
potential
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
Determined not
to have hot spot
potential
X
X
X
X
X
Not analyzed -
complex Int . or
special case
X
X
X
X
X
Not analyzed -
Insufficient
data
X
X
X
X
X
X
X
X
X
X
X
83
-------
Intersection
I St. at 4th St. S.W.
I St. at 3rd St. S.W.
I St. at Delaware Avo. S.W.
I St. at S. Capitol St. S.W.
Main* Ave. at M St. S.W.
M St. at 6th St. S.W.
M St. at 4th St. S.W.
M St. at 3rd St. S.W.
M St. at Canal St. S.W.
M St. at Half St. S.W.
M St. at S. Capitol St. S.W.
M St. at 1st St./N«w Jersey St.
S.E.
M St. at 2nd St. S.E.
N St. at 4th St. S.E.
S. Capitol St. at Sultland Pkvy.
Botanic Garden!
Firth-Starling at Sultland Fkwy.
S.E.
W St. at H. L. King Jr. Ave. S.E.
Morris Rd. at M. L. King Jr. Ave.
S.E.
Howard Rd. at M. L. King Jr. Ave.
S.E.
Stanton Rd. at M. L. King Jr. Ave.
S.E.
H. 1. King Jr. Ave. at St.
Elizabeth's Hoop. S.E.
P.rU St. nt 17th St. S.K.
Stnnton Rd. nt Sultlnnd Pkwy. S.E.
23rd St. at Alabama Ave. S.E.
Alabama Ave. at Stanton Ter. S.E.
Bruce St. at Stanton Rd. S.E,
Stanton Rd. at Alabama Ave. S.E.
Alabama Ave. at Contrast St. S.B.
M. L. King Jr. Ave. south of
Milwaukee PI. S.E.
S. Capitol St. at Portland Rd. S.E.
M. L. King Jr. Ave. at Portland
Rd. S.E.
Alabama Ave. at Wheeler Rd. S.E.
Wheeler Rd. at Mississippi Ave.
S.E.
Valley Ave. at Wheeler Rd. S.E.
Wehler PI. at Wheeler Rd. S.E.
Barnaby St. at Wheeler Kd. S.E.
Southern Ave. at Wheeler M. S.E.
Alebena Ave. at Ranele H. S.E.
Alabama Ave. at 13th St. S.I.
Status
Identified as
laving hot spot
potential
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
Determined not
to have hot spot
potential
X
Not analyzed -
complex int. nr
special case
X
X
X
X
X
Not analysed -
Insufficient
data
X
X
X
X
X
X
X
X
X
X
X
X
84
-------
Intersection
M. L. King Jr. Ave. at Trenton
PI. S.E.
S. Capitol St. at M. L. King Jr.
Ave. S.E.
4th St. at Mississippi Ave. S.E.
Atlantic St. at 4th St. S.E.
Atlantic St. at 1st St. S.E.
Atlantic St. at Mississippi Ave.
S.E.
Chesapeake St. at S. Capitol St.
S.E.
S. Capitol St. at Elmlra St. S.E.
Cialveston St. at 1st St./S.
Capitol St. S.E.
S. Capitol St. at LlvliiK»ton St.
S.E.
S. Capitol St. at Southern Ave.
S.E.
M. L. King Jr. Ave. «t Chesapeake
St. S.E.
Chesapeake St. at Overlook Ave.
Status
Identified aa
having hot spot
potential
X
X
X
X
X
Determined not
to have hot spot
potential
Not analyzed -
complex Int . or
special cane
X
X
X
X
X
Not analyzed -
Insufficient
data
X
X
X
85
-------
APPENDIX D
APPLICATION OF THE HOT SPOT GUIDELINE TECHNIQUES:
DETAILED DISCUSSION
The purpose of this appendix is to provide a detailed description of the
techniques used in applying the Hot Spot Guidelines to the study of
potential carbon monoxide problems in Washington, D.C. To accomplish
this, each of the three phases of the Guidelines procedure is discussed
using the analysis of the Wisconsin Avenue - Albemarle Street intersection
as an example.
HOT SPOT SCREENING
As indicated in Section III, numerous data elements required during applica-
tion of the Guidelines were obtained from the District of Columbia Depart-
ment of Transportation, Bureau of Traffic Engineering and Operations. The
first of these used in the screening analysis was a traffic signal locations
map; this map identified the specific locations to be analyzed since the
scope of the project specified that only signalized intersections were to
be considered. The street names for each signalized intersection identified
from the traffic signal locations map were entered on a Screening Worksheet;
Figure D-l, below shows the worksheet for the example intersection.
The next step involved determining several general features of the inter-
section based on a traffic volume map, a street log, and general knowledge
of the city. The data provided by the volume map and street log were suf-
ficient to Identify the basic configuration of the intersection and to
86
-------
Part I
Part II
Lout loo:
irle It.
Congested Area? Tee; I Ho.
Part III Cobles Intersection or Special Case? tes; i Ho; If yes, enter location on Initial Screening
Siamsry Sheet and proceed to next intersection; It no, proceed vltb Part IV.
Part IV Analyse each la( separately on the fora, below.
Leg under analysis
ii
Deslgnet loa
b
Adjusted
an
(1977-7«)
c_
Configur-
ation
Cross-street data
Street: Leg: Street: Lee:
d
Adjusted
ADT
(1*77-7*)
e_
Cosflcur-
ation
f_
PI fere/
curve used
&
Hot spot
lad tested
Street i Lei:
h
Adjusted
ADT
(1977-78)
i
Configur-
ation
1
Pigure/
curve ueed
k
Hot spot
indicated
Street: Leg:
] I
1 1
Figure D-l. Sample worksheet used in the preliminary
screening of Washington, D.C.
determine whether or not to consider the intersection to be complex or a
special case. The maps provided by the Bureau of Traffic Engineering
and Operations Indicated that the Wisconsin Avenue — Albemarle Avenue in-
tersection is a basic cross intersection. The volume map indicated that
the daily traffic volumes were about 7,000 on Albemarle Street and about
28,000 on Wisconsin Avenue. From this information, then, it was established
that the intersection of Wisconsin Avenue and Albemarle Street was neither
complex nor a special case as defined by the Guidelines. Also, from a
general knowledge of the city, it was assumed that the intersection is not
located in a congested area nor was it located in a street canyon. Gen-
erally, congested areas are those where substantial interference occurs
within a traffic stream as a result of a high rate of activity with respect
Complex intersections are defined in the Guidelines as intersections with
unusual geometry (more than four legs) or very high volumes on all legs;
special cases are defined as intersections controlled by traffic officers
or with special signal control during specific hours of the day.
87
-------
to turning movements, pedestrian crossings, parking and unparking maneuvers,
etc.; this type of activity occurs most frequently in the central business
district. Based on this information, Parts I, II and III of the worksheet
were completed as shown in Figure D-l.
Since Part III of the worksheet indicated that the intersection is neither
complex nor a special case, the analysis continued. If it had been indi-
cated that the intersection was either complex or a special case, further
analysis using the screening procedure would not have been appropriate;
rather, the intersection would be considered for further analysis using
the more detailed verification procedure.
At this point, several entries were made in Part IV of the worksheet. The
designation of the first leg to be analyzed was entered in column a, and
the corresponding volume and configuration entered in columns b and c,
respectively. As an example, the designation for the south leg of Wiscon-
sin Avenue was entered in column a as Wisconsin South. The value entered
in column b was an adjusted ADT derived by increasing the ADT indicated
on the volume map by 8 percent and rounding to the nearest thousand. For
the south leg of Wisconsin Avenue, the flow map indicated an ADT of
28,000; increasing this by 8 percent yielded 30,240, which was rounded
to 30,000. This was done to more closely reflect 1977 ADT (the flow
map represented 1975 ADT). The entry in column c identified the number
of lanes and the directional use (one-way or two-way operation) of the
south leg of Wisconsin Avenue. The entry 4L-2W indicates a four-lane,
two-way facility. The street leg provided the total pavement width of
each street section in the city; an estimate of the number of lanes for
any particular section was obtained by dividing the pavement width by the
width of an "average" traffic lane (3 to 3.5 meters). The traffic signal
locations map showed the location and direction of all one-way streets in
the city.
The next entry involved the cross-street data. The designation of the
cross-street (with respect to the south leg of Wisconsin Avenue) was entered
88
-------
on the first line as Albemarle west and Albemarle east. The adjusted ADT's
for the west leg and east leg of Albemarle Street were entered in columns d
and h, respectively, and the configurations for both were entered in col-
umns e and i. The information entered in these columns was derived in the
same manner as the data entered in columns b and c for Wisconsin Avenue,
as described previously. The worksheet at this point is shown in
Figure D-2, below.
The next step involved selecting the appropriate screening nomograph from
the Hot Spot Guidelines. Eight separate nomographs are provided in the
Guidelines for screening signalized intersections (see Appendix A). Se-
lection of the particular nomograph is based on the configuration of the
intersection leg being analyzed; in this instance, the leg under analysis
has a four-lane, two-way configuration, therefore the nomograph for four-
lane, two-way streets in noncongested areas was selected. Each nomograph
Part I
Put II
lotattea! Htseantlsi AveeMs st >1ieasrle »t. aV
Coeeasterf Areat teat 1
Part III Coanlex Interaction or Special Case? Tes;^ *»; If yee. enter location on Initial Screening
Suneary Sheet and proceed to next Intersection; If no, proceed vlth Part IT.
Part I* Analyse each leg Mparately oo the fora, below.
Leg under analyst*
a
Destination
Htsconsln South
]^>
-------
includes five curves corresponding to five cross-street configurations.
Since the cross-street (Albemarle) configuration was identified as two-
lane, two-way, curve B was selected. The figure number (as it appears in
the Hot Spot Guidelines) corresponding to the nomograph for four-lane, two-
way streets in noncongested areas, and the cross-street curve designation
were entered in columns f and j of the worksheet.
To determine whether or not the south leg of Wisconsin Avenue is a poten-
tial hot spot, its volume (from column b) and the cross-street volume
(from column d) were used as the x-coordinate and y-coordinate, respec-
tively, to locate a point on the nomograph (see Figure D-3); as can be
seen, this point lies well beyond curve B on the nomograph, implying that
hot spot potential exists on the south leg of Wisconsin Avenue. The com-
pleted worksheet is shown in Figure D-4.
The intersection name and result of the screening were then entered on a
summary sheet (see Appendix C). Since the screening indicated that hot
spot potential did exist, this intersection was further analyzed using the
hot spot verification process as described in the following paragraphs.
HOT SPOT VERIFICATION
Ordinarily, hot spot verification would be conducted at each location
identified in the screening process as having hot spot potential or being
either a complex intersection or special case. For the purposes of this
project, however, the verification process was applied to only 29 loca-
tions throughout the city.
The first step in the hot spot verification process was to assemble the
appropriate data regarding various traffic operating characteristics and
the physical layout of the intersection being analyzed. The first element
obtained for each location was a site sketch showing:
90
-------
ut
in
o
-
8J
S.!
LEGEND
CROSS STREET
CONFIGURATION
16
ADT ON STREET UNDCft ANALYSIS : 4 Ian*-Z way (NON-CONGESTED AREA )
(in thoutondt of vthicltt)
Figure D-3. Critical volumes at signalized intersections.
Analysis of a 4-lane 2-way street in a non-
congested area
91
-------
Pect I
Locette*; UlKt»ftm_trm** at albeaaile it. •
Pert II Conceited treat Tee; » «o.
r»rt III Coaplex Interaction or Special CM*? _ Tesjj _ Ho; If yes. cater location on Initial Screening
Suaaary Sheet mat proceed to next intersection; If no, proceed with Part IT.
Part IV Analyze each leg separately on the form, belov.
Leg under analysis
ii
Designation
Htaconaln South
]^>~<^
b
Adjusted
ADT
(1977-78)
30C
X
«
Configur-
ation
41^ 2M
X
Cross-street data
Street: Albeawrle Lei: ««« Street: Albeavrle Leg:Eut
d
Adjusted
ADT
(W77-78)
-------
N
STREET
STREET
CLOSED
NOTES
I. NO PARKING PERMITTED
2. RECEPTOR IS $. SIDEWALK
3. LIGHT PEDESTRIAN ACTIVITY
4. ESTIMATED CRUISE SPEED
IS 30 M.RH.
5. NOT A STREET CANYON
\
-------
The next data element required Is traffic volume data. For each location
analyzed traffic volume data were provided by the Bureau of Traffic Engin-
eering and Operations. The data consisted of summaries of turning move-
ment counts taken for a 10-hour period during 1976. This summary for the
Wisconsin Avenue — Albemarle Street intersection is reproduced in Table D-l.
Traffic speed estimates are required also. The Hot Spot Guidelines sug-
gest that cruise speed information can be obtained for a location by
conducting speed studies or from estimates based on guidance provided in
the Guidelines. For this project, speeds were estimated.
Also required are traffic signal data. Of particular importance are the
numbers of phases and the ratio of the green time allocated to each approach,
to the total cycle length. These types of data are generally on file with
the agency holding jurisdiction over a particular installation. Signal
data for this study were obtained from the Bureau of Traffic Engineering
and Operations. These data consisted of charts showing the phasing and
timing for each signal and Indicating the type of control used (i.e.,
fixed time or actuated, etc.).
Estimates of the vehicle-type distribution occurring on each roadway are
required. For this project, it was assumed that the vehicle population
consisted of 88 percent light-duty vehicles, 8 percent light-duty trucks,
3 percent heavy-duty gasoline-powered vehicles, and 1 percent heavy-duty
diesel-powered vehicles. The fraction of vehicles operating in the cold-
start mode and the hot start mode were also estimated. These estimates
were that 5 percent of the vehicles using any roadway would be operating
in the cold mode and 10 percent would be in the hot-start mode.
These data elements were then used in conjunction with the various tables
and graphs provided in the Guidelines to estimate the maximum 8-hour aver-
age concentration of carbon monoxide likely to occur at the intersection
of Wisconsin Avenue and Albemarle Street. The completed worksheet for
94
-------
Table D-l. 10-HOUR TURNING MOVEMENT COUNT SUMMARY - WISCONSIN AVENUE AT ALBEMARLE
STREET, N.W.
Hour
ending
8 a.m.
9 a.m.
10 a.m.
11 a.m.
12 noon
2 p.m.
3 p.m.
4 p.m.
5 p.m.
6 p.m.
Total
Wisconsin Avenue
Northbound
Left
23
14
35
49
82
67
97
76
29
11
483
Through
595
750
786
722
844
916
819
893
991
1,187
8,503
Right
—
—
—
—
—
—
—
—
—
—
—
Total
618
764
821
771
926
983
916
969
1,020
1,198
8,986
Southbound
Left
—
—
—
—
—
—
—
—
—
—
—
Through
1,373
1,386
920
809
856
842
895
861
881
996
9,819
Right
10
28
22
39
42
28
54
42
31
52
348
Total
1,383
1,414
942
848
898
870
949
903
912
1,048
10,167
Albemarle Street
Eastbound
Left
33
54
45
59
60
44
60
61
64
65
545
Through
1
—
—
—
—
—
—
—
—
—
—
Right
75
137
61
64
80
86
69
105
68
65
810
Total
109
191
106
123
140
130
129
166
132
130
1,356
Total
2,110
2,369
1,869
1,742
1,964
1,983
1,994
2,038
2,064
2,376
20,509
Source: District of Columbia Department of
tions, counts taken 11 May 1976.
Transportation, Bureau of Traffic Engineering and Opera-
-------
computing the estimate is provided below along with an annotated instruc-
tion sheet for completing the worksheet; several tables and graphs used in
the computations are provided.also.
96
-------
WORKSHEET No. 2
Calculation of CO Concentration Along Roadways
With Interrupted Flow (Intersections)
1.
2.
3.
4.
5.
6.
7.
Site
i -
n. -
i
Xi -
Vi '
S. -
Main road
identification 1^
Intersection approach identification
Number of traffic lanes in approach i
Roadway/receptor separation (m)
Peak-hour lane volume in each approach
(veh/hr)
Cruise speed (mph) on each approach
/!»£.» «IW
1
3
7
4oo
30
2
3
17
350
3o
Crossroad
AtM/KAULB
3
I
X
45
30
4
—
X
-
-
8.
9.
10.
11.
12.
13.
14.
a. Type of intersection (signalized or
unsignalized)
b. For signalized intersections:
i) (G/Cy)i - Green time/signal cycle
ratio for approach 1
ii) Vcross - Effective crossroad
volume (veh/hr)
Le - Queue length on approach 1 (m)
Qe - Excess emission rate (g/m-sec)
Qf. - Free-flow emission rate (g/m-sec)
. -, Normalized concentration contri-
">:L bution from excess^emissions on
nppro.nch i
40
7
£50
0.014.64
Cde. - Distance correction factor, excess
emissions
X . - Concentration contribution from ex-
& "1 *5
' cess emissions on approach i (mg/nr)_
X - Total contribution from excess emis-
sions (mg/nr)
MO
255
3-5
a 00003
I.OQ
l.Z
. . - Normalized concentration con-
"' n tribution from free-flow emis;-
sions on main roadway
Figure D-6. Verification worksheet — Wisconsin Avenue at
Albemarle Street, NW
97
-------
Main road
16. |^r
Normalized concentration
contribution from free-flow
emission on crossroad
.cross
17. Cdf - Distance correction factor, free-
flow emissions
18. a. X, . Concentration contribution
,main from free-flow emissions on
main road
1.10
b. Xr - Concentration contribution
L cross
' from free-flow emissions on
crossroad (mg/m^)
19. X, - Total concentration from free-flow
emissions (mg/m3)
~ Total concentration, uncorrected
(mg/m3)
Crossroad
120
o.i
3-8
£3.7
21. Vehicle mix: a. P 09 7, b. FLDT o/. c.
22. Year/location/vehicle-type correction factor:
Year Q77
a. C _ Q.Q? b. C
c.
d.
Altitude
(low or high) Low
State
(Calif, or other)
LDVnc
CLDT
cat
Q.ZO
d' CLDTnc -^
f.
HDV-D
0.53
23. Temperature/cold-start correction factor:
a. Percent cold-starts
b. Percent hot-starts
c. Temperature ( F)
d. Ccs
cat
4.47
e. Ccs
nc —————•
24. C_, - Total emission correction factor
£i
25.
. .
' " r
- 1-hour average concentration
resulting from vehicle emissions
(mg/m3)
41-7
Figure D-6 (continued). Verification worksheet —Wisconsin Avenue at
Albemarle Street, NW
98
-------
26. X_ Q - 8-hour average CO concen-
*> 8"hr tration (mg/m3)
27. X.. - 8-hour average background con-
' centration (mg/m3)
28. \p ~ Total CO concentration, 8-hour
T*8"hr average (mg/m3)
29. X_ - . • Total CO concentration, 8-hour 2-2.4
T»8""r average (ppm) \
Figure D-6 (continued). Verification worksheet —Wisconsin Avenue at
Albemarle Street, NW
99
-------
WORKSHEET NO. 2 EXPLANATION OF DATA AND OPERATIONS
USED TO GENERATE EACH LINE ENTRY*
1. Intersection identification. Enter street names; instructions for
identifying the main street are provided under Step 2, below.
2. The pollutant concentration should be determined at the position
where the maximum projected level is moat likely to occur. The
optimum receptor placement ie determined according to the following
guidelines.
a. The receptor should be located on an approach which has in-
terrupted traffic flow.
b. 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 hour volume.
c. If the approaches have an unequal number of lanee, and
the approach having the greatest number of lanes also has
the highest lane volume, the receptor should be located
on that approach.
d. If the approach having the largest number of lanes does
not have the greatest lane volume, Table D-2 and Figure D-7
must be used to determine receptor placement. The average
cruise speed for the approaches must be known to use
Table D-2. See Section TV.B.l.e of the Guidelines for aid
in making this estimation.
Enter Table D-2 using the lane volume of the approach
having the most lanes as Vmain to determine the queue
length, Le, which develops on that approach. Use this
quantity to enter Figure D-7 to determine the normalized
concentration, (xu/Q)e. Next designate the largest lane
volume as Vmain an<^ ^nter Table D-2 to determine the queue
length which develops on the corresponding approach. Again
use Figure D-7 to find the resulting normalized concen-
tration (yu/Q)Q. The receptor should be located on the ap-
proach which yields the highest (yu/Q)e value.
The actual instructions provided in the Guidelines are shown in italics;
comments regarding the specific application to the example appear in reg-
ular type.
Table and Figure designations given here do not necessarily correspond to
the designations in the Hot Spot Guidelines; the corresponding designation
is noted on each table and figure provided here, however.
100
-------
Table D-2. EXCESS EMISSIONS AND QUEUE LENGTHS AT SIGNALIZED INTERSECTIONS AS FUNCTIONS OF
MAXIMUM LANE VOLUME PER HOUR ON MAIN ROAD (HORIZONTAL AXIS) AND MAXIMUM LANE
VOLUME PER HOUR ON CROSSROAD (VERTICAL AXIS)3
excess emssiOMS. bUMis/ftitiosticNC. **u wtue tenet*, me c*uix sfttu is 10, >PM.
e.o«9«3 *.o o.e o.« •.• «.t «.o «.• o.e •.• •.«
2 40, 0 40.0 796.5 ••*»*** 40.0 40.0 «0.0 40,0 40.0 40.0 40.0 40. 0 40.0 40, •
2 1300 »0.0 0.1)2654 0.02155 O.OlBbl 0.00940 0.0 0.0 0.0 0.0 0.0 0.0 0,0 0.0 0.0
^ 40.0 1901.4 347.2 670.4 ******* 40. u 40.0 40.0 40.0 40.0 40.0 40.0 40.0 40. •
(O
w 1200 «o.o 0.02542 o.o2i37 o.oieae o.oi6S6 o.ooa27 o.o o.o o.o o.o o.o o.o o.o o.o
Jj 40. «l 36/.9 205. / 314.7 698.6 •••«•*• 40.0 40.0 40.0 40.0 40.0 40.0 40.0 40.0
M
W UOO tO.O 0,«2452 0.02131 0.01912 0.01/OS 0,01501 0,00787 0.0 0.0 0.0 0.0 0.0 0.0 0.0
g 40.0 173.2 139.0 197.4 333.4 757.5 ******* 40.0 40.0 40.0 40.0 40.0 40.0 40.0
•w
1000 »0.0 0.02384 0.02142 0.01951 U. 01/61 0.01567 0.01371 0.00671 0,0 0.0 0.0 0.0 0.0 0.0
Q 40.0 101. * 101.2 139,4 211.9 362.9 626.6 ******* 40.0 40.0 40.0 40.0 40.0 4«.«
900 +0.0 0.02342 0.0216% 0. 01998 U. 01821 0.01637 0.01449 0.012S6 0.0 0.0 0,0 0,0 0.0 0.0
40.0 70.2 77.3 10S.O 1S1.1 231.0 39b.2 899.1 40.0 40.0 40.0 40.0 40.0 40.0
8«0 »0.0 0.02326 0.02201 0.020S2 0.0186b 0.01709 0.01b28 0.01342 0,01151 O.OObl* 0.0 0,0 0.0 0.0
40.0 51.0 60.9 82.3 114.5 164.5 2S0.5 427.4 971,8 ******* 40.0 40.0 40.0 40, »
O 700 «0.0 0.02265 0,02250 0.02111 0.01951 0,01782 0.01606 0.01427 0.01243 0.01053 0.00438 0.0 0.0 0.0
_ 00. 0 40.0 49.1 66.0 89.8 124.2 177.2 268.6 457.6 1042.1 ******* 40.0 40.0 40.0
K
O 600 «O.U2481 O.OlBOb 0.023U9 0.02175 0.02019 0.01853 0.01683 0.01509 0.01332 0.01149 0.00960 0,00406 0.0 0.0
W 66.8 40.0 40.1 53.8 71.9 96.6 132.4 187.8 283.9 484.0 1107.7 *•***•• 40.0 40.0
gj 500 to. 01502 0.01485 0.01954 0.02239 0.02083 0.01921 0.01755 0.01587 0.01417 0.01242 0,01061 0.00872 0.00357 0.0
Cu «0.0 4(T.O 40.0 44.0 58.0 76.3 101.4 137.9 195.0 294.7 504,4 1164.9 ******* 40,0
S 400 *0. 00910 0.01237 0.01643 0.020b>3 0.02140 U. 01980 0.01820 0.01656 0.01495 0.01329 0.01158 0.00978 0.00788 0.0*293
5 40.0 40.0 40.0 40.0 46.5 60.2 78,2 103.1 139.5 197.1 298.8 515.5 1208.3 •***•••
i-l
P 300 to, 00666 0.1*1621 0.01340 0.01665 U.0!9<»b 0.02024 0.01870 C. 01718 0.01565 0.01410 0.01250 0.01082 0.00904 0.00711
40.0 40.0 40.0 10.0 40.0 Ufc.6 59.4 76. b 100,4 135.6 191.8 292.6 511,1 1226.4
U
§ 200 +0.00516 0,00802 0.01034 0.0126V 0.01499 C.01'57 0.91897 0.01757 0.01619 0.01480 0.01336 0.01185 0.01024 0.0*846
2 40.0 40.0 46.0 40.0 40.0 40.0 43.3 5u,7 70.0 41.5 123.5 175.3 269.6 479, S
|2 104 *0.00363 (.00532 0.00674 0.00815 0.00966 0.01134 0.01327 6.V1553 0.01646 0.01533 0.01417 0.01295 0.01162 0.01011
40.0 40.0 40.0 40.0 40.0 40.0 40.0 40.0 44,4 56.6 73.7 99.2 140.7 217.1
1«« 2*0 300 40V 500 6tO 700 800 900 10»0 1100 1200 1300 14*0
Appears as Table IV-2 in the Guidelines.
MAXIMUM LANE VOLUME PER HOUR ON MAIN ROAD (VEHICLES/HOUR)
-------
•to
•00 -
TIC -
TOO
too
SCO
100
10 M
10 TO
«U«UC LIMTH.L, (•)
Note: Figure IV-3 in HSG.
Figure D-7. CO concentration contribution from excess emissions on
approach 1 as a function of number of lanes and queue
length
102
-------
For this application, paragraph c applies. This is evident upon
examining the site sketch (Figure D-5) and the traffic volume data
shown in Table D-l. The highest hourly volume through the inter-
section occurs during the period from 5 p.m. to 6 p.m. During
this period the volumes occurring on the northbound and southbound
approaches of Wisconsin Avenue were 1198 and 1048 vehicles, res-
pectively, while on Albemarle Street the volume was 130 vehicles.
The average lane volume for these approaches, then, are 399 north-
bound, 349 southbound, and 65 on Albemarle. Therefore, by para-
graph c, the receptor should be located on the east side of the
northbound approach of Wisconsin Avenue. Wisconsin Avenue, then,
is the main street while Albemarle is designated the cross street.
Each traffic stream (all lanes in one direction of travel) approach-
ing the intersection should be assigned an identification number
with regard to the receptor site as depicted below:
t
The assigned identification numbers are shown on the intersection
sketch shown in Figure D-5.
3. Enter the number of lanes per each intersection approach.
This information is obtained from the site sketch in Figure D-5.
4. Enter the roadway/receptor separation distance, x^3 for approaches
1 and 2. This is the minimum perpendicular distance in meters
from the centerline of the traffic stream approaching the inter-
section to a line parallel to the roadway drawn through the re-
ceptor site.
This information is obtained from the site sketch in Figure D-5.
103
-------
5. Enter the peak-hour traffic volume per lane, V^ (vehicles/hour)
for each intersection approach. This is the total traffic stream
volume divided by the number of approach lanes.
As indicated in step 2, the peak hour occurs between 5 p.m. and
6 p.m. The lane volumes for Wisconsin Avenue are 400 vehicles
per lane northbound, 350 vehicles per lane southbound; on
Albemarle Street, the lane volumes are 65 vehicles per lane.
6. Enter the roadway cruise speed, S^ (mph), for each intersection
approach.
As indicated previously, the cruise speed through the intersection
was estimated to be 30 mph.
7. a. Enter type of intersection (signalized, stop or yield).
Traffic signals are used at this intersection.
b. For signalized intersections:
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 traffic movement in the total cycle length.
This information was provided by the District of Columbia
Department of Transportation Bureau of Traffic Engineer-
ing and Operations.
ii) Determine the effective crossroad volume, VOPO88, using
the following equation:
v line 5 7. ,.
cross ~ line ?.b.i + 0.05 ~
For this intersection, V
cross
/ 400 \
\0.56 + 0.05 /
(400)
250
8. Determine the queue length, Le (m), which develops on approach 1 as
follows:
For signalized intersections use the appropriate section of
Table D-2 based on oruiee speed S^ (line 6). Enter the table
using Vma^n = V^ (line 5) and Vait083 = line ?.b.ii.
Queue length for approach 1 is 40 meters (from Table D-2).
104
-------
9. Enter the corresponding excess emission rate., Q (g/m-sec), from
Table D-2. e
This value is obtained by interpolating between 0.01264 and 0.01665,
which reflect values for crossroad volumes of 200 and 300 vehicles,
respectively; since the crossroad volume is 250, the interpolation
yields:
[(0.
01665 - 0.01264)(0.5) + 0.01264 = 0.01464
10 Enter the free-flow emission rate, Qf^ (g/m-sec), for each
traffic stream using Table D-3. Enter the table using line 6i
(cruise speed) and line 5 (average lane volume) for each approach.
The values obtained for approaches 1, 2 and 3 are 0.00169, 0.00148,
and 0.0003, respectively.
11. Determine the normalized concentration contribution from excess
emissions, (yu/Q) • for each approach as follows:
& jl ^"
a. The contribution from approach 1:
Enter Figure D-8 at the appropriate queue length, Le (line 8),
to obtain (\u/Q)e^. Multiply this value by the number of
traffic lanes in approach 1 (line 3), and record result.
For approach 1, (Wisconsin Avenue northbound), the value is
320 *3 - 960.
b. The contribution from approach 2:
Enter Figure D-9, curve 2, at the same Le, used in part (a),
(line 8), to obtain (\u/Q)e 2. Multiply this value by the
number of traffic lanes in approach 2 (line 3), and record
result.
For approach 2 (Wisconsin Avenue southbound) the value is
85 x 3 - 255
a. The contribution from approach 3:
Signalized intersections - Enter Figure D-9, curve 3 at
Le (line 8) to obtain (~^u/Q)e $. Multiply by the number of
traffic lanes in approach 3 ('Line 3)3 and record result.
Unsignalized intersections (\u/Q) . = 0.
e, t
For approach 3 (Albemarle Street eastbound) the value is
40 x 2 - 80.
12. Determine the. distance correction factors. Cde-:
t*-
a. Approach 1: obtain Cde.. from Figure D-10 at the appropriate
roadway/receptor separation distance x.. (line 4).
105
-------
Table D-3. FREE FLOW EMISSION RATE, Qf, IN GRAMS PER METER-SECOND AS A FUNCTION OF LANE VOLUME AND
VEHICLE SPEED ON ROADWAYS WITH INTERRUPTED FLOW (INTERSECTIONS)
CHOI it EMISSIONS, bNAMS Ptfl »EIEH-$ttOftl>
"S, «5 tO.OOU.i'} 0.000/1 U.OOlOn O.OU1«1 0.00177 0.00212 O.U0247 0.00263 0.00318 0.00353 0.00389 0,001?" 0.00459 O.OOM4
40 to.00036 V.00073 0.00109 0.00145 0.00182 0.00216 0.00254 0.00
-------
INTIftStCTIOM
MO
_~ *00
7
•
?
S T60
1
| TOO
I
1 -
M
5 «oo
jj MO
•
1 •°°
| 460
e 400
M
N
s >60
•00
SSO
100
/
/
/
/
/
/
1
1
0 M tO
OUIUI
/
/
/
/
f
/
/
/
/
/
100 tOO 100 MO
LIN«TH,L« (»>
1000
Note: Figure IV-4 in HSG.
Figure D-8. Normalized CO concentration contribution from excess
emissions on approach 1
107
-------
INTERSECTIONS
« 7.
m
I
I
I
w
N
ISO
140
ISO
120
110
100
90
i
4. *°
t TO
SO
80
40
90
20
10
SO 100 ISO SOO
EFFECTIVE QUEUE LEMOTH.L*
SOO
Note: Figure IV-5 in HSG.
Figure D-9. Normalized CO concentration contributions from excess
emissions on approaches 2, 3, and 4
108
-------
INTERSECTIONS
o
VO
O IO ZO SO 40 50 6O TO SO SO IOO MO ISO 130 140 ISO ICO 170 ICO
i ROAC/RECEPTOR SEPARATION, Mf
Note: Figure IV-8 in HSG.
Figure D-10. Distance correction factor for excess emission contributions at intersections
-------
For approach 1, the x.^ value is 7 meters; from Figure D-10,
the correction factor is 1.1.
b. Approach 2: compute Cde2 by dividing the value obtained
from Figure D-10 at the appropriate distance x% dine 4)
by 0.79:
Cde (at xj
Cde* -
0.79
For the approach 2 , the x- value is 17 meters ; from
Figure D-10, the correction factor is: 0.75/0.79 = 0.95.
c. Approach 3: Cde^ = 1 for signalized intersections .
13. Multiply (line 9) x (line 11)^ x (line 12)^ for all approaches to
obtain the concentration, \e^, at the receptor resulting from ex-
cess emissions on each approach.
For approach 1: xel = (0.01464) (960) (1.1) - 15.5
For approach 2: xe2 * (0.01464) (255) (0.95) - 3.5
For approach 3: xe3 * (0.01464) (80) (1.0) » 1.2
14. Sum all line IS entries to obtain the total concentration, \e,
resulting from excess emissions at the intersection.
3
2 X - 15.5 + 3.5 + 1.2 - 20.2
i-I ei
IS. Enter Figure D-ll at the appropriate queue length, Le (line 8),
and record the (yu/Q) ,. value using the curve designated MAIN ROAD.
Le - 40; therefore, from Figure D-ll, (xu/Q)f - 380
16. Similarly, determine the normalized concentration contribution from
free- flow emissions on the crossroad, (\u/Q) ~ aroas- Use the
CROSSROAD curve of Figure D-ll. Enter the graph at the same queue
length as in step IS.
Le • 40; therefore, from Figure D-ll, (xu/Q), - 120
I • cross
17. Enter the distance correction factors, Cdf^, for free- flow emis-
sions from the main roadway. Obtain these values from Figure D-12.
a. Cdf . is the correction factor at x = x1 (line 7).
*& i.
x - x1 - 7 meters; therefore, from Figure D-12, Cdf- -1.1
110
-------
INTCftUCTIOMS
f
2
T
!
!
I
s
N
moo
700
600
SOO
400
300
290
200
ISO
100
90
80
70
60
50
40
30
20
10
MAIN ROAO
^
S^
CROSS*
^S^
OAD _
"-^
^
^
^^
x^1
^H
^
--—
s'
—-
^
=a
^^^
"*
»— =
-
0 M 10 40 SO 60 70 60 M 100 ISO tOO
IFPECTIVK OUKUE LCN6TH, Lt («•»•»•)
Note: Figure IV-7 in HSG.
Figure D-ll. Normalized CO concentration contributions from free-flow
emissions on each lane of roadways at intersections
111
-------
1.3
1.2
o
3 I.I
K
! '-°
o
& 0.9
0.7
0.6
a °*
O 0.4
O.3
0.2
O.I
IMTCMCCTIOMS
20 30 40 90
•0 1O 90 <0 KM IK) 1*0 ISO 140 ISO *0 I TO
• NOAO/MECC^TOK SEMMATION.MUr*
Note: Figure IV-9 in HSG.
Figure D-12. Distance correction factor for free-flow emission contributions at
intersection locations
-------
b. Cdfn is the correction factor for the departure lanes on leg 13
evaluated at x = the roadway /receptor separation distance for
the departure stream. Usually this value is x% dine 4) „.
x = x_ = 17 meters; therefore, from Figure D-12, Cdf» =0.95
18. Compute the concentration contribution from free- flow emissions
from each roadway, x~.
a- X.P „,,,„•„ - Hne *s (line S)1 (line 17)- (line 10) ,
j jiTtCLufL J. J. J.
+ (line 3), (line 17) _ (line 10),.
xe,main = (380) (3) (1'1) <°-00169> + (3) (0.95) (0.00148) = 3.7
b. Xf QTOgg = 1-ine ^ \dine 3) s (line 10) 3 + (line 3) 4 (line 10)
Xf ,,™o= • (120) (2) (0.003) + (0.0) (0.0) = 0.1
iy cross
19. Sum line 18 entries to obtain total contribution from free-flow
emissions3 Xf
Z Xf =Xfjffialn+Xf>cro88=3.7+0.1=3.8
20. Sum line 19 and line 14 to obtain the total CO concentration from
intersection emissions, Xmt (uncorreated) at the receptor.
XT - Xf = Xe « 3.8 + 20.2 - 24.0
21. Enter vehicle mix data - the relative proportions of light-duty
vehicles (LDV), light-duty trucks (LDT), heavy-duty gasoline-fueled
trucks (HDV-G), and heavy-duty diesel trucks (HDV-D).
As mentioned previously, the assumption was made that the vehicle
fleet using any roadway would consist of 88 percent LDV's, 8 per-
cent LDT's, 3 percent HDV-G's and 1 percent HDV-D's.
22. Enter the appropriate year/location correction factor for each
vehicle type:
a. CTTW . • 0.07 (from Table D-4)
LDVcat
b. CLDVnc - 0.69 (from Table D-4)
c. CLDTcat - 0.20 (from Table D-5)
d. CTTVP - 0.86 (from Table D-5)
LDTnc
113
-------
Table D-4. LIGHT-DUTY VEHICLE EMISSION CORRECTION FACTOR (BASE
YEAR 1975) FOR CATALYST-EQUIPPED VEHICLES (C )
AND NONEQUIPPED VEHICLES 3 °3
Year
1975
1976
1977
1978
1979
1980
1985
1990
Low altitude,
non-Calif.
non-cat
0.98
0.82
0.69
0.55
0.44
0.32
0.06
0
cat
0.02
0.05
0.07
0.08
0.09
0.10
0.09
0.07
High altitude,
non-Calif .
non-cat
1.71
1.45
1.23
1.00
0.81
0.60
0.12
0
cat
0.04
0.10
0.13
0.15
0.15
0.16
0.11
0.07
Low altitude,
Calif.
non-cat
0.98
0.83
0.69
0.56
0.44
0.33
0.05
0
cat
0.01
0.03
0.04
0.05
0.06
0.07
0.08
0.07
High altitude,
Calif.
non-cat
1.71
1.47
1.23
1.02
0.81
0.62
0.10
0
cat
0.02
0.06
0.07
0.09
0.10
0.11
0.10
0.07
aThese correction factors reflect the imposition of interim fed-
eral CO emission standards (for the low-altitude and high-altitude
areas) through model year 1977 and the statutory standard there-
after. For California, the CO correction factors reflect the Ca-
lifornia interim standards through the 1977 model year and the
statutory standards thereafter. Should amendments to the Clean
Air Act proposed in March 1975 become law, correction factors for
1978 and later years may be altered. In the event Congress amends
the Clean Air Act, this table should be altered accordingly. This
may be done using Supplement 5 to AP-42 (Reference 2).
Note: Table IV-6 in HSG.
114
-------
Table D-5. LIGHT-DUTY TRUCK EMISSION CORRECTION FACTOR (BASE
YEAR 1975) FOR CATALYST-EQUIPPED TRUCKS (C )
AND NONEQUIPPED TRUCKS (CLDT ) C*
Year
1975
1976
1977
1978
1979
1980
1985
1990
Low altitude,
non-Calif .
non-cat
1.20
1.03
0.86
0.71
0.59
0.43
0.12
0
cat
0.05
0.12
0.20
0.24
0.25
0.26
0.27
0.26
High altitude,
non-Calif.
non-cat
2.08
1.79
1.51
1.25
1.05
0.80
0.25
0
cat
0.10
0.26
0.37
0.41
0.41
0.39
0.31
0.26
Low altitude,
Calif.
non-cat
1.21
1.03
0.85
0.71
0.59
0.43
0.12
0
cat
0.05
0.12
0.20
0.24
0.25
0.26
0.27
0.26
High altitude,
Calif.
non-cat
2.09
1.80
1.51
1.25
1.05
0.80
0.25
0
cat
0.10
0.26
0.37
0.41
0.41
0.39
0.31
0.26
Note: Table IV-7 in HSG.
Table
D-6. HEAVY-DUTY GASOLINE- FUELED TRUCK EMISSION CORRECTION
FACTOR (BASE YEAR 1975)
Year
1975
1976
1977
1978
1979
1980
1985
1990
Low altitude,
non-Calif.
3.81
3.71
3.62
3.49
3.31
3.02
2.44
2.13
High altitude,
non-Calif.
5.95
5.83
5.72
5.62
5.50
5.27
4.93
4.85
Low altitude,
Calif.
3.79
3.66
3.53
3.39
3.22
2.94
2.40
2.13
High altitude,
Calif.
5.79
5.75
5.59
5.46
5.35
5.13
4.86
4.85
Note:
Table
Table IV-8 in HSG.
D-7. HEAVY-DUTY DIESEL TRUCK EMISSION CORRECTION FACTOR
(BASE YEAR 1975) I
Year
1975-
1990
Low altitude,
non-Calif .
0.53
High altitude,
non-Calif.
0.53
Low altitude,
Calif.
0.53
High altitude,
Calif.
0.53
Note: Table IV-9 in HSG.
115
-------
e. Cffl)V_G - 3.62 (from Table D-6)
f. C - 0.53 (from Table D-7)
Also, note that the evaluation year is 1977, Washington, D.C. is
a low altitude city, and the city is located in an area other than
California.
23. a. Enter present cold-starts.
This was estimated to be 5 percent.
b. Enter percent hot-starts.
This was estimated to be 10 percent.
a. Enter ambient temperature
This was assumed to be 30 F.
d. Determine cold-start/temperature correction factor, CasQa+> for
catalyst-equipped vehicles from Table D-8.
Ccscat - 4.47
e. Determine cold- e tart /temperature correction factor, Cos , for
unequipped vehicles from Table D-9.
- 1.27
no'
24. Compute the total emission correction factor, €„, according to the
following equation:
= line 21a
+ line 21b
(line 2Ze)(line 22b) + (line 23d)(line 22a)
(line 23e)(line 22d) + (line 23d)(line 22c)
CE - (o.
+ (line 2lc)(line 22e) + (line 21d)(line 22f)
).88) |"(1.27)(0.98) + (4.470(0.02)1 + (0.08) [ (1.27) (1.20)
+ (4.47(0.05)1 + |"(0.03)(3.81)1 + [(0.01(0.53)1 = 1.32
25. Multiply line 24 by line 20 to obtain the corrected CO concentration.
Corrected CO concentration - 24.0 * 1.32 - 31.7 mg/m3
116
-------
Table D-8. COLD-START TEMPERATURE CORRECTION FACTORS
FOR CATALYST EQUIPPED LIGHT-DUTY VEHICLES
(LDV) AND LIGHT-DUTY TRUCKS (LOT)
% cold
starts
Temperature F
20
30
40
50
60
70
80
a. Assuming 10 percent hot-start operating vehicles
0
10
20
30
40
1.21
10.48
19.75
29.01
38.28
1.21
7.72
14.21
20.72
27.22
1.21
5.77
10.32
14.87
19.42
1.22
4.39
7.57
10.75
13.93
1.22
3.43
5.64
7.85
10.06
1.22
2.76
4.30
5.04
7.38
1.23
2.28
3.33
4.37
5.42
b. Assuming 20 percent hot-start operating vehicles
0
10
20
30
40
1.41
10.68
19.95
29.22
38.49
1.42
7.92
14.42
20.93
27.43
1.43
5.98
10.53
15.08
19.64
1.43
4.61
7.79
10.97
14.15
1.44
3.65
5.86
8.07
10.48
1.44
2.99
4.53
6.07
7.61
1.45
2.50
3.55
4.60
5.65
c. Assuming 30 percent hot-start operating vehicles
0
10
20
30
40
1.62
10.89
20.16
29.43
38.70
1.63
8.13
14.63
21.14
27.64
1.64
6.19
10.74
15.30
19.85
1.65
4.83
8.00
11.18
14.36
1.66
3.87
5.98
8.29
10.49
1.67
3.21
4.75
6.29
7.83
1.68
2.73
3.78
4.83
5.87
Note: Table IV-11 in HSG.
117
-------
Table D-9. COLD-START TEMPERATURE CORRECTION FACTOR FOR LDV's
AND LDT's NOT EQUIPPED WITH CATALYST (Ccs )
•L Cold
start
0
10
20
30
40
50
60
70
80
90
100
Temperature (°F)
20
1.0
1.81
2.62
3.43
4.24
5.05
5.85
6.66
7.47
8.28
9.09
30
1.0
1.55
2.09
2.64
3.18
3.73
4.27
4.82
5.36
5.91
6.45
40
1.0
1.40
1.80
2.20
2.60
3.00
3.40
3.80
4.20
4.60
5.00
50
1.0
1.31
1.62
1.92
2.23
2.54
2.85
3.16
3.47
3.77
4.08
60
1.0
1.24
1.49
1.73
1.98
2.22
2.47
2.71
2.96
3.20
3.45
70
1.0
1.20
1.40
1.60
1.77
1.99
2.19
2.39
2.59
2.79
2.99
80
1.0
1.16
1.33
1.49
1.65
1.82
1.98
2.14
2.31
2.47
2.63
118
-------
26. Multiply line 25 by 0. 7 to obtain the highest expected 8-hour average
concentration resulting from vehicle emissions.
8-hour average concentration = 31.7 x 0.7 = 22.2 mg/m3
27. Enter 8-hour average background CO concentration in mg/m3. Assume
2.6 mg/m3 if sufficient data to develop local background estimates
are not available.
Local estimates were not available, therefore 3.6 mg/m3 was
assumed.
28. Sum lines 26 and 27 to obtain maximum expected 8-hour average con-
centration in the vicinity of the intersection (mg/m3).
Maximum expected 8-hour average concentration expected is
22.2 mg/m3 + 3.6 mg/m3 -25.8 mg/m3 (22.4 ppm).
119
-------
Hot Spot Modeling
A detailed discussion of the procedures used in exercising these Inter-
sections Midblock Model will not be included here; rather, a description
of the input data and its sources will be provided. For a comprehensive
discussion of the application of the models, the reader should consult
the User's Manual for the Intersection-Midblock Model.2
In order to apply the Intersection-Midblock Model, three basic data ele-
ments are required. The first is meteorological data reflecting both
micro-and mesoscale conditions for the specific hours being analyzed.
The specific elements required Include average hourly wind speed and
direction, and mixing height. These data were obtained from the summary
of observations made at National Airport in Washington, D.C.
The second type of information required included traffic data. These
included hourly volume on each lane, vehicle-type distribution, traffic
signal data, cruise speed, and the percentage of vehicles operating in the
cold mode. Volume data and traffic signal information were obtained from
the District of Columbia Department of Transportation, Bureau of Traffic
Engineering and Operations for the Wisconsin Avenue — Albemarle Street
intersection, and from a report entitled Fairfax Air Quality Model3 for
the Fairfax County site. The vehicle-type distributions and percentage
of cold operating vehicles used in the verification procedure were also
used in the modeling effort. Estimates of cruise speed were made based on
field observations.
The third data element required concerned defining the physical and operat-
ing characteristics of each site. For the Wisconsin Avenue - Albemarle
Street intersection, the site sketch developed for the verification phase,
supplemented with additional data regarding the placement of the existing
air quality monitor, was adequate for this application. A site sketch
provided in Reference 3 was used for the Fairfax County Site. The streets
were Identified using a grid coordinate system to identify link endpoints
120
-------
(nodes). Grid coordinates were also used to define the assumed receptor
location; for both sites, the assumed receptor was placed at the actual
monitor location.
These data provided the input required by the model to compute hourly
average carbon monoxide concentrations resulting from emissions on the
nearby highway system. A discussion of the actual results of the compari-
son of the modeled and measured concentrations is presented in Section IV.
REFERENCES
1. Guidelines for Identification and Evaluation of Localized Violations
of Carbon Monoxide Standards. GCA/Technology Division, Bedford,
Massachusetts. Prepared for U.S. Environmental Protection Agency,
Research Triangle Park, N.C. Contract No. 68-02-1376.
2. User's Manual for the Intersection - Midblock Model. GCA/Technology
Division, Bedford, Massachusetts. Prepared for U.S. Environmental
Protection Agency, Research Triangle Park, N.C. Contract No.
68-02-1376 (Draft Final Report).
3. Fairfax Air Quality Model. Submitted to County of Fairfax, Office
of Research and Statistics, Fairfax, Virginia by Engineering-Science,
McLean, Virginia, in association with Howard Needles Tammen &
Bergendoff, Alexandria, Virginia. November 18, 1976.
121
-------
APPENDIX E
SAMPLE VERIFICATION WORKSHEETS
122
-------
WORKSHEET No. 2
Calculation of CO Concentration Along Roadways
With Interrupted Flow (Intersections)
1.
2.
3.
4.
5.
6.
7.
Site identification
i - Intersection approach identification
n. - Number of traffic lanes in approach i
x - Roadway/receptor separation (m)
V. - Peak-hour lane volume in each approach 550
1 (veh/hr)
S. - Cruise speed (mph) on each approach
a. Type of intersection (signalized^or
unsignalized)
b. For signalized intersections:
Main road
£«>
)
O.OOliS
,H
>«
S.4
O-OOl'jl
K
,.,
,.,
o.ooo^g
-
/. 0
0.5
X - Total contribution from excess emis-
sions (mg/irr)
- Normalized concentration con-
' n tribution from free-flow emis-
sions on main roadway
4/0
123
-------
Main road
16. (—T- I ,. - Normalized concentration
101 f .cross *.•!_*.• * 'c *i
\ I ' contribution from free-flow
emiSjgion on crossroad
(lO'V1)
17. Cdf - Distance correction factor, free-
flow emissions
18. a. Xf . - Concentration contribution
' from free-flow emissions on
main road (mg/nP)
b. Xf - Concentration contribution
' from free-flow emissions on
crossroad (mg/m3)
19. Xf - Total concentration from free-flow
emissions (mg/m3)
i-as
20.
Crossroad
110
0-4
- Total concentration, uncorrected
(mg/m3)
21. Vehicle mix: a. P
88 % b. P
~
c P
C* *
HDV-G
P '
'HDV-D
22. Year/location/vehicle-type correction factor:
Altitude
Year O77 (low or high) £•«"*
State
(Calif, or other) °rttf*-
a.
LDVcat
0-07
C' CLDTcat °'
o c ^t^.
e' SlDV-G
f.
o. 6C
« S3
23. Temperature/cold-start correction factor:
a. Percent cold-starts S%
b. Percent hot-starts '0 '/.
O • r
c. Temperature ( F) 3o f
d. Cos
cat
4.47
e. Ccs
nc
1-17
24. C,, - Total emission correction factor
£i
25. X_ . . - 1-hour average concentration
' ~. resulting from vehicle emissions
(mg/m3)
4.Z.I
124
-------
26. 5C. ft - 8-hour average CO concen-
E> 8"hr tration (mg/m3)
27. X_ - 8-hour average background con-
U,8—hr
centration (mg/m3)
Total 00 concentra
average (mg/n.3) 33.1
28. X_ e . - Total CO concentration, 8-hour
l,o-nr
29. Xp o u ~ Total CO concentration, 8-hour
1,o—nr f \
' average (ppm)
125
-------
WORKSHEET No. 2
Calculation of CO Concentration Along Roadways
With Interrupted Flow (Intersections)
1. Site identification
2. i - Intersection approach identification
3. n. - Number of traffic lanes in approach i
4. x - Roadway/receptor separation (m)
5. V. - Peak-hour lane volume in each approach
(veh/hr)
6. S. - Cruise speed (mph) on each approach
•
7. a. Type of Intersection (signalized^or
unsignalized)
b. For signalized intersections:
Main road
4* ST
Iw
2
t
i 2,80
3o
2
2
/3
*.0
30
Crossroad
E ST. KJW
3
Z.
X
>5o
30
4
—
X
-
Jo
i) (G/Cy)i - Green time/signal cycle °-55
ratio for approach 1
ii) V,
cross
- Effective crossroad
volume (veh/hr)
8. Le - Queue length on approach 1 (m)
9. Qe - Excess emission rate (g/m-sec)
10. Qf. - Free-flow emission rate (g/m-sec)
40
XXX
o. 01
11. I—} - Normalized concentration contri-
\" /e> bution from excess emissions on
approach i (10"3m"1)
12. Cde. - Distance correction factor, excess
emissions
13. X . - Concentration contribution from ex- 7.0
e> cess emissions on approach i (mg/m3;
O.ODIZ
64o
/. I
7.o
)
o.«o»j4
170
/. 1
/.6
0.00^3
So
1.0
o.a
-
-
1.0
-
14. X - Total contribution from excess emis-
sions (mg/m3)
15
tst\
' V" /f.
- Normalized concentration con-
n tribution from free-flow ends- 380
sions on main roadway (10~3m"'*-)
126
-------
Main road
16.
.cross
Normalized concentration
contribution from free-flow
emission on crossroad
17. Cdf - Distance correction factor, free-
flow emissions
18. a. X_ . - Concentration contribution
' from free-flow emissions on
main road (mg/m3)
b. Xf - Concentration contribution
' from free-flow emissions on
crossroad (mg/m3)
19. Xf - Total concentration from free-flow
emissions (mg/m3)
M
Crossroad
JZO
/P_I_«\
(f+e)
(mg/m3)
21. Vehicle mix: a.
~ Total concentration, uncorrected
"-5
b.
c. P
RDV_G
d. P
RDV_D
22. Year/location/vehicle-type correction factor:
Altitude
Year '^77 (low or high) _
State
(Calif, or other)
C o.o7
LDVcat —
b. C
LDVnc
d. C.
'LDTnc
0-84
e C_ 3-6Z
e' SlDV-G —=
f. C^, °'S*
23. Temperature/cold-start correction factor:
a. Percent cold-starts
b. Percent hot-starts
c. Temperature (°F)
d. Ccs
joT
'cat
-4.47
e. Ccs
nc
I-Z7
24. C_ - Total emission correction factor
Ci
1-hour t
resultii
(mg/m3)
25. X_ . . - 1-hour average concentration
' resulting from vehicle emissions
127
-------
26. X.., Q - 8-hour average CO concen-
E» 8"hr tration (mg/m3)
27. Xp - 8-hour average background con-
' " r centration («"»/«3\
28. X_ * Total CO concentration, 8-hour ^ f
* average (mg/m3)
29. X_ 0 , - Total CO concentration, 8-hour .
x«o—nr * \. is ti.
average '«"">« • «. • ~r
128
-------
WORKSHEET No. 2
Calculation of CO Concentration Along Roadways
With Interrupted Flow (Intersections)
1. Site identification
2. i - Intersection approach identification
3. n. - Number of traffic lanes in approach i
4. x - Roadway/receptor separation (m)
5. V. - Peak-hour lane volume in each approach
1 (veh/hr)
6. S. - Cruise speed (mph) on each approach
7. a. Type of intersection (signalized)or
unsignalized) —
b. For signalized intersections:
Main road
S-tWoT* Ave
1
I
£
i JQO
SS
2
e
a
£00
35
Crossroad
/?«•»€
3
i
X
«5o
35
(14x4 4
4
e
X
4<>o
35
i) (G/Cy)i - Green time/signal cycle 0.45
ratio for approach 1
ii) V
cross
- Effective crossroad
volume (veh/hr)
8. Le - Queue length on approach 1 (m)
9. Qe - Excess emission rate (g/m-sec)
10. Qf. - Free-flow emission rate (g/m-sec)
7oo
XXX
0-0/74-1
11.
- Normalized concentration contri-
bution from excess emissions on
approach i (10"3m"1)
12. Cde - Distance correction factor, excess
emissions
13. X . - Concentration contribution from ex-
e' cess emissions on approach i (mg/m3
14. X - Total contribution from excess emis-
sions (mg/m )
o.oatO
Hoo
1. 1
"^ ZM
o,.za,
m
„
4.3
o.<»lK
<.
l-o
1.0
0.00154
O
A 0
-
WE
es.4
15.
- Normalized concentration con-
tribution from free-flow emis-
sions on main roadway
7oo
129
-------
Main road
16.
w*.
cross
Normalized concentration
contribution from free-flow
emission on crossroad
17. Cdf - Distance correction factor, free-
flow emissions
18. a. Xf . Concentration contribution
' n from free-flow emissions on
main road (mg/m3)
b. Xf - Concentration contribution
' ° from free-flow emissions on
crossroad
19. Xf - Total concentration from free-flow
emissions (mg/m3)
20. X,,..» ~ Total concentration, uncorrected
-------
26, X., 0 . - 8-hour average CO concen-
12' 8"hr tration (mg/m3)
27. X_ R , - 8-hour average background con-
' centration (mg/nv3)
28. X-, 8 . - Total CO concentration, 8-hour
* average (mg/in?)
XT a t, " Total CO concentration, 8-hour SO-3
x«o**rxir / \
' average (ppm)
131
-------
TECHNICAL REPORT DATA
(Please read Instructions on the reverse before completing)
REPORT NO.
EPA-450/3-77-053
2.
3. RECIPIENT'S ACCESSION NO.
4. TITLE AND SUBTITLE
Characterization of the Washington, D.C., Carbon
Monoxide Problem
5. REPORT DATE
October 1977
6. PERFORMING ORGANIZATION CODE
7 AUTHOR(S)
Theodore P. Midurski and Victor L. Corbin
8. PERFORMING ORGANIZATION REPORT NO.
GCA-TR-77-11-G
9. PERFORMING ORGANIZATION NAME AND ADDRESS
GCA Corporation
GCA/Technology Division
Bedford, Massachusetts 01730
10. PROGRAM ELEMENT NO.
2 AA 635
11. CONTRACT/GRANT NO.
68-02-1376 TO No. 27
12. SPONSORING AGENCY NAME AND ADDRESS
U.S. Environmental Protection Agency
Air Management Technology Branch
Monitoring and Data Analysis Division
Research Triangle Park, North Carolina 27711
13. TYPE OF REPORT AND PERIOD COVERED
Final Report
14. SPONSORING AGENCY CODE
200/04
15. SUPPLEMENTARY NOTES
16. ABSTRACT
Relationships between traffic, vehicle emissions, and carbon monoxide (CO) levels
within the Washington, D.C., area are analyzed using the revised CO Hot Spot Guide-
lines and supplementary computer models. As such, the report provides a demonstration
of the revised CO Hot Spot Guidelines, as well as a first level analysis of potential
CO problems in the Washington, D.C. area. Three levels of analysis are described:
(1) areawide screening of all signalized intersections, (2) hot spot verification at
29 selected locations, and (3) comparison of computer modeling results with ambient
data. Data requirements and resource needs are identified for each level of analysis.
Annotated instruction sheets, in addition to all tables and graphs used in the cal-
culations, are provided.
A preliminary review of the data revealed that the existing data base for the Washingtor
D.C., area was inadequate for developing and testing techniques for relating changes
in VMT and/or vehicle emissions to changes in ambient CO levels.
17.
KEY WORDS AND DOCUMENT ANALYSIS
DESCRIPTORS
b.lDENTIFIERS/OPEN ENDED TERMS C. COSATI F'ield/Group
Carbon Monoxide
CO Hot Spots
Hot Spot Guidelines
Washington, D.C.
Air Quality
18. DISTRIBUTION STATEMENT
Distribution Unlimited
19. SECURITY CLASS (This Report)
Unclassified
21. NO. OF PAGES
144
20. SECURITY CLASS (Thispage)
Unclassified
22. PRICE
EPA form 2220-1 (R«v. 4-77) PREVIOUS EDITION is OBSOLETE
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