EPA-901 /9-76-001 GCA-TR-75-35-G(l)
GUIDELINES FOR IDENTIFICATION
AND EVALUATION OF LOCALIZED
VIOLATIONS OF CARBON
MONOXIDE STANDARDS
FINAL GUIDELINE REPORT
Contract No. 68-02-1337
Task Order No. 6
Prepared For
U.S. ENVIRONMENTAL PROTECTION AGENCY
Region I Office
Boston, Massachusetts
January 1976
GCA/TECHNOLOGY DIVISION
BEDFORD, MASSACHUSETTS 01730
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EPA-901/9-76-001 GCA-TR-75-35-G(l)
GUIDELINES FOR
IDENTIFICATION AND EVALUATION OF
LOCALIZED VIOLATIONS OF CARBON
MONOXIDE STANDARDS
Final Guideline Report
by
Theodore P. Midurski
Alan H. CasCaline
David A. Bryant, Project Director
GCA CORPORATION
GCA/TECHNOLOGY DIVISION
Bedford, Massachusetts
January 1976
Contract No. 68-02-1337
Task Order No. 6
EPA Project Officer
John Calcagni
Air Branch, Region I
U.S. ENVIRONMENTAL PROTECTION AGENCY
Region I Office
Boston, Massachusetts
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This report was furnished to the U.S. Environmental Protection Agency by the
GCA Corporation, GCA/Technology Division, Bedford, Massachusetts 01730, in
fulfillment of Contract No. 68-02-1337, Task Order No. 6. The opinions, find-
ings, and conclusions expressed are those of the authors and not necessarily
those of the U.S. Environmental Protection Agency or of the cooperating agencies.
Mention of company or product names is not to be considered as an endorsement by
the U.S. Environmental Protection Agency.
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ABSTRACT
This report presents guidelines for the identification and evaluation of
localized violations of carbon monoxide air quality standards in the
vicinity of streets and highways. The guidelines are provided to facil-
itate the rapid and efficient review of CO conditions along existing
roadway networks, without the need for extensive air quality monitoring,
and are based upon the use of limited traffic data. Two stages of review
are provided for. Preliminary screening, performed with simple nomographs
included herein, simply identifies those locations with the potential to
violate CO standards; no quantitative estimate of CO concentrations results
from preliminary screening. Verification screening, using procedures and
forms provided herein, allows for consideration of additional site-specific
conditions and provides quantitative estimates of maximum CO concentrations.
Both screening procedures are performed manually and are based upon the
EPA Indirect Source Review Guidelines. Data collection procedures, com-
putation techniques, and forms are recommended, and examples are provided.
ill
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CONTENTS
Page
Abstract iii
List of Figures vi
List of Tables ix
Acknowledgments x
Sections
I Introduction 1
Purpose 1
Overview of the Process for Control of Hot Spots 2
How to Use These Guidelines 7
Basis for the Procedures 8
References 14
II Task 1 - Preliminary Screening 15
Introduction 15
Overview of the Preliminary Screening Process 17
Detailed Instructions for Preliminary Screening 51
References 59
III Task 2 - Hot Spot Verification 60
Introduction 60
Overview of Hot Spot Verification 61
iv
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CONTENTS (continued)
Sections Page
Detailed Instructions for Performing Hot Spot
Verification 90
References 99
IV Additional Screening Instructions 100
G/Cy 100
Local Vehicle Mix Correction Factor 103
Reasonable Receptor Site 105
Cruise Speed 108
Capacity 109
8-Hour Correlation Factor 111
Background Concentration 112
Definitions 113
Appendix
A Base Maps Developed for the Screening of Waltham,
Massachusetts A-l
B Examples of the Preliminary Screening Procedure B-l
C Examples of the Hot Spot Verification Procedure C-l
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FIGURES
No. Page
1 Decision-Making Process for Selection of CO Control
Measures 3
2 Critical Volumes at Signalized Intersections. Analysis
of a 2-Lane 2-Way Street in a Congested Area 21
3 Critical Volumes at Signalized Intersections. Analysis
of a 2-Lane 2-Way Street in a "Noncongensted Area 22
4 Critical Volumes at Signalized Intersections. Analysis
of a 3-Lane 2-Way Street in a Congested Area 23
5 Critical Volumes at Signalized Intersections. Analysis
of a 3-Lane 2-Way Street in a Noncongested Area 24
6 Critical Volumes at Signalized Intersections. Analysis
of a 4-Lane 2-Way Street in a Congested Area 25
7 Critical Volumes at Signalized Intersections. Analysis
of a 4-Lane 2-Way Street in a Noncongested Area 26
8 Critical Volumes at Signalized Intersections." 'Analysis
of a 3-Lane 1-Way Street 27
9 Critical Volumes at Signalized Intersections. Analysis
of a 2-Lane 1-Way Street 28
10 Critical Volumes for Uninterrupted Flow Conditions.
Analysis of Controlled Access Facilities 30
11 Critical Volumes for Uninterrupted Flow Conditions.
Analysis of Uncontrolled Access Facilities 31
12 Critical Volumes at Nonsignalized Intersections. Analysis
of a 2-Lane, 2-Way Major and Minor Street Intersection-
Under 4-Way STOP-Sign Control in a Congested Area 34
vi
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FIGURES (continued)
No.
13 Critical Volumes at Nonsignalized Intersections. Analysis
of a 2-Lane, 2-Way Major and Minor Street Intersection
Under 4-Way STOP-Sign Control in a Noncongested Area 35
14 Critical Volumes at Nonsignalized Intersections. Analysis
of a 2-Lane, 2-Way Minor Street Intersecting a 2-Lane,
2-Way or 2-Lane, 1-Way Major Street in a Congested Area 36
15 Critical Volumes at Nonsignalized Intersections. Analysis
of a 2-Lane, 2-Way Minor Street Intersecting a 2-Lane,
2-Way or 2-Lane, 1-Way Major Street in a Noncongested Area 37
16 Critical Volumes at Nonsignalized Intersections. Analysis
of a 2-Lane, 2-Way Minor Street Intersecting a 4-Lane,
2-Way Major Street in a Congested Area 38
17 Critical Volumes at Nonsignalized Intersections. Analysis
of a 2-Lane, 2-Way Minor Street Intersecting a 4-Lane,
2-Way Major Street in a Noncongested Area 39
18 Critical Volumes at Nonsignalized Intersections. Analysis
of a 4-Lane, 2-Way Minor Street Intersecting a 4-Lane,
2-Way Major Street in a Congested Area 40
19 Critical Volumes at Nonsignalized Intersections. Analysis
of a 4-Lane, 2-Way Minor Street Intersecting a 4-Lane,
2-Way Major Street in a Noncongested Area 41
20 Critical Volumes at Nonsignalized Intersections. Analysis
of a 2-Lane, 1-Way Minor Street Intersecting a 2-Lane,
2-Way or 2-Lane, 1-Way Major Street 42
21 Critical Volumes at Nonsignalized Intersections. Analysis
of a 2-Lane, 1-Way Minor Street Intersecting a 4-Lane,
2-Way Major Street • 43
22 Process Flow Diagram for the Preliminary Screening of
Carbon Monoxide Hot Spots 49
23 Maximum Impact of Traffic In an Approach Lane Upstream From
a Signalized Intersection at a Receptor Site Located at a
Perpendicular Distance of 10 Meters, 1977 67
vii
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FIGURES (continued)
No.
Page
24 Maximum Impact of Traffic in a Lane Downstream From an
Intersection at a Receptor Site Located a Perpendicular
Distance of 10 Meters Away, 1977 68
25 Relative Concentration of CO Versus Perpendicular Distance
From a Traffic Lane Near a Signalized Intersection 69
26 Volume Demand - Capacity Ratio in a Freeway or Expressway
Lane Versus CO Concentration Impact at a Perpendicular
Distance of 10 Meters, 1977 70
27 Volume Demand - Capacity Ratio in a Lane on a Major Street
Versus CO Concentration Impact at a Perpendicular Distance
of 10 Meters, 1977 71
28 Relative Concentration of CO Versus Perpendicular Distance
From a Traffic Lane With Freely Flowing Traffic 72
29 Impact of Traffic Upstream From a Nonsignalized Intersection
on CO Concentrations at a Receptor Site Located a Perpen-
dicular Distance of 10 Meters Away, 1977 74
30 Relative Concentration of CO Versus Perpendicular Distance
From a Traffic Lane Near a Nonsignalized Intersection 75
31 Process flow Diagram for the Hot Spot Verification
Procedure 88
viii
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TABLES
No. Page
1 Criteria for Selection of Cruise Speed Values 108
ix
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ACKNOWLEDGMENTS
Numerous individuals and several organizations have been helpful in
carrying out the work presented in this report. For these contributions
GCA/Technology Division extends its sincere gratitude.
Project direction and technical guidance were given by the Project Officer,
Mr. John Calcagni of Region I, and by Mr. Gary Hawthorne and Mr. Jerry
Kurtzweg of the Office of Transportation and Land Use Policy, U.S. Environ-
mental Protection Agency.
Several state and local agencies supplied information and other assistance
for this work. Particular thanks go to the Bureau of Transportation
Planning and Development of the Massachusetts Department of Public Works,
the City of Waltham, Massachusetts, and the Office of Air Quality Planning
and Standards of the U.S. Environmental Protection Agency.
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SECTION I
INTRODUCTION
A. PURPOSE
This volume presents a set of guidelines for the identification and anal-
ysis of locations with the potential for experiencing violations of the
National Ambient Air Quality Standard for carbon monoxide. These guide-
lines are intended for engineers, planners, and other officials who must
consider the effects on air quality of certain traffic management decisions
and whose responsibility includes traffic planning to control CO "hot
spots." These guidelines are designed to identify potential carbon mono-
xide hot spots, using only data on automobile traffic and thus avoiding
the need for time-consuming and costly monitoring of air quality at every
potential hot spot.
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B. OVERVIEW OF THE PROCESS FOR CONTROL OF HOT SPOTS
1. General
Controlling CO hot spots requires several steps: identification of the
potential hot spots, detailed analysis of each hot spot, and selection of
control measures. Although this document is primarily concerned with
identification and analysis of carbon monoxide problem areas, it is well
to bear in mind that the ultimate purpose of these procedures is to allow
the selection of suitable control measures to insure that public health
will be protected, by complying with the National Ambient Air Quality
Standards. To that end, the following text presents a brief overview of
the entire process of controlling hot spots, from identification to
implementation of control measures.
Choosing among alternative traffic measures for control of CO hot spots
will be much like many other public investment decisions. One must bal-
ance the benefits and costs and choose accordingly. When meeting air
quality standards is one of the goals, the nature of the choice is some-
what altered, however, because attainment of the specified standard is
necessary to protect public health. Consequently, meeting air quality
standards will be the first consideration when selecting among alterna-
tive actions for control of hot spots. Once that criterion has been
satisfied, then the choice among alternatives can be made on the basis of
costs and other issues, as with other public investments.
2. Recommended Process
Figure 1 is a flow diagram for the overall process for selection of CO
control measures. Each of the numbered steps will be briefly described
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0
PRELIMINARY
SCREENING
VERIFICATION
SCREENING
DETAILED
MODELING
IDENTIFICATION OF
ALTERNATIVE
IMPROVEMENTS
EVALUATION OF
ALTERNATIVES
SELECTION OF
CONTROL MEASURES
IMPLEMENTATION
EVALUATION
AVAILABLE TRAFFIC DATA
LIMITED ADDITIONAL
TRAFFIC DATA
COLLECT NEW
TRAFFIC DATA,
AIR QUALITY DATA,
METEOROLOGICAL DATA
OBTAIN
TRANSPORTATION
PLANNING DATA
AIR QUALITY EFFECTS
SOCIAL, ECONOMIC
INSTITUTIONAL,OTHER
EFFECTS
Figure 1. Decision-making process for selection
of CO control measures
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a. Step 1: Preliminary Screening - Preliminary screening of roadways
and intersections to identify possible CO hot spots'is the first task.
Preliminary screening procedures, presented in Section II of this volume,
use generalized procedures and a minimum amount of traffic data; available
data can be used in most cases. To facilitate the rapid screening of
many locations, simple charts and nomographs are provided. The output
is simply the identification of potential hot spots; no quantitative
estimates of CO concentrations are produced.
b. Step 2: Verification Screening - Verification screening is a more
detailed manual analysis of locations that are shown by preliminary screen-
ing to be potential hot spots. Verification screening uses a larger
amount of site-specific data than does preliminary screening, and produces
quantitative estimates of CO levels. New traffic data will be needed in
many instances. Section III of this volume describes the procedures for
verification screening.
c. Step 3: Detailed Modeling - Once the hot spots are identified, they
are analyzed with detailed analytical models (usually some form of com-
puter model) using procedures described elsewhere in the literature or,
in some cases, using the detailed procedures for verifying hot spot
potential as described in Sections III and IV. Modeling provides the
base case against which alternatives are judged. Modeling generally
requires the collection of new data on traffic, air quality, and meteor-
ology. Modeling reveals the degree of emission reduction that is needed
from traffic controls. A variety of models are available, some from EPA and
DOT and others from the private sector. Model selection will not be
described here but must be tailored to the individual site in question.
d. Step 4: Identification of Alternative Improvements - Knowing the
amount of CO emissions reduction that is needed, the planner can begin
to narrow the choice of control measures by identifying those alternatives
that appear capable of meeting the air quality requirements. New (or
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existing) transportation planning data are obtained at this point,
to allow forecasting emissions in future years and to allow consideration
of macroscale traffic changes when necessary. The alternatives to be
evaluated should be capable of achieving the NAAQS at each hot spot,
after accounting for "tail pipe" controls such as new vehicle pollution
control devices.
e. Step 5: Evaluation of Alternatives - Evaluation of air quality ef-
fects uses the models from Step 3 and determines if the NAAQS would be
met. For those alternative measures that would satisfy the air quality
criteria (only), the other effects are then identified and quantified.
If the alternative control measures are inadequate, or if it is prudent
to examine additional alternatives because of implementation obstacles
that may arise, the process would revert to Step 4 at this point.
f. Step 6: Selection of Control Measures - Selecting among the alternative
measures requires balancing the non-air quality effects (assuming that
only those measures that will achieve NAAQS are being considered at
this point). The thrust of the choice is to minimize the adverse impacts.
Often, however, the choice will require weighing effects of various types.
For example, the decision might be between two control measures that
are similar except that one requires more capital outlay but is more
beneficial to fuel consumption. Such choices are commonly made in trans-
portation facility planning. This Guideline cannot detail how to make
such choices; an excellent summary of the process has recently been pub-
lished and includes a recommended procedure for considering nonmonetary
costs and benefits.
g. Step 7: Implementation - Having selected a measure, it must be im-
plemented. When planning measures, the time to accomplish this step
should be considered in all analyses of effectiveness.
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h. Step 8: Evaluation - After implementation, the traffic and air
quality should be monitored and calculations made to determine if NAAQS
will be met. Rarely are planning predictions exact; in some cases it
will be necessary to adjust the control measures, or supplement them,
in order to (1) meet air quality goals or (2) ameliorate unexpected
impacts.
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C. HOW TO USE THESE GUIDELINES
As described above, there are two screening tasks for which procedures
are provided in this volume. The sequence of using this volume for
screening is to first become familiar with this guideline, then to use
the procedures in Section II for a preliminary screening of all important
intersections and midblock locations. The preliminary screening provides
a yes/no determination; those locations identified as possible hot spots
are then analyzed in more detail, using the verification procedures in
Section III. Sections II and III provide step-by-step instructions and
supply all necessary charts and computation forms.. Section IV provides
more detailed information that is necessary for both screening tasks.
Appendix A provides maps of Waltham, Massachusetts, to illustrate the
type of traffic flow maps that will be needed for screening. Appendixes B
and C provide examples of the preliminary screening and verification pro-
cedures, respectively, using locations in Waltham and include location
sketches that show that type of physical detail needed for using these
procedures. The three appendixes should be helpful when first using these
guidelines, as illustrations of the procedures.
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D. BASIS FOR THE PROCEDURES
1. Previous Method as the Basis
Both the preliminary screening procedures and the verification screening
procedures presented in this report are based upon a technique previously
developed for determination of carbon monoxide concentrations near facil-
ities such as major shopping centers. The technique is referred to as the
Indirect Source Review Guideline and is described in an earlier EPA
2
report.
Before using these procedures, it is well to understand their technical
basis in order to recognize their assumptions and limitations. The fol-
lowing is a discussion of the technical basis for the procedures, begin-
ning with a brief explanation of the key factors influencing CO
concentrations.
2. Nature of Carbon Monoxide
On or adjacent to streets or highways, the primary contributor to carbon
monoxide (CO) concentrations is automotive traffic on the nearby road-
ways. The highest concentrations of CO have been found to occur near
intersections, where vehicle speeds are generally quite low and where
acceleration, deceleration, and idling occur; these types of vehicle
operating modes tend to produce high rates of carbon monoxide emissions.
The actual concentration of CO at a particular location is the sum of
(1) concentrations attributable to traffic in the immediate vicinity and
(2) background concentrations attributable to more remote sources of CO.
In most instances where CO levels are higher than allowed by the National
Ambient Air Quality Standard (NAAQS), it has been found that the contribu-
tion from nearby sources is substantially more important than the back-
ground. Consequently the procedures used in this document focus on
calculation of the concentrations from nearby sources, and simply add
a measured or assumed background concentration.
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The concentration of carbon monoxide attributable to nearby sources can
be expressed as follows:
C = V ' E • K • i (1)
s
where C = concentration of CO at a particular location
V = traffic volume (in vehicles/hour, say)
E = average emissions rate (in grams/hour, say), which
is a function of vehicle types, speeds, and age.
K = proportionality factor that accounts for the
geometry of the situation, including wind direction
and distance from roadway to receptor location.
S = wind speed
It can be seen from equation (1) that, at a given location, carbon monox-
ide concentrations are directly proportional to traffic volume and
inversely proportional to wind speed. The emissions rate, E, is highest
when vehicle speeds are low, such as when volumes are highest. Thus, the
highest CO concentrations will tend to occur when traffic volumes are
the highest and when wind speeds are low.
The NAAQS for carbon monoxide specifies two limits. First, there is a
limit of 35 parts per million (p.pm) for a 1-hour average concentration.
Second, there is a limit of 9 ppm for an 8-hour average concentration.
The NAAQS specifies that each of these limits may be exceeded only once
per year. Thus, the process of screening for hot spots must be designed
to examine the highest concentrations likely to occur in a year.
3. Basis for the Screening Procedures
In developing the screening procedures, a distinction was made between
(1) the factors that influence CO levels and are site-specific and (2)
the factors that do not vary significantly from one site to another.
Of the factors mentioned above, the highly site-specific elements are
traffic volume (V), vehicle speeds (included in E), and the distance
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from the roadway to the site being evaluated (part of K). Each of these
is thus determined separately for each location to be screened. Several
other factors are common to a given state or metropolitan area, and are
determined just once for each screening program, namely the emission fac-
tors (determined by the local vehicle mix and included in E). The remain-
ing factors relate to meteorology, namely wind speed (S) and direction
(which is included in K).
In a given metropolitan area, conditions of low wind speed occur with a
predictable frequency; the frequency of such occurrences does not vary
substantially among the various geographic locations in an area. Con-
sequently, the procedure presented in the Indirect Source Guideline and
used here has a standard low wind speed (1 meter/sec or 2 mph) that is
used for all locations. As for wind direction, the procedure assumes
that the wind is at an angle to the roadway that tends to produce the
highest concentrations of CO. This assumption eliminates the need to
analyze seasonal wind direction frequencies separately for each inter-
section or midblock location to be analyzed. This assumption is reason-
able, because any given location will tend to experience every wind angle
during a year.
In summary, the screening procedure uses (1) a standardized set of meteor-
ological conditions, (2) a regional set of emission factors, and (3) data
on traffic volumes, traffic speeds, and distance from roadway to receptor
specific for each site to be analyzed.
4. Limitations of the Procedure
The purpose of the screening procedure is to efficiently identify loca-
tions with the potential for violation of the NAAQS for carbon monoxide.
In order to achieve an efficient process, it was necessary to make a
number of simplifying assumptions, several of which have already been
mentioned. Where such assumptions were made and where generalized condi-
tions or relationships were included, it was necessary to be conservative;
10
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that is, it was desirable to overpredict CO levels rather than under-
predict them, in order to insure that potential hot spots would not be
missed. Each succeeding stage of analysis has fewer assumptions, however.
Preliminary screening requires the least effort per site and thus has the
greatest number of simplifying assumptions. Verification screening allows
a greater number of localized adjustments and thus can be more accurate,
requires greater effort per site, but need only be performed for sites
shown by preliminary screening to be potential hot spots. Modeling, not
presented in this volume, requires the greatest effort for each site but
potentially is most flexible and accurate.
a. Meteorological Assumptions - The wind conditions used in this volume
2
are identical with those in the EPA Indirect Source Review Guideline.
There are no provisions for adjustments here, although there are techniques
described in Reference 2 for compensating for different wind speeds. To
illustrate the reasonableness of the assumed conditions, data for Boston
were examined. In the winters of 1967 to 1972, wind speeds were between
0 and 3 mph (i.e., in the range assumed here) during more than 2 percent
of the time. (Recall that the hot spot guideline is intended to find
the peak likely CO level,.which would be representative of the second-
worst hour and thus would be exceeded less than 0.1 percent of the time.)
Another meteorological factor is ambient temperature. Inasmuch as the
peak CO concentrations usually occur in the winter, at least in the
Northeastern U.S. where these screening procedures will first be applied,
an ambient temperature of 0 C (32 F), is assumed. This differs from the
Indirect Source Review Guidelines which uses 68°F-86°F, judged to be
reasonable for that application. Colder temperatures produce higher
emission rates, and temperatures lower than 0°C are certainly not uncommon.
As an example, the mean daily average temperature in Boston is 30°F in
Atmospheric stability consistent with the assumptions herein, also.
11
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January and February, which indicates there are many hours with tempera-
tures below the assumed 32°F; also there are 94 days per year in Boston
during which the minimum temperature is 32°F or below. Thus, the
assumed condition of 0 C is reasonable but not particularly conservative.
b. Traffic Assumptions - The screening technique herein is designed for
a minimum of effort. To minimize the need for collection of special
traffic data, the preliminary screening is based upon using average daily
traffic (ADT), a statistic that is normally available for all major roads,
rather than using hourly data. Hourly traffic must be used for calculat-
ing CO concentrations, however, so the preliminary .screening procedure
incorporates the following assumptions that relate ADT to hourly travel
volumes:
o Peak hour traffic represents 8.5 percent of the ADT.
9 The directional split on two-way facilities during the
peak hour is about 40 percent to 60 percent at mid-
block .locations and 50 percent to 50 percent at intersections.
9 For multi-lane facilities, the volume on the outside lanes
(towards the shoulder) is generally lower than the inner
lane volumes.
Again, each of these assumptions is judged to be .reasonable for the pur-
pose of preliminary screening. As for verification screening, there .is
a provision for determining actual hourly volumes. In both cases, there
are additional assumptions regarding signal operations and speed-volume-
capacity relationships, which are discussed further in Sections II, III,
and IV and in Reference 2.
Also, at present there are no correction factors available for ambient
tempreatures below 0°C.
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c. Assumed Conditions - The data provided here for screening is based upon
the 1977-1978 winter period; that is, the assumed vehicle population has
the emission characteristics of that time. This date was chosen because
it will be the first winter after the present statutory deadline of June,
1977, for meeting CO standards everywhere in the U.S. Note, however, that
the curves provided here for preliminary screening to not include
inspection/maintenance programs or other "tail pipe" controls, because
not all areas will have them in effect. The verification screening
procedures do allow for such tail pipe control measures to be accounted
for.
d. General Comments - The procedures described herein embody a number
of simplifying assumptions, the most important of which have been des-
cribed. Such simplifications are necessary for the screening process,
for otherwise the screening effort would be considerably greater. These
assumptions will apply more accurately to some locations than to others.
That is, the user should recognize that the assumed conditions will not
be representative of conditions at all locations. In general, the proce-
dures are intended to produce a reasonable estimate of peak CO concentra-
tions. When site-specific data could not be used, the assumed general
conditions were chosen to be conservative. This prevents overlooking hot
spots. Later stages of analysis can be more site-specific, less conserva-
tive, and thus more precise. In particular, the first-stage (preliminary)
screening is qualitative, and will only identify those sites with the
potential for violations of the NAAQS. The second-stage (verification)
screening allows some additional site-specific conditions to be considered,
and will be less conservative than preliminary screening, but still pro-
duces approximations of peak CO levels. The procedures are not intended
to replace more detailed modeling, especially for circumstances not con-
sistent with the assumptions.
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E. REFERENCES
1. Frye, F. F. Alternative Multimodal Passenger Transportation Systems,
Comparative Economic Analysis. Creighton Hamburg, Inc. For: High-
way Research Board, Washington, D.C. National Cooperative Highway
Research Program Report Number 146. 1973. p. 68.
2. .Guidelines for Air Quality Maintenance Planning and Analysis.
Volume 9: Evaluating Indirect Sources. U.S. Environmental Protection
Agency, Research Triangle Park, N.C. Publication No. EPA-450/4-75-001.
January 1975.
3. Climatic Atlas of the United States. U.S. Department of Commerce,
Environmental Science Services Administration. U.S. Government
Printing Office, Washington, D.C. pp. 2, 4, 24, 28. June 1968.
14
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SECTION II
TASK I - PRELIMINARY SCREENING
A. INTRODUCTION
Hot spot screening can be defined as the analysis of a highway network
in order to identify specific locations where carbon monoxide concentra-
tion may exceed National Ambient Air Quality Standards which specify
maximum ambient concentrations allowable under provisions of the Clean
Air Act. The purpose of the screening procedures developed herein is to
provide a practical, economical method of identifying locations where
appropriate action may be required to reduce ambient carbon monoxide con-
centrations. In this regard, appropriate action implies implementing any
of a number of plans or measures available for reducing carbon monoxide
emission levels.
On or adjacent to roadway networks, the primary source of carbon monoxide
is vehicular traffic using that network. The highest concentrations
typically occur in the vicinity of intersections where vehicle speeds are
generally quite low and acceleration, deceleration, and idling, occur.
This is not to say, however, that concentrations in the vicinity of freely
flowing traffic do not ever exceed air quality standards. The implication
intended is that any technique that is developed to identify possible
carbon monoxide hot spots, must focus on the entire street network in-
cluding intersections and midblock locations as well as expressways.
A technique has been developed that does permit analysis of intersections,
midblock locations, and expressways based on data developed by the U.S.
15
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Environmental Protection Agency and presented in a document entitled
Guidelines for Air Quality Maintenance Planning and Analysis, Volume_9_:
Evaluating Indirect Sources.1 This technique provides for separate anal-
yses of signalized intersections, nonsignalized intersections, midblock
sections of arterial streets, and expressways. The technique is presented
as two separate tasks - the first being the preliminary screening pro-
cedure which facilitates identifying potential locations where hot spots
may exist. This is accomplished using only the most basic traffic data
inputs and is intended to provide only a "go- no go" type of analysis;
in other words, it indicates only whether there is potential for a hot
spot to exist but does not attempt to quantify the'potential. The anal-
ysis is conducted utilizing a series of nomographs that express a rela-
tionship between certain roadway characteristics (physical and operational)
and expected "worst case" air quality. The second task involves verifying
the hot spot potential of a location by using more specific data regarding
that location, and established relationships (again, depicted by a series
of nomographs) between air quality and nearby traffic characteristics.
Instructions for performing both screening tasks are provided in this
document; initial screening is discussed in the remainder of this
Section while Section III.discusses the second-stage analysis procedure.
n
The terms Preliminary Screening and Initial Screening are used inter-
changeably throughout this document.
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B. OVERVIEW-OF THE PRELIMINARY SCREENING PROCESS
A description of the preliminary screening process must include discussions
of three elements critical to the process; these include (1) the data
required, (2) the nomographs that relate the roadway characteristics to
air quality, and (3) a set of standard forms on which the analysis is per-
formed and the results reported. Each of these elements will be described
below.
1. Data Requirements^
The entire preliminary screening task may be possible to complete for
many communities with only a minimal field data collection effort. Data
required includes areawide traffic volume data and a street inventory of
sufficient detail to indicate the lane composition (use and number of
lanes), traffic control utilized (mainly, the locations of signalized
intersections are of primary importance), and whether various streets
operate one-way or two-way. Also, additional backup data are required
in order to estimate the lane capacity of arterial streets and expressways,
as will be mentioned later.
a. Traffic Volume Data - Traffic volume data should be summarized in the
form of a traffic flow map indicating the highest monthly average daily
traffic (ADT) volumes for the winter season, projected to the year 1977.
Volume data need not be developed for every street on the network; of
primary interest should be: (1) those streets and highways on the Federal
Aid System, (2) those not on the Federal Aid System but which are con-
trolled by traffic signals; and (3) those not on the Federal Aid System
but which are considered by local officials to be "important" or high
volume facilities.
Traffic volume data is perhaps the most abundant data element available
concerning a highway network. The intent here is that existing data be
17
-------
used wherever possible, implying that existing volume data should be
available in most instances to develop a suitable traffic flow map. *n
many communities where traffic studies or transportation plans have been
developed, flow maps may already be available, requiring only minimal
updating. As an example, a traffic flow map for the City of Waltham,
Massachusetts (see Appendix A, Figures A-3a and A-3b) was developed with
only minimal effort utilizing an existing flow map extracted from an
Areawide TOPICS (Traffic Operations Program to Increase Capacity and
Safety) Plan. Development of flow maps, however, should be carefully
guided by cognizant state highway and transportation planning officials.
b. Highway Inventory Data - Highway inventories are normally available
from state transportation, planning or highway departments. These in-
ventories should be made available for each community where hot spots
are being investigated. The required data that can be obtained from
these inventories include descriptions of operational characteristics
of the roadways (e.g., one-way or two-way operation); information regard-
ing the number of lanes, use of medians, functional classification, etc.,
and occasionally, volume data. Also, data must be obtained regarding
intersectional traffic control, particularly the locations where traffic
signals are utilized. It is helpful if the locations of all signalized
intersections are plotted on a base map.
c. General Backup Data - Other data elements are required which may not
be available from previous studies or from existing inventories. Included
is information required to estimate the lane capacity of streets on the
network, mainly, estimates of truck factors, knowledge of conditions such
as restricted lateral clearances, severe terrain features, etc. This
information can be obtained through local planning or engineering per-
sonnel and by field reconnaissance. For a comprehensive discussion of
roadway lane capacity, the reader is referred to the Highway Research
o
Board's Special Report No. 87, the 1965 Highway Capacity Manual.
18
-------
2. Nomographs for Preliminary Screening
The nomographs for preliminary screening provide the basic tool for re-
lating various traffic and roadway characteristics to hot spot potential.
In particular, these nomographs relate a roadway's average daily volume
demand and capacity characteristics to potential for exceeding the
National Ambient Air Quality Standard for 8-hour average concentrations
of carbon monoxide (9.0 parts per million). Separate sets of nomographs
are presented for three distinct types of analysis including signalized
intersections, nonsignalized intersections, and for conditions where
uninterrupted flow prevails. Each of these sets is discussed below.
a. Signalized Intersections - Eight separate nomographs are presented.
Each of the nomographs was developed for screening intersection legs of
a particular configuration (e.g., the nomographs presented in Figure 2
was developed to screen 2-lane, 2-way intersection legs in congested
areas while Figure 5 presents a nomograph developed for screening 3-lane,
2-way legs in noncongested areas). Included are nomographs developed for
screening the following leg configurations:
• 2-lane, 2-way (congested area)
• 2-lane, 2-way (noncongested area)
• 3-lane, 2-way (congested area)
a 3-lane, 2-way (noncongested area)
• 4-lane, 2-way (congested area)
• A-lane, 2-way (noncongested area)
o 3-lane, 1-way
• 2-lane, 1-way
A series of five curves appears on each nomograph. Each of these curves
represents a particular configuration of the cross street (with respect
to the leg being screened). Curves representing the following cross
street configurations are plotted on each nomograph:
19
-------
a 2-lane, 1-way
• 2-lane, 2-way
« 3-lane, 1-way
» 3-lane, 2-way
» 4-lane, 2-way
These are represented by curves A through E, respectively.
Each of the curves is a plot of the ADT on the intersection leg under
analysis (abscissa) versus the ADT on the cross street (ordinate) .
Each point on any of the curves, then, represents that combination of
traffic volumes (on the street under analysis and the cross street) which,
under certain assumed conditions, would result in ambient carbon monoxide
concentrations at cr very close to the maximum level permitted by the
National Ambient Air Quality Standard for 8-hour average concentrations
(9.0 ppm). This is to say that for any particular configuration of
street (under analysis) and cross street, if their respective ADT's are
plotted on the nomograph and the point plotted falls on or above the
(cross street) curve, the implication is that resulting carbon monoxide
concentrations are potentially in the vicinity of 9.0 ppm or more, indi-
cating that the leg lias hot spot potential. Plotting the ADT's (for
winter 1977-78) in this manner and noting where the plot lies with re-
spect to the cross street curve, is essentially the entire procedure
involved for using the nomographs. The appropriate nomograph is selected
based on the configuration of the leg being analyzed while selection of
the appropriate curve on the nomograph is based on the cross street
configuration.
1. Nomographs for Screening Signalized Intersections - Following are
the eight nomographs to be used for the preliminary screening of signalized
intersections (Figures 2 through 9).
20
-------
24
20
16
Ul
U)
K
CO
CO
o
or
O
H
O
12
CURVE
A
B
C
D
E
LEGEND
CROSS STREET
CONFIGURATION
2 lone
2 lone
3 lone
3 lone
4 lone
I way
2 way
I way
2 way
2 way
8
12
16
ADT ON STREET UNDER ANALYSIS: 2 lane-2 way ( CONGESTED AREA )
( in thousands of vehicles)
Figure 2. Critical volumes at signalized intersections,
2-lane 2-way street in a congested area.
Analysis of a
21
-------
UJ
LiJ
tr
O
cc
o
LEGEND
CROSS STREET
CONFIGURATION
2 lane - I way
2 lane -
3 lane
3 lone -
4 lane
ADT ON STREET UNDER ANALYSIS : 2 lane - 2 way (NON-CONGESTED AREA)
( m thousands of vehicles )
Figure 3. Critical volumes at signalized intersections,
2-lane 2-way street in a noncongested area.
Analysis of a
22
-------
§
o 2
Q c
< L-
CROSS STREET
CONFIGURATION
2 lone
2 lane
3 loni
3 lane
4 lone
I way
2 way
I way
2 way
2 way
ADT ON STREET UNDER ANALYSIS : 3 lane - 2 way (CONGESTED AREA)
( in thousands of vehicles )
Figure 4. Critical volumes at signalized intersections,
3-lane 2-way street in a congested area.
Analysis of a
23
-------
24
20
CURVE
A
B
C
D
E
LEGEND
CROSS STREET
CONFIGURATION
2 lone
2 lone
3 lone
3 lane
4 lane
I way
2 way
I way
2 way
2 way
16
LJ
UJ
c:
12
co
01 ^
g
o 12
4 -
I 1
8
16
ADT ON STREET 'UNDER ANALYSIS : 3 lone - 2 way (NON-CONGESTED AREA )
( in thousands of vehicles)
Figure 5. Critical volumes at signalized intersections,
3-lane 2-way street in a noncongested area.
Analysis of a
24
-------
UJ —
CE .iJ
O
a:
o =
LEGEND
CROSS STREET
CURVE CONFIGURATION
2 lane
2 lane
3 lane
3 lane
4 lane
I way
2 way
I way
2 way
2 way
12
16
ADT ON STREET UNDER ANALYSIS 4 lone - 2 way (CONGESTED AREA)
( in thousands of vehicles )
Figure 6. Critical volumes at signalized intersections,
4-lane 2-way street in a congested area.
Analysis of a
25
-------
in °
O «
-------
24
LEGEND
20
CURVE
A
B
C
0
E
CROSS STREET
CONFIGURATION
2 lane
2 lane
3 lone
3 lane
4 lane
I way
2 way
I way
2 way
2 way
16
12
10 «-
00 O
2 "*
Q_ -o
o c
o
—, v>
12
16
ADT ON STREET UNDER ANALYSIS : 3 lone - I way
( in thousands of vehicles )
Figure 8. Critical volumes at signalized intersections,
Analysis of a 3-lane 1-way street.
27
-------
20
UJ OT
UJ ^
cc .y
I- -<=
en •—
(/} O
O „
CE X)
LEGEND
CROSS STREET
CURVE CONFIGURATION
A 2 lane - I way
B 2 lone - 2 way
C 3 lane - I way
0 3 lane -2 way
E 4 lane -2 way
16
12
8
12
16
ADT ON STREET UNDER ANALYSIS : 2 lone - I way
( in thousands of vehicles )
Figure 9. Critical volumes at signalized intersections,
Analysis of a 2-lane 1-way street.
28
-------
b. Uninterrupted Flow - Two types of locations are considered where
conditions of uninterrupted flow prevail - these include expressways
and arterial streets. One nomograph is presented for each of these two
facility-types, as shown by Figures 10 and 11.
Expressways are considered in the nomograph presented in Figure 10. Three
separate curves are plotted on this nomograph representing 4-lane, 6-lane,
and 8-lane expressways. These curves are plotted as lane capacity (ab-
scissa) versus ADT (ordinate). Each point on the curve represents that
combination of lane capacity and 24-hour volume which, under certain as-
sumed conditions, would result in nearby ambient carbon monoxide concen-
trations of approximately 9.0 ppia. The implication, again, is that for a
particular roadway configuration with a certain lane capacity, an ADT
equal to or in excess of the "cricital" ADT (shown by the curve on the
nomograph) indicates that the location may be a potential hot spot.
The curves in Figure 11 indicate the critical ADT for various configura-
tions of arterial streets. Again, if the actual ADT (estimated for winter
1977-78) exceeds the "critical" ADT, hot spot potential is indicated.
The procedure, then, for using either of the nomographs presented in
Figures 10 and 11 is to plot the facilities estimated lane capacity ver-
sus its ADT and observe where this plot lies with respect to the curve
corresponding to the facility's configuration - if the plot falls on or
above the curve, hot spot potential is indicated.
1. Nomographs for Screening Uninterrupted Flow - Nomographs for
screening expressways and arterials where conditions of uninterrupted
flow prevail are presented as Figures 10 and 11.
c. Nonsignalized Intersections - Ten separate nomographs have been de-
veloped for the preliminary screening of nonsignalized intersections.
These nomographs are utilized to screen intersection legs controlled by
29
-------
V)
—
o
!c
•o
c
o
in
<
o
o:
o
8-LANE EXPRESSWAY
6-LANE EXPRESSWAY
EXPRESSWAY-^
1000
1200
1400
1600
1800
2000
LANE CAPACITY (vph)
Figure 10. Critical volumes for uninterrupted flow conditions,
Analysis of controlled access facilities.
30
-------
30
6-LANE ARTERIAL-
in
o
in
c
o
CO
26
4-LANE ARTERIAL-
22
18
O
H
CE
O
14
2-LANE ARTERIAL
10
600
800
1000
1200
1400
1600
LANE CAPACITY ( vph )
Figure 11. Critical volumes for uninterrupted flow conditions.
Analysis of uncontrolled access facilities.
31
-------
STOP-signs only; the through street legs of a STOP-sign controlled inter-
section are screened utilizing the nomographs presented for uninterrupted
flow.
Several curves are plotted on each nomograph, representing the estimated
lane capacity of the major through street. Any point on each curve repre-
sents that combination of ADT on the street under analysis and ADT on
the major through street (whose lane capacity corresponds with that
indicated for the curve) that would result in ambient carbon monoxide
concentrations of approximately 9.0 ppm (assuming certain other condi-
tions prevail). Therefore, in order to use these riomographs three ele-
«
ments of data other than the configuration of each street leg must be
determined, including (1) the ADT (winter 1977-78) on the street under
analysis, (2) the ADT (winter 1977-78) on the major through street, and
(3) the estimated lane capacity of the major through street. If, then,
the ADT's are plotted and the point lies on or above the curve correspond-
ing to the lane capacity of the major leg, hot spot potential is indicated.
Selection of the nomograph is based on the configuration of both the STOP-
sign controlled street being analyzed and the major through street. Again,
the curve representing lane capacity is based nn the major through street's
lane capacity.
1. Nomographs for Screening Nonsignalized Intersections - Nomographs
were developed for the preliminary screening of the following STOP-sign
controlled street configurations:
« 2-lane, 2-way, 4-way STOP (congested area)
• 2-lane, 2-way, 4-way STOP (noncongested area)
• 2-lane, 2-way minor; 2-lane major (congested area)
• 2-lane, 2-way minor; 2-lane major (noncongested area)
• 2-lane, 2-way minor; 4-lane major (congested area)
• 2-lane, 2-way minor; 4-lane major (noncongested area)
• 4-lane, 2-way minor; 4-lane major (congested area)
• 4-lane, 2-way minor; 4-lane major (noncongested area)
32
-------
• 2-lane, 1-way minor; 2-lane major
• 2-lane, 1-way minor; 4-lane major
These are presented as Figures 12 through 21, respectively.
3. Preliminary Screening Forms
Presented below are standard forms to be used as work sheets and summary
sheets for performing preliminary screening, as well as for reporting the
screening of a community. Included are the following:
0 Initial Screening Summary Sheet Form 1
• Preliminary Screening Work Sheet -
Signalized Intersections Form 2
• Preliminary Screening Work Sheet -
Uninterrupted Flow Form 3
• Preliminary Screening Work Sheet -
Nonsignalized Intersections Form 4
Each of these forms will be discussed briefly in the following text.
a. Initial Screening Summary Sheet (Form 1) - This form, as its name
implies, is intended to be used for summarizing the initial screening ef-
fort for a community. The information to be entered on the sheet includes
1. A description of each location analyzed - Broadway at
Park Street, or Vasser Street between Parson's Road
and Kennelworth Drive, for example.
2. The type of location analyzed - either signalized
intersection, nonsignalized intersection, freely
flowing arterial section, or expressway.
3. Whether or not hot spot potential is indicated by
the analysis.
The locations listed are then numbered sequentially. A completed example
Initial Screening Summary Sheet is provided on page B-2 of Appendix B.
33
-------
o
5
CvJ
I
g o
CJ
I-
Ld
UJ
CC
in
in
O
QC
O
z
O
C
o
3
O
.C
12.5
10.0
7.5
5.0
2.5
4 WAY STOP
LANE CAPACITY = 1200 vph
2.5
5.0
7.5
10.0
12.5
ADT ON STREET UNDER ANALYSIS : 2 lane - 2 way (CONGESTED AREA )
(in thousands of vehicles)
Figure 12. Critical volumes at nonsignalized intersections,
Analysis of a 2-lane, 2-way major and minor
street intersection under A-way STOP-sign con-
trol in a congested area.
34
-------
12.5
2.5
5.0
7.5
10.0
12.5
ADT ON STREET UNDER ANALYSIS : 2 lane - 2 way ( NON CONGESTED AREA )
(in thousands of vehicles )
Figure 13. Critical volumes at nonsignalized intersections.
Analysis of a 2-lane, 2-way major and minor
street intersection under 4-way STOP-sign con-
trol in a noncongested area.
35
-------
I
V
c
_o
CM
CM
LJ i:
CO _^
(T
O
-3
I-
Q
10.0
12.5
ADT ON CONTROLLED STREET : 2 lane - 2 way (CONGESTED AREA)
( in thousands of vehicles )
Figure 14. Critical volumes at nonsignalized intersections.
Analysis of a 2-lane, 2-way minor street inter-
secting a 2-lane, 2-way or 2-lane, 1-way major
street in a congested area.
36
-------
50
o
5
_o
CJ
t_
o ~»
§5
CJ "S
Q) •»-
c o
E CO
•o
CM C
.. o
til
UJ i:
H •£
tn —
cc
o
-5
z
o
40
30
20
10
2.5
5.0
7.5
10.0
12.5
ADT ON CONTROLLED STREET : 2 lane - 2 way {NON CONGESTED AREA )
( in thousands of vehicles)
Figure 15. Critical volumes at nonsignalized intersections.
Analysis of a 2-lane, 2-way minor street inter-
secting a 2-lane, 2-way or 2-lane, 1-way major street
in a noncongested area.
37
-------
100
2.5
7.5
10.0
12.5
ADT ON CONTROLLED STREET : 2 lane-2woy ( CONGESTED AREA )
( in thousands of vehicles)
Figure 16. Critical volumes at nonsignalized intersections.
Analysis of a 2-lane, 2-way minor street inter-
secting a 4-lane, 2-way major street in a con-
gested area.
38
-------
100
2.5
5.0
7.5
10.0
12.5
ADT ON CONTROLLED STREET : 2 lone-2 v/ay ( NON CONGESTED AREA)
(in thousands of vehicles)
Figure 17. Critical volumes at nonsignalized intersections,
Analysis of a 2-lane, 2-way minor street inter-
secting a 4-lane, 2-way major street in a non-
congested area.
39
-------
100
80
CM
i
c. tn
.E —
* '£ 60
.. 0)
LJ o
UJ
[— "°
CO §
Q- S 40
z
o
o 20
1
i£2?°*p/i
I
I
0 2.5 5.0 7.5 10.0 12.5
ADT ON CONTROLLED STREET : 4lones-2way (CONGESTED AREA)
( in thousands of vehicles )
Figure 18. Critical volumes at nonsignalized intersections.
Analysis of a 4-lane, 2-way minor street inter-
secting a 4-lane, 2-way major street in a con-
gested area.
40
-------
100
CM
I
-------
2.5
ADT ON CONTROLLED STREET : 2 lone - 1 way
(in thousands of vehicles)
12.5
Figure 20. Critical volumes at nonsignalized intersections.
Analysis of a 2-lane, 1-way minor street inter-
secting a 2-lane, 2-way or 2-lane, 1-way major street.
-------
100
7.5
10.0
12.5
ADT ON CONTROLLED STREET = 2 lane -I way
(in thousands of vehicles )
Figure 21. Critical volumes at nonsignalized intersections.
Analysis of a 2-lane, 1-way minor street inter-
secting a 4-lane, 2-way major street
-------
INITIAL SCREENING SUMMARY SHEET
page
of
City/Town:
State:
Analysis By:
Approved By:
(cttl.)
Date:
Date:
(titi.)
Location
Type
Hot Spot Indicated
or
Detailed Analysis Required
Yes
Form 1
44
No
-------
PRELIMINARY SCREENING WORK SHEET- SIGNALIZED INTERSECTIONS
page
City/Town:
State:
Analysis By:
Approved By:
(cm.)
(Cltl*)
.of
Date:
Date:
P*rt I Location:.
Part II Congested Area? Ye»:
No
.Part III Complex Intersection or Special Case? Yes; No; If yes, enter location on Initial Screening
Sumaary SKeet and proceed to next Intersection; It no, proceed with Part IV.
Part IV Analyze each leg separately on the form, below.
Le; under analysis
a
D» signal Ion
j^rr===— ==m^
b
Ad justed
AbT
(1977-78)
X
c
Conl i nur-
at ion
X
St rccc : Lrc:
d
AJ lu~Mi-d
APT
(1977-76)
e
OnllKiir-
£
Fir." re/
s_
Hot spot
Indicated?
<:• ,-t.or • Ld' •
Street: Itt:
h
Ad justed
A;;T
(1977-78)
i^
J.
Fig-re/
'ft
S-ro.'t: I..?-
Part I Location:.
Part II Congested Area?
No
Part III Coaplex Intersection or Special Case? Yes; No; If yes, enter location on Initial Screening
SuDciary Sheet and proceed to next Intersection; If no, proceed with Part IV.
P»rt 17 Analyse each leg seperately on the form, below.
Leg under Analysis
c
Desl^nJtlon
^I^===-~===^II^
b
Adjusted
ADT
(1977-78)
X
c
Conf i[;?l cd
APT
(1977-7K)
OnMjjur-
.1L Jon
(
Flcurp/
1L
Hot spot
SI riTl : 1 <••;:
St rtct : lea:
h
Ad |nst cd
Anr
(19,'7-/6)
^
ConlUnr-
at Ion
J.
FlKlTC/
curve used
V_
l!ot «pot
Inillcitrd?
S t I L' <• t : I .. p :
Form 2
-------
PRELIMINARY SCREENING WORK SHEET - UNINTERRUPTED FLOW
City/Town:
State:
Analysis By:
Approved By:
(del.)
page .of
Date: .
Date:
Facility
LOCAtlOO
Adjuated
ADT
(1977-78)
Configur-
a c ion
Eac.
lane
capacity
Hot Spot
Indicated
Form 3
46
-------
PRELIMINARY SCREENING WORK SHEET - NONSIGNALIZED INTERSECTIONS
page _
City/Town:
State:
Analysis By:
Approved By:
P«rt I Location!.
ttrt [I Analyia aach crot. street U| on the font, t»lo»t
.of
Date:
Date:
Through street data
a
Adjusted
ADI
(1977-78)
b
Configur-
ation
_c_
tit.
lane
capacity
^
Hot Spot
Indicated?
K
Street: Leg
e
Adjusted
ADT
(1977-78)
J_
Conf Igur-
JL
Figure/
£
Mot Spot
Street: Leg
i_
Adjuited
ADI
(1977-78)
J.
Configur-
ation
V_
Figure/
_1_
Hot Spot
Part I Location:_
•fart II Analyze each crosa itreet l«g on the forw, belov:
Through atreat data
a
Adjusted
ADT
(1977-78)
_b
Configur-
ation
_c_
Est.
lane
capacity
d^
Hot Spot
indicated?
M
Street: , Leg
e_
Adjuited
ADT
(1977-78)
f_
Conf igur-
A
Figure/
^
Hot Spot
Street: teg
J_
Adjusted
ADT
(1977-78)
J_
Configur-
ation
k^
Figure/
curve used
J.
Hot Spot
Indicated:
?«rt I Location:.
Fart 11 Analyze each crota «tre«t lag on the form, below;
Through street data
a
Adjusted
ADT
(1977-78)
b
Configur-
ation
c
Est.
lane
capocl ty
^
Hot Spot
Indicated?
Street: Leg
e_
Adjusted
ADT
(1977-78)
f
Configur-
ation
i
Figure/
curve used
Ji
Hot Spot
indicated?
Street: Leg
Adjuated
ADT
(1977-78)
1
Configur-
ation
^_
Figure/
curve used
-L
Hot Spot
indicated :
fare I Location:.
Hrl II Analyia each croaa street lag on th« for™, balov:
a
Adjuated
ADI
(1977-76)
b
Configur-
ation
Eat.
lane
capacity
i
Hot Spot
Indicated?
Minor crona atreet data
Street: l,eg
e
Adjusted
ADI
(1977-78)
£
Configur-
ation
i
Figure'
curve unrd
_h
Hot Spot
Indicated?
Street: Lef
l_
Adjusted
ADT
(1977-7S)
1
Conf Igur-
a t Ion
k.
Figure/
curva used
J.
Hot Spot
Indicated
Form 4
47
-------
b. Preliminary Screening Work Sheet - Signalized Intersections (Form 2) -
This form provides space for the analysis of two separate intersections.
To complete this form the intersecting streets' names are entered in
Part I and it is indicated whether or not the intersection is located in
a congested area, in Part II (guidance for making this determination is
provided in Section IV.H). In Part III, it is indicated whether or not
the location should be considered a complex intersection or a special case
(see Section IV.H for guidance in making this decision). For locations
that are not considered complex intersections or special cases, the actual
screening is performed in Part IV.
In Part IV each leg of the intersection is analyzed separately. Under
the main column heading "Leg Under Analysis," the leg designation (name
and orientation such as Amity Road, south leg), the adjusted average daily
traffic volumes, and the roadway configuration (for example, 4-lane,
2-way) are entered.
Under the other main column heading of "Cross-Street Data," the appropriate
data elements for the cross street leg having the highest traffic volume
are recorded. Then, utilizing the appropriate nomograph and curve, a
determination of hot spot potential is made and recorded. If the config-
uration of the other leg of the cross street is different from the leg
previously used in the. analysis, the procedure is repeated using the data
for the second cross-street leg and the appropriate nomograph and curve.
Note that columns f and j provide space to record the figure number and
curve designation for the nomograph used to perform the screening. Two
completed sample forms appear on pages B-4 and B-5 of Appendix B.
c. Preliminary Screening Work Sheet - Nonsignalized Intersections (Form 3)
This form allows for the analysis of four nonsignalized intersections. In
the first major column, "Through Street Data," the through street is
analyzed in the same fashion as for uninterrupted flow conditions. Each
leg of the controlled cross street is then analyzed in the two columns
under the heading of "Cross Street Data." A completed sample form is
provided on page B-6 of Appendix B.
48
-------
d. Preliminary Screening Work Sheet - Uninterrupted Flow (Form A) - Up to
30 locations where conditions of interrupted flow prevail can be analyzed
on each of these forms. The data required include the facility name; a
description of its location; its volume, configuration, and capacity;
and finally, whether or not hot spot potential is indicated. A sample
completed form is provided on page B-7 of Appendix B.
A . Performing Preliminary Screening
Detailed instructions on performing preliminary screening are provided in
Section II.C which follows. Prior to this detailed discussion it may be
helpful to look at the process in general terms; this can be best il-
lustrated by a flow diagram as shown in Figure 22.
As can be seen from the flow diagram, the first steps involve compiling
the required data. Once this has been completed, screening begins.
First, all signalized intersections are screened, followed by locations
where uninterrupted flow prevails, and finally, nonsignalized intersec-
tions. The importance, of the order of analysis becomes apparent in the
following detailed discussion.
49
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COUPILC TRAFFIC, ROADWAY
AND PLANKING DATA
DEVELOP/OBTAIN TRAFFIC
FLOW MAP FCfl 1977-78
OBTAIN LIST Of TRAFFIC SIGNAL
LOCATIONS, TOWNWIDE
DEVELOP/OBTAIN OTHER
GENERAL HOADWAY DATA
PERFORM PRELIMINARY SCREENING
OF EACH SIGNALIZED INTERSECTION
"USE NOMOGRAPt
,IN FIGURES 2
HS PROVIDED^
THRU 9 J
USE FORM Z
•C USE FORM I ~\
I'USE NOMOGRAPHS PROVIDE6N
"\l» FIGURES 10 AND II J
USE FORM I
USE NOMOGRAPHS PROVIDED
IN FIGURES 12 THRU Zl
USE FORM 4
TOLLOW UP WITH HOT
SF>OT VCRIFICATION
Figure 22. Process flow diagram for the preliminary screening
of carbon monoxide hot spots
50
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C. DETAILED INSTRUCTIONS FOR PRELIMINARY SCREENING
The following presents detailed instructions for performing preliminary
screening based on utilizing the data, nomographs, forms, and general
procedure discussed in the previous portion of this section. Included
are step-by-step instructions for the three subtasks (analysis of sig-
nalized intersections, uninterrupted flow, and nonsignalized intersec-
tions) involved in the preliminary screening process.
1. Subtask 1-a: Screening Signalized Intersections
a. Step 1 - Prepare a townwide traffic floxj map depicting the highest
monthly projected ADT's on the street network for the winter months
(November through March) of 1977-1978. This should be presented on a
suitable base map (or maps) at a scale of between 1 inch = 1,000 feet
and 1 inch = 3,000 feet; insets at a larger scale should be used, as
appropriate, for congested areas. Volumes should be included for all
principal streets including, as a minimum, all streets and highways on
the Federal Aid System and on all street sections controlled by traffic
signals.
b. Step 2 - Determine the locations where traffic signals are utilized
to control traffic.
c. Step 3 - Determine the configuration (i.e., the number of approach
and departure lanes) of each leg for all signalized intersections. Also,
a determination should be made as to whether each intersection is located
in a congested or noncongested area, and whether any of the locations
*
should be classified as complex intersections or special cases.
*
See Definitions in Section IV.H.
51
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d. Step 4 - Enter appropriate data for each signalized intersection on
the Preliminary Screening Work Sheet - Signalized Intersections (see
Section II.B.3), as follows:
1. Part I:
a. Enter the location (e.g., Main Street at Naussam Road).
2. Part II:
a. Record whether or not the location is generally within a
congested area (see Section IV.H).
3. Part III:
a. Record whether or not the location should be considered
a complex intersection or special case. If it is either
a complex intersection or a special case, enter the
location on the Initial Screening Summary Sheet (see
Section II.B.3) and proceed to the next intersection.
b. If the location is neither complex nor a special case,
proceed to Part IV.
4. Part IV: Each leg of the intersection is analyzed as follows:
a. Enter the leg designation (e.g., Main Street, south leg)
in column a. It is important to identify the particular
leg being considered (e.g., Main Street, south leg).
b. Enter the adjusted ADT (winter 1977-78) in column b.
c. Enter the configuration (e.g., 2-lane, 1-way) of the
leg in column c.
d. Enter the name and orientation (e.g., Main Street, east
leg) of each cross street leg on the line above columns
d through k.
e. For the first leg of the cross street:
1. Enter the adjusted ADT (winter 1977-78) in column d.
2. Enter its configuration (e.g., 2-lane, 1-way) in
column e.
52
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3. Enter the figure number and curve to be used for
screening in column f (see Section II.B.2 for
instructions on the selection of figures and curves).
4. Using the figure and curve noted in column f, deter-
mine whether or not hot spot potential exists; record
this determination in column g.
f. For the other leg of the cross street:
1. Enter the adjusted ADT (winter 1977-78) in column h.
2. Enter its configuration (e.g., 2-lane, 2-way) in
column i.
3. Enter the figure number and curve to be used for
screening in column j (see Section II.B.2 for
instructions on the selection of figures and curves).
4. Using the figure and curve noted in column j, deter-
mine whether or not hot spot potential exists; record
this determination in column k.
g. Repeat the previous steps in Part IV for each approach.
5. After all approaches have been analyzed, enter the location on
the Initial Screening Summary Sheet (see Section II.B.3); in-
clude the following data:
a. Location (street names).
b. Type (in this case, signalized intersection).
c. Whether or not a hot spot is indicated - this is affirma-
tive if any entry in columns g or k is affirmative.
e. Step 5 - Repeat Step 4 for all signalized intersections on the
street network.
2. Subtask 1-b: Screening Locations Where Conditions of Uninterrupted
Flow Prevail
a. Step 1 - Identify sections of expressway where the following con-
ditions prevail:
53
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Highway configuration APT
4-lane highway _> 30,000
6-lane highway >_ 40,000
8-lane highway _> 50,000
b. Step 2 - For each section identified in Step 1 as meeting the above
criteria, enter the highway name or route number in column a of the Pre-
liminary Screening Work Sheet - Uninterrupted Flow (see Section II.B.3).
Also on this work sheet, enter the following data for each location:
1. Description of the location (e.g., north of the Brook's High-
way Interchange) in column b.
2. The adjusted ADT (winter 1977-78) in column c.
3. Highway configuration (e.g., 4-lane expressway) in column d.
4. Estimated lane capacity in column e.
5. Using the appropriate curve in Figure 10, determine whether
or not the facility is a potential hot spot (for instructions
on selecting the appropriate curve and use of the figure, see
Section II.B.2); record this determination in column f.
c. Step 3 - Upon completion of Step 2, record the locations on the
Initial Screening Summary Sheet; include:
1. Facility name and location (from columns a and b of the
work sheet) .
2. Type of facility (in this case, expressway-uninterrupted
flow).
3. Whether or not hot spot potential is indicated (from
column f of the work sheet).
d. Step 4 - Identify arterial street sections on the highway network
that meet the following criteria:
54
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1. Volumes:
Highway configuration APT
2-lane arterial >_ 1
4-lane arterial _> 16,000
6-lane arterial _> 20,000
2. Proximity to Signalized Intersections: The section should be
at least 1 mile from a signalized intersection.
e. Step 5 - For each arterial section identified in Step 4 as meeting
the above criteria, enter the street name (or other identifier) in
column a of the Preliminary Screening Work Sheet - Uninterrupted Flow
(see Section II.B.3). Also on this work sheet, enter the following
data for each location:
1. Description of the location (e.g., between Marginal Way
and Ober Road) in column b.
2. The adjusted ADT (winter 1977-78) in column c.
3. Street configuration (e.g., 4-lane arterial) in column d.
4. Estimated lane capacity in column e.
5. Using the appropriate curve in Figure 11, determine whether
or not the facility is a potential hot spot (for instructions
on selecting the appropriate curve and use of the figure, see
Section II.B.2); record this determination in column f.
f. Step 6 - Upon completion of Step 5, record the locations on the
Initial Screening Summary Sheet; include:
1. Facility name and location (from columns a and b of the
work sheet).
2. Type of facility (in this case, arterial-uninterrupted flow).
3. Whether or not hot spot potential is indicated (from
column f of the work sheet).
55
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3. Subtask 1-c: Screening of Nonsignalized Intersections
a. Step 1 - Identify all nonsignalized intersections where either the
major street or minor street volumes exceed the critical volumes shown
below (for various street configurations) :
Street configurations
Major street
2-lanes
4-lanes
4-lanes
Minor street3
2-lanes
2-lanes
4-lanes
Critical volumes
Major street
10,000
20,000
20,000
Minor street3
2,500
2,500
8,000
Under control of STOP sign.
b. Step 2 - For each intersection identified in Step 1 as meeting the
above volume criteria, enter the location in Part I of the Preliminary
Screening Work Sheet - Nonsignalized Intersections (see Section II.B.3).
c.
Step 3 - For Part II of the work sheet enter the following:
1. For the major through street enter:
a. Adjusted ADT (winter 1977-78) in column a.
b. Configuration (e.g., 2-lane arterial) in column b.
c. Estimated lane capacity in column c.
d. Using the appropriate curve in Figure 11, determine
whether or not hot spot potential exists on the through street
(see Section II.B.2 for instructions on selecting the
appropriate curve); record this determination in column d.
2. For the first cross-street leg enter:
a. Street name and its orientation (e.g., Trask Lane,
east leg).
56
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b. Adjusted ADT (winter 1977-78) in column e.
c. Configuration (e.g., 2-lane, 2-way) in column f.
d. The figure number and curve to be used for screening
in column g (see Section II.B.2 for instructions on
the selection of figures and curves).
e. Using the figure and curve designated in column g,
determine whether or not hot spot potential exists;
record this determination in column h.
3. For the second cross-street leg enter:
a. Street name and its orientation (e.g., Trask Lane,
west leg).
b. Adjusted ADT (winter 1977-78) in column i.
c. Configuration (e.g., 2-lane, 1-way) in column j.
d. The figure number and curve to be used for screening
in column k (see Section II.B.2 for instructions on
the selection of figures and curves).
e. Using the figure and curve designated in column k,
determine whether or not hot spot potential exists;
record this determination in column 1.
d. Step 4 - Upor. completion of Step 3, record the locations on the
Initial Screening Summary Sheet; include:
1. Location (street names).
2. Type (in this case, nonsignalized intersection).
3. Whether or not a hot spot is indicated - this is affirmative
if any entry in columns d, h, or 1 is affirmative.
4. Other Locations
Other locations may be identified during the initial screening that
should be analyzed for possible hot spot potential. These locations
may not be obvious solely from analysis of traffic data; however,
57
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interviews with local planning or engineering personnel may result in
the identification of such locations. These special cases may include
access roads to major industrial facilities or office complexes, shop-
ping centers, or public parking areas. Should locations such as this
be identified, they should be entered on the Preliminary Screening
Summary Sheet.
5. Preliminary Screening Locations Map
The final step in the preliminary screening process is to assign an
identification number to each location listed on the Initial Screening
Summary Sheet, and then to plot the locations, with their respective
identification numbers, on a base map. In preparing this map, separate
symbols should be utilized to distinguish signalized intersections,
nonsignalized intersections, and locations where uninterrupted flow
prevails. Examples of this type of map are illustrated as Figures' A-la
and A-lb in Appendix A.
58
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D. REFERENCES
1. Guidelines for Air Quality Maintenance Planning and Analysis.
Volume 9: Evaluating Indirect Sources. U.S. Environmental Pro-
tection Agency, Research Triangle Park, North Carolina 27711.
Publication Number EPA-450/4-75-001. January 1975.
2. Highway Capacity Manual. Highway Research Board, National Academy
of Sciences. National Research Council. Washington, D.C. Special
Report No. 87. 1965.
59
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SECTION III
TASK 2 - HOT SPOT VERIFICATION
A. INTRODUCTION
Section II presented a technique for identifying locations on a highway
network where a potential exists for traffic-generated carbon monoxide
levels to exceed the National Ambient Air Quality Standard (NAAQS) for
8-hour average concentrations. This so-called preliminary screening
technique was designed specifically for performing an areawide assessment
of an entire city or town using only the most basic data elements and a
number of simplifying assumptions. It was stressed that various as-
sumptions used in developing the initial screening technique were in-
tentionally conservative. As a result, many of the locations identified
as potential hot spots by the initial screening process may, in fact, not
be hot spots after all. In order to verify the hot spot potential of a
location further analysis is required utilizing a technique that accounts
for physical and operational characteristics particular to that location.
The purpose of this section, then, is to present a technique for verifying
the hot spot potential at locations where the preliminary screening process
indicated that such potential exists.
60
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B. OVERVIEW OF HOT SPOT VERIFICATION
The verification process is a follow-up to the initial screening of an
area. The intent is to perform a more precise evaluation of the hot spot
potential of a street section or intersection utilizing a technique that
permits input of parameters specific to that location rather than assumed
parameters. Whereas the initial screening process focused on identifica-
tion of potential hot spot locations anywhere within a city or town
(therefore requiring a very general approach) the verification process
involves analysis of specific locations; therefore a more detailed analy-
sis of each location is feasible.
The technique involved is, conceptually, identical to that used for pre-
liminary screening — that is, it is assumed that an explicit relation-
ship exists between air quality and parameters such as traffic operating
characteristics, and physical characteristics of an intersection, for
particular meteorological conditions. Therefore, if both traffic and
physical characteristics are determined and a particular set of meteo-
rological conditions assumed, estimates of the resulting air quality can
be made. Again, these estimates are made utilizing a series of nomo-
graphs which express a quantitative relationship between various traffic
and roadway characteristics, and resulting air quality.
In discussing the verification process it is necessary to first consider
the three basic elements incorporated into the procedure — these in-
clude the data necessary, the nomographs to be used, and a set of stan-
dard forms to be used for performing and recording the verification of
potential hot spots.
1. Data Required
Whereas in the preliminary screening process it was emphasized that maxi-
mum use should be made of existing general traffic data, the verification
process requires current data specific to each site analyzed. This is
61
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not to say, however, that use cannot be made of existing data; on the
contrary — use of existing data is encouraged if it is determined by
responsible traffic engineering or planning personnel to be representative
of current traffic conditions and if it is sufficient in detail. The par-
ticular data elements are described below.
a. Location Sketch - A sketch should be prepared of each location re-
quiring verification. This sketch should show:
• the approximate geometry of the location
• the number of approach and departure lanes on each leg
if the site is an intersection, or just the number of
lanes if the site is an expressway or midblock location;
a number should be assigned to each lane and recorded
on the sketch
« the width of each lane, median, and channelizing island
e the locations within each site where curb parking is
permitted and where bus stops and taxi stands are
located
« the locations on both sides of each street or roadway
where a reasonable receptor is identified
• pertinent notes regarding observations as to the operation
of the facility.
Examples of field sketches that include the data required are provided
throughout Appe'ndix C.
b. Traffic Volume Data - Peak hour volume data is required for all
streets and highways analyzed. Again, these volumes should be repre-
sentative of the busiest winter month (November through March) projected
to 1977-78. This implies that a statistical data base must also be
available from which projections are made. The lane distribution of peak
hour traffic is also required since computations of carbon monoxide con-
centrations are performed on a larie by lane basis.
62
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While traffic volume data are often the most abundent data element gen-
erally available, it is doubtful that in many instances sufficient data
will exist to perform hot spot verification, implying that new data will
be required. Again, the appropriateness of existing data should be
judged by a competent traffic engineer or planner. In fact, the develop-
ment of all traffic volume data used in the verification process should
be accomplished by a competent engineering/planning professional, this
may require direction at the state level. This applies to most of the
data development effort required.
c. Vehicle Classification Data - A related element required is the dis-
tribution of traffic by vehicle type. This is usually developed for
specific highway classifications such as expressways, major arterials,
minor arterials, etc. The vehicle classifications that should be
identified include:
• light-duty vehicles (passenger cars)
• light-duty trucks (panel and pick-up trucks, light
delivery trucks — usually all 2-axle, 4-wheel trucks)
• heavy duty, gasoline-powered vehicles
• diesel-powered vehicles
These data may be available for a community where recent comprehensive
transportation planning programs have been accomplished.
d. Traffic Signal Data - A necessary element in the verification of hot
spot potential at signalized intersections is the ratio of the green time
allocated to each approach, to the total cycle length (G/Cy). This ratio
can be determined from records or design plans if the installation is of
the fixed-time type but if actuated control is utilized, the ratio must
be computed based on the actual peak hour volumes.
63
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Where actuated pedestrian signals are utilized estimates should be made
with regard to the number of times during the peak hour that the actuated
pedestrian phase is called. Also, where turning lanes are provided but
these lanes are subject to interference from stopped through traffic,
estimates of this interference should be made. The green time allocated
to the approaches affected by these occurrences then must be adjusted.
Further explanations of computing G/Cy, including adjusting for inter-
ference, are provided in Section IV.A.
e. Lane Capacity - Lane capacity for expressways and midblock locations
must be computed from the appropriate data described above. Calculating
lane capacity is usually a relatively straightforward procedure; however,
in certain instances the computations involve engineering judgments that
should be performed by experienced traffic engineering professionals. A
valuable source for information regarding the computation of roadway or
lane capacity is the 1965 Highway Capacity Manual. Further discussion
of capacity is provided in this document in Section IV.E.
f. Vehicle Cruise Speed - Estimates of the cruise speed of vehicles
departing from signalized intersections must be made. These can be based
on actual field trials or through estimates based on observed operating
characteristics and surrounding land use. Further discussion of the pro-
cedures involved appear in Section IV.D.
g. Miscellaneous Data - Other data may be required to perform hot spot
verification. Included is information relative to planned projects which
will directly impact traffic or travel within the study area in the near
future. These could involve alterations to the street network, including
the addition or deletion of major arterials or expressways, revising cir-
culation patterns, changing signal systems, etc.; or the development of
programs which focus on creating mode shifts (e.g., improving bus service
for commuters). The expected effect on traffic volumes must be considered
where.these possibilities exist.
64
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Another area of consideration is with regard to the effects of programs
which will have an impact on automotive emissions, such as mandatory in-
spection and maintenance programs. Where such programs are in effect or
are anticipated, their impacts must be estimated. Section IV.B discusses
the method for incorporating these impacts into the verification process.
2. Hot Spot Verification Nomographs
Presented here is a series of nomographs to be used for verification of
hot spot potential at three general types of locations, including sig-
nalized intersections, uninterrupted flow, and nonsignalized inter-
sections. It should be noted that these curves represent concentrations
expected from a vehicle mix during the winter of 1977-78.
a. Signalized Intersections - For hot spot verification a lane-by-lane
analysis is performed for each leg to estimate the total carbon monoxide
contribution from that lane. These lane concentrations are then adjusted
for distance from an identified receptor, the sum of which is the esti-
mated receptor concentration.
For signalized intersections, approach lane and departure lane concentra-
tions are computed on separate nomographs. The nomograph used for ap-
proach lanes, Figure 23, shows traffic demand per lane in vehicles per
hour (abscissa) versus carbon monoxide concentrations in ppm (ordinate).
Also, seven curves have been plotted that correspond to various G/Cy (see
Section IV.A) for the lane. In using the nomograph, the estimated peak
hour lane volume and the G/Cy for the lane are established and from these,
a resulting concentration is determined.
For each departure lane, the nomograph presented in Figure 24 is utilized.
In this figure it is seen that lane concentrations for any particular
hourly volume are a function of the departure cruise speed. Therefore,
to use this nomograph to estimate lane concentrations, both peak hour lane
volume data and an estimate of the average departure lane cruise speed are
required.
65
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Implicitly the nomograph specifies that the concentrations determined are
representative of those concentrations estimated to occur 10 meters away
from the edge of the traffic lane. In order to determine the concentra-
tion at a receptor located at a distance of other than 10 meters, each
lane concentration must be adjusted by some factor which accounts for the
actual distance between the edge of the lane and the receptor site. These
factors can be determined from Figure 25, which depicts relative concen-
trations as a function of distance from the emissions source (in this
case considered to be the near edge of the traffic lane) for both approach
and departure lane traffic.
1. Nomographs for Verification at Signalized Intersections - The
nomographs to be used for verifying hot spot potential at signalized
intersections are presented in Figures 23, 24 and 25, below.
b. Uninterrupted Flow - Two nomographs are presented for estimating lane1
concentrations where conditions of uninterrupted flow occur. The first
of these, Figure 26, expresses lane concentration as a function of the
volume to capacity ratio (V/C) and the lane capacity for freeways or
expressways. Again, the concentrations are assumed to occur a distance
of 10 meters from the edge of the lane.
A corresponding nomograph for arterial streets is presented in Figure 27.
Again, lane concentrations are shown to be a function of V/C and lane
capacity.
Correction factors for varying lane edge to receptor distances are shown
in Figure 28.
1. Nomographs for Verification of Locations Where Uninterrupted Flow
Prevails - The nomographs to be used for verification of hot spot potential
on expressways and midblock locations of arterial streets are shown in
Figures 26, 27 and 28, below.
66
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200
400
600 800 100Q 1200
TRAFFIC DEMAND PER LANE.vph
1400
1600
Figure 23.
Maximum impact of traffic in an approach lane upstream from
a signalized intersection at a receptor site located at a
perpendicular distance of 10 meters, 1977
67
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200 400 600 800 1000 1200 1400
TRAFFIC DEMAND PER LANE.vph
1600
Figure 24.
Maximum impact of traffic in a Lane downstream from an
intersection at a receptor site located a perpendicular
distance of 10 meters away, 1977
68
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1.3
1—I—I I I I
10 20 30 40
£0 CO
70
£0 90 100 110 120 130 140 150 150 170 ISO ISO 200
PERPENDICULAR DISTANCE FROM THE NEAR EDGE OF A TRAFFIC LANE. miUn
Figure 25. Relative concentration of CO versus perpendicular distance from a traffic lane near
a signalized intersection
-------
0.8
0.1
0.3 0.4 0.5 0.6 0.7
VOLUME DEMAND TO CAPACITY RATIO (v/c)
0.8
0.9
1.0
Figure 26. Volume demand - capacity ratio in a freeway or expressway
lane versus CO concentration impact at a perpendicular
distance of 10 meters, 1977
70
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0.8
0.1
0.2
0.3 0.4 0.5 0.6 0.7
VOLUME DEMAND TO CAPACITY RATIO (v/c)
0.8
Figure 27. Volume demand - capacity ratio in a lane on a major street
versus CO concentration impact at a perpendicular distance
of 10 meters, 1977
71
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I I I I I I I
PERPENDICULAR DISTANCE FROM THE NEAR EDGE OF A TRAFFIC LANE.mtttu
Figure 28. Relative concentration of CO versus perpendicular distance
from a traffic lane with freely flowing traffic
-------
c. Nonsignalized Intersections - Carbon monoxide concentrations at STOP-
sign controlled intersection legs are estimated from the nomograph
presented in Figure 29, for the approach lanes, and Figure 24 for departure
lanes. It is seen from Figure 29 that concentrations are a function of the
V/C and lane capacity. However, it is also shown that once the V/C
reaches a certain point queuing occurs on the approach and concentrations
increase sharply. For example, if the V/C is 0.6 and the lane capacity
is about 500 vehicles per hour, the resulting lane concentration is about
3.4 ppm. If conditions were such that queuing did not occur, the same
V/C and capacity would result in a lane concentration of about 2.5 ppm.
Lane edge to receptor distance correction factors are shown in Figure 30.
These factors are applied directly to the lane concentrations computed
from Figures 24 and 29.
1. Nomographs for Verification at Nonsignalized Intersections - The
nomographs for determining approach lane concentrations and correction
factors are presented in Figures 29 and 30, below, while the nomograph for
estimating departure lane concentrations is presented in Figure 24.
3. Hot Spot Verification Forms
Presented below are standard forms to be used as work sheets and summary
sheets for verifying hot spot potential. These forms should also be used
for reporting hot spot verification. Included are the following:
• Hot Spot Verification Summary Form 5
• Hot Spot Verification Work Sheet -
Field Data Form 6
* Hot Spot Verification Work Sheet -
Signalized Intersections Forms 7a, 7b, 7c
• Hot Spot Verification Work Sheet -
Uninterrupted Flow Form 8
• Hot Spot Verification Work Sheet -
Nonsignalized Intersections Forms 9a, 9b
73
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02 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0
VOLUME DEMAND TO CAPACITY RATIO (v/c)
Figure 29. Impact of traffic upstream from a nonsignalized intersection
on CO concentrations at a receptor site located a perpendic-
ular distance of 10 meters away, 1977
-------
u
I I I III I I I I I
10
20 30
40
SO 60 70 80 90 100 110 120' 130 140 150 ISO
PERPENDICULAR DISTANCE FROM THE NEAR EDGE OF A TRAFFIC LANE, meters
170 ISO ISO 200
Figure 30. Relative concentration of CO versus perpendicular distance from a traffic lane near
a nonsignalized intersection
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A brief description of each of these forms is presented below.
a. Hot Spot Verification Summary (Form 5) - This form is intended to be
used for summarizing the hot spot verification effort. To complete the
form the location number (corresponding to the number assigned to the
location during preliminary screening), location name, and the maximum
concentration computed, are entered. It is noted that for all inter-
sections and many expressways and midblock arterials analyzed, more than
one concentration will be computed. It is emphasized that only the
maximum of all those concentrations computed for any one location should
be entered on the Summary Sheet.
b. Hot Spot Verification Work Sheet — Field Data (Form 6) — This form
provides space for a sketch of the facility or site being evaluated.
Included in the sketch should be those elements mentioned in the previous
text (Section III.B.I.a) regarding the geometry, layout, and physical
dimensions of the site. Also, notes regarding traffic operations, recep-
tor type, terrain features, land-use characteristics, etc., should be
included. The orientation of the site should be indicated using a north
arrow. If various abbreviations are used in preparing the site sketches,
these should be consistent throughout; also, these should be defined in at
least one location. Examples of completed Field Data Forms are provided
throughout Appendix C.
c. Hot Spot Verification Work Sheet — Signalized Intersection (Forms 7a,
7b, 7c) — This is a three-page form used to verify the hot spot potential of
one signalized intersection. As can be seen, this form is composed of
several parts; each of these is described briefly below.
Part I provides space for recording the peak hour volumes for each lane
on each intersection leg. In the first column under the heading "Inter-
section Leg," the street name and its orientation should be entered. The
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HOT SPOT VERIFICATION SUMMARY
City/Town: State: page of
Analysis By: Date:
(IUM) (CUlt)
Approved By: Date:
(DAM) (title)
, .. „ Maximum 8-hr.
Location No. Location Ave> Concentration
Form 5
77
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HOT SPOT VERIFICATION WORK SHEET - FIELD DATA
City/Town: By:_
Location: Date
Sketch of location and notes:
Form 6
78
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HOT SPOT VERIFICATION WORK SHEET - SIGNALIZED INTERSECTION
page 1 of
City/Town/:
By:
Intersection:
Date:
I. PEAK HOUR WLUHES: Enter Una Numbers (from sketch) and paak hour volume* for winter 1977-78
(from data aheoca).
•
Interaction L»g
Peak Hour Volume*
Appro a tit Lsn* No.
Departure Lan« Ho.
II. AVERAGE C/Cy AND CRUISE SPEED: Enter average C/Cy for approach lanes (from data sheets) and
average cruise speed for departure lanes.
InteriecttoD Leg
Average C/Cy
Approach Lane No.
Averoge Cruiaa Speed
Departure Lane No.
III. RESULTING LANE CONCEITRATIONS: Enter lane concentrations for Approach lanes (obtained from
Figure No. 23), and departure lane concentrations (obtained from Figure No. 24).
Interaction L»g
Computed Lane Concentrct loni
Approach Lane Ho.
Departure Line No .
Form 7a
79
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HOT SPOT VERIFICATION WORK SHEET - SIGNALIZED INTERSECTIONS (continued)
page 2 of
Intersection: City/Town/:
IV-A. LANE EDGE TO RECEPTOR DISTANCE CORRECTION FACTORS: Enter lane edge to receptor distance correction
factor for each lane (obtained froa Figure No. 25) assuming receptor is on the approach side of
each leg.
Interjection L«l
Diitance Correction Factor*
Approach Lane Ho.
Departure Lane No.
IV-B. LAXE EDGE TO RECEPTOR DISTANCE CORRECTION FACTORS: Enter lane edge to receptor distance correction
factor for each lane (obtained from Figure No. 25) assuming receptor i« on the departure side of
each leg.
IntertectloQ Leg
'
Approach
Lane No.
Dcpartur
! Luna No.
V-A. RECEPTOR CONCENTRATIONS ATTRIBUTABLE TO EACH LANE: Enter the concentration from each lane corrected
for lane edge to receptor distance; this is computed as Che product of lane concentrations (from III.
above) and the corresponding lane edge to receptor distance correction factor (from IV A, above);
assuming receptor is on the approach side of each leg.
Intersection Leg
Corrected L*ne Concentration!
Approach Lan« No.
Departure Lant No.
Form 7b
80
Total
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HOT SPOT VERIFICATION WORK SHEET - SIGNALIZED INTERSECTIONS (Continued)
page 3 of_
Intersection; City/Town/:
V-B. RECEPTOR CONCENTRATIONS ATTRIBUTABLE TO EACH LANE: Enter the concentration from each lane corrected
for lane edge to receptor distance; this li computed as the product of lane concentration (fros III,
above) and the corresponding inne edge to receptor distance correction factor (froo IV-B, above);
aaauolng receptor la on the departure aide of each leg.
.
Approach
Un« Ho.
Dcptrtur
r L«ne No,
Tot* I
YI-A. FINAL COMPUTATIONS FOR MAXIMUM 1-HR AND 8-HR AVERAGE CONCENTRATIONS: Enter the following data:
(1) receptor concentration (from V-A, above) In column a; (2) ivm (from data eheet) In column b;
(3) background concentration (5ppm unices determined otherwise) In column d; and (4) 8-hr
correlation factor (0.7 unices determined otherwise) In column f. Compute concentrations as
ihovn In column c, e, and g. Assume receptor la on the approach side of each leg.
Zntcriectloa Leg
•
Computed
Receptor
Cone.
b
'v.
c
Cone.
(» X t>)
d
ground
Cone,
•
Tot.l
Cone.
-------
HOT SPOT VERIFICATION WORK SHEET - UNINTERRUPTED FLOW
City/Town:
page.
By: _
of
Street/Highway Section:
Date:
I. BASIC COMPUTATIONS:
I ten
A. TOL'k.~£S: Cnter peo'it hour volumes for winter
1977-73 (frrn data sheets)
sheets)
C. V/C: Enter V/C for each lone (A -r B, above)
computed iroo A and C, above, and Figure 26 or 27
>ound Lane
ound Lane I
*o.
II. CORRECT FOR LANE EDGE TO RECEPTOR DISTANCES:
Assume receptor is on
side of street
Item
A. LAST. EDCE TO RECEPTOR DISTANCE CORR-
ECTION FACTORS: Enter lane edge to
ft. RECEPTOR CONCErTRATIOSG ATTRIBUTABLE
trationa , computed a* ths produce of
I-D and II-A, above
bound L>nc
No.
sound L*n«
No.
V
/ \
7 \
Assume receptor is on
side of street
ItM
C. LAKE EDGE TO RECEPTOR DISTANCE CORR-
ECTION FACTORS: Eater lane edge to
receptor distance correction factors
for each lane (obtained from Fig. 28)
a RECEPTOR CONCErTB.'vTlONS ATTRIBUTABLE
TO EACH LANE: Enter corrected concen-
trations, computed ai the product of
I-D and II-C, above
bound Lana Ha,
TOTAL
X
III. FIKAL COMPUTATIONS OF MAXIMUM 1-HR AND 8-HR AVERAGE CONCENTRATIONS
A. FI;:\L a»>:K7AT:o:;s OF I-HR ANTJ S-HR AVERAGE
CTNCCyrRMICXS: Enter the following; (1)
total rec*ptor concentration) (fro* II-5
and II-D. above) In colunn a; (?) f ( f roa
da:a I'-eets) In colurn b; (3) bac>Kround
wise) In column d; (6) 9-hr correlation fac-
tor (0.7 ur.leis ot.ucrvlac Cctcrcinci) In
coluca f. Corjpute final concentration* ai
f hova to col uor.i c, «, and j, for receptor I
Receptor
(utreet-
• ide)
•
Receptor
Cone.
b
fvn
e
Cone.
(• x b)
d
ground
Cone.
«
1-hr ave.
Cone.
(c + d)
t
Correlac.
Foctor
(
Ave. Cone.
<« X {)
Form 3
82
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HOT SPOT VERIFICATION WORK SHEET - NONSIGNALIZED INTERSECTIONS
page 1_ of
City/Town:
By:
Intersection:
Date:
Type of Control: all-way STOP;
Street Controlled:
.1 or 2-way STOP; .YIELD; None;
I. BASIC COMPUTATIONS:
Item
A. WLtttES: Enti-r peak hour vnluiaci for vlntor
1977-78 (frc-a data sheets)
B. IAXE CAPACITY: Enter lane capacity of approach
lanes (fron data Ehcets)
C. V/C: Crttcr V/C for Approach i.uec (computed aa
as A 7 B, abcve)
speed (frora dzta shecta)
E. IAXZ CONCENTRATIONS: Enter lv\« concentraciona
coapuod froa A, C, and D, above, and Fig. 29 i 2i
Leg:
Approach Lane Mo.
^x^
^x^
Departure Lftne Ko«
X
X
^x^
^x^
Leg-'
Approach Lane No.
x
x^
Doparture Lant No.
^x
^><^
^
II. CORRECT FOR LANE EDGE TO RECEPTOR DISTANCES:
Assume receptor is on
side of street
Itea
A. IAHE EDGE TO RECEPTOR DISTANCE CORR-
ECTION FACTORS: Enter Un* edge to
for each -lane (obtained froa Fig. 30)
1. RECEPTOR CONCENTRATIOKS ATTRIBUTABLE
tritlooJ, computed •• th« product of
I-Z *ai II-A, »bov.
Le8: . „-.
Approach Lane Mo.
Departure Lane No.
TOTAL
X
Le
-------
HOT SPOT VERIFICATION WORK SHEET - NONSIGNALIZED INTERSECTION (continued)
page 2 of
City/Town:
Intersection:
Street Controlled:
III. FINAL COMPUTATIONS OF MAXIMUM 1-HR AND 8-HR AVERAGE CONCENTRATION
Intersection Leg:
I tea
A.. riKM COGITATION'S OP 1-HR AXD S-HR AVERAGE
CO^Ct^TRAriONS: Enter the following; (I)
and 1I-D, above) In column a; (2) f^ (from
concentration (5ppm unless dete rained other*
ohown ia colu^~» c, c, and g, for receptori
on both at&ca of atreet
Receptor
Location
(•erect-
aide)
«
Computed
Receptor
Cone.
b
*v.
C
Corrected
Cone.
(« x b)
d
Back-
ground
Cone.
•
Total
1-hr ave.
Cone.
(c + d)
f
8-hr.
Correlac.
Jactoc
(
Eat. 8-hr
Ave. Cone.
(« x f>
Intersection Leg:
I tea
A. rr^L COGITATION'S OF 1-HR AXD 8-HR AVERAGE
CON'C^TRATION'S: Enter the following; (1)
total receptor concentrations (fro-n II-D
• nrf II-D, above) In column 4; (2) f^ (from
data iheets) In column b; (3) background
wlie) in coluon d; (4) 8-hr correlatton fac-
tor (0.7 unless otherwise dcternln^d) In
colunn f. Coz^ute final concentrations .ti
ahown in column c, e, and g, for receptor*
on both ildej of itreet
Receptor
aide}
•
Cone*
b
'VB
e
(• x b)
4
Cone.
•
1-hr ava.
Cone.
(c + d)
t
Correlac.
Factor
8
Hit 8-hr
Ave. Cone.
(• x O
Fora 9b
84
-------
assigned lane numbers (see Section III.B.I.a., the second item in the list-
ing) should be recorded under the subheadings "Approach Lane No." and
"Departure Lane No."; the entries mentioned to this point should be
repeated in Parts II through V-B. To complete Part I, the peak hour volumes
representing 1977-78 traffic should be entered for each lane.
In Part II, the G/Cy and the estimated departure cruise speed for each
approach and departure lane, respectively, are entered. Instructions for
estimating G/Cy and cruise speed are provided in Sections IV.A and IV.D,
respectively.
From the data contained in Parts I and II, lane concentrations are computed
using Figures 23 and 24. These are entered in Part III.
Part IV is divided into IV-A and IV-B. In both Parts IV-A and IV-B, the
lane edge to receptor distance correction factor, obtained from data
provided in the site sketch and Figure 25, is entered. In IV-A, the fac-
tor is based on a receptor located on the approach side of the street,
while the factor to be entered in IV-B assumes that the receptor is
located on the departure side of the street.
The lane concentrations entered in Part III are multiplied by the lane
edge to receptor distance correction factors entered in Part IV-A, and the
product entered in Part V-A. The lane concentrations in Part III are then
multiplied by the lane edge to receptor correction factors appearing in
Part IV-B, and the results entered in Part V-B. The corrected lane con-
centrations are then summed for each intersection leg.
In Parts VI-A and VI-B the final total concentrations are computed for
receptors on the approach and departure sides of each leg, respectively.
In these computations a local emissions correction factor, f (see
vm
Section IV-B), is applied to the concentrations in Parts V-A and V-B,
and a background concentration is added to this, yielding a total 1-hour
85
-------
average concentration. An 8-hour correlation factor (see Section IV.F)
is then applied to yield an estimated maximum 8-hour average concentra-
tion. Sample completed forms appear in Appendix C.
d. Hot Spot Verification Work Sheet — Uninterrupted Flow (Form 8) — This
is a three-part form used to verify hot spot potential on expressways,
midblock sections of arterial streets, or other locations where conditions
of uninterrupted flow prevails. In Part I, the peak hour volumes and
capacity for each lane of the roadway are entered on lines A and B, and
the ratio of the volume to the capacity for each lane is entered on line C.
Using the V/C and volume for each lane, individual-lane concentrations are
computed using the nomograph provided in either Figure 26 for expressways,
or Figure 27 for arterial streets.
In Part II, lines A and B, the lane edge to receptor distance correction
factor and the corrected lane concentrations are entered. It should be
indicated which side of the facility the receptor is located on. The
lane edge to receptor distance correction factor is obtained from Figure 28.
The same types of data are entered on lines C and D but assuming the re-
ceptor is located on the opposite side of the roadway.
In Part III, the final computations are performed by adjusting the concen-
trations determined in Part II-B and II-D, for local emissions and back-
ground concentrations, and then to obtain the 8-hour average. The top line
is used for the concentration computed in Part II-B, while the bottom line
is for the concentration in Part II-D. Sample completed forms appear in
Appendix C.
e. Hot Spot Verification Work Sheet — Nonsignalized Intersections (Forms 9a.
and 9b) — This is a two-page form used for verifying hot spot potential
on the controlled leg(s) of a nonsignalized intersection. Two legs can
be evaluated on each form.
86
-------
In Part I, the peak hour volume and capacity of each lane of the controlled
intersection leg are entered on lines A and B, respectively. The ratio of
the volume to capacity, V/C, for each lane is then entered on line C and
resulting lane concentrations are computed from the lane volume and V/C,
using the nomograph provided in Figure 29.
In Part II-A and II-B, the lane edge to receptor distance correction factor
(obtained from the nomograph presented in Figure 30) and corrected lane
concentrations are entered. The same data is entered in II-C and II-D for a
receptor located on the opposite side of the street. In each case, it
should be indicated which side of the street the receptor is assumed to be
located on.
In Part III-A, final computations are made, adjusting the concentrations
computed in Part II for local emissions and background, and further adjust-
ing the concentration to represent the 8-hour average. The two lines are
provided in order to compute concentrations at receptors located on both
sides of the intersection leg. Part III-B is provided for computing con-
centrations on the second leg (if any) of the intersection. The inter-
section leg being analyzed should be entered on the line provided. Sample
completed forms are provided in Appendix C.
4. Performing Hot Spot Verification
Before discussing the detailed instructions for hot spot verification, it
may be helpful to see generally how the various data, nomographs, and forms
are utilized. This is best illustrated by the flow diagram provided in
Figure 31.
The flow diagram illustrates that as a result of the preliminary screening
process, locations analyzed can be classified as not having hot spot poten-
tial, having hot spot potential, or as being either a complex intersection
or special case (in either instance, nothing is implied regarding hot spot
87
-------
CAPACITY
DATA
COMPILE SPECIFIC TRAFFIC, ROADWAY, LAND
USE AND MISCELLANEOUS DATA FOR EACH
LOCATION
PEKFOHU HOT SPOT V L >< If 1C A T ION
Of SIGNALLED INTERACT
PERFORM HOT SPOT VESIFICATIC-:
FOR UNINTERRUPTED FLOW
PERFORM HOT SPOT VERIFICATION
FOR NONSIGMALIZCD INTERSECTIONS
MISC.
DATA
USE FIGURES 26,27728)
USE FORMS S'.j)
USE FORMS 6,9a,9b
ENTER CONTROL STPATCCY
PLANNING AND ANALYSIS
PHASE
Figure 31. Process flow diagram for the hot spot verification procedure
88
-------
potential). The diagram further illustrates that only locations classified
as having hot spot potential or as being complex or special cases, are
considered in the verification process.
The remainder of the diagram shows the order in which analyses are performed
and which nomographs and forms are used for each portion of the analysis.
It is also shown that for locations where hot spot potential is confirmed,
further analyses are required involving the development of control measures
and more sophisticated air quality analyses. This advanced phase of the
overall process for assessing carbon monoxide problems is beyond the
immediate scope of this document.
89
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C. DETAILED INSTRUCTIONS FOR PERFORMING HOT SPOT VERIFICATION
As mentioned previously, the hot spot verification process permits data
specific to a particular location to, be utilized to determine the like-
lihood of carbon monoxide hot spots occurring. ... This technique also pro-
vides a quantitative analysis.that can be utilized to .compare relative
hot spot potential throughout a highway network. For this reason the
verification procedure can be very useful not only for identifying
hot spots, but also as an aid in the planning process for resolving
hot spot problems.
The general procedure involves obtaining data specific to each location
and relating these data to air quality, again through the use of a
series of nomographs (see Section III.B.I). The data requirements for each
* ,
location type (e.g., signalized intersections, nonsignalized intersections,
free flowing street/highway sections) vary somewhat as will be indicated
by the instructions which follow.
1. Subtask 2-a; Hot Spot Verification at Signalized Intersections
a. Step 1 - Prepare a sketch of each intersection on a Hot Spot Verifi-
cation Work Sheet - Field Data (see Section III.B.3); include the following
data:
1. Approximate geometry of the intersection.
2. The number of approach and departure lanes on each leg;
also, assign a number to each lane on each leg.
3. The width of each lane, median, and channelizing island.
4. The locations within the intersection where curb parking is
permitted and where bus stops or taxi stands exist.
5. The location on each leg where a reasonable receptor (see
Section IV.C) is identified; these should be identified
on the sketch as receptors, and the distance from these
to the nearest edge of each street lane must be provided.
90
-------
6. Pertinent notes regarding observations as to operation of
the intersection, interference to traffic flow by pedes-
trians or other frictions, surrounding land use, estimated
departure speeds, etc.
7. All street names and a north arrow.
b. Step 2 - The following pertains to the Hot Spot Verification Work
Sheet - Signalized Intersections (see Section T.II.B.3). These should be
completed for each intersection as follows:
1. Enter the data indicated in the heading.
2. Part I:
a. For each leg enter the street name and its orientation
(e.g ., Newton Road, east leg) in the first column.
b. Enter the lane number (see item 2 in Step 1, above)
for each approach and departure lane, as indicated.
c. Enter the adjusted peak hour volume (winter 1977-78)
for each approach and departure lane.
3. Part II:
a. For each leg enter the street name and its orientation,
and the lane numbers.
b. Enter the average G/Cy (see Section IV.A.) for each
approach lane, and the estimated average cruise
speed (see Section IV.D.) for each departure lane.
4. Part III:
a. For each leg enter the street name and its orientation,
and the lane numbers.
b. Using the approach lane volumes and corresponding
G/Cy (from Parts I and II, respectively) and Figure 23,
compute the approach lane concentrations; record these
in Part III.
c. Using the departure lane volumes and corresponding de-
parture cruise speed (from Parts I and II, respectively)
and Figure 24, compute the departure lane concentrations;
record these in Part III.
5. Part IV-A (Assume that the receptor is on the approach
side of each leg):
91
-------
a". Enter street name and orientation, and "lane numbers
for each leg.
b. Enter the lane edge to receptor correction factor
determined from Figure 25 for the approach and
departure lanes on each leg.
6. Part IV-B (Assume that the receptor is located on the
departure side of each leg):
a. Repeat the procedure outlined in.5., above, only
assuming that the receptor is located on the
opposite side of the street.
7. Part V-A (Assume that the receptor is located on the
approach side of each leg):
a. Enter the street name and orientation, and lane
numbers for each leg.
b. Compute the corrected lane concentrations as the
product of the lane concentrations presented in
Part III, and the lane edge to receptor distance
correction factors presented in Part IV-A; record
these and the total concentration for each leg.
8. Part V-B (Assume that the receptor is located on the
departure side of each leg):
a. Enter the street name and orientation, and lane
numbers for each leg.
b. Compute the corrected lane concentrations as the
product of the lane concentrations presented in
Part III., and the lane edge to receptor distance
correction factors presented in Part 3V-B; .record
these and the total concentration for each leg.
9. Part VI-A .(Assume receptor is located on the approach
.side of each leg)-:
a. Enter the street name and orientation, and the lane
numbers for each leg.
b. Enter the total concentration for each leg from
Part V-A, in column a.
c. Enter the vehicle mix correction factor, f^, com-
puted for each leg in accordance with instructions
provided in Section IV-B, in column b.
92
-------
d. Enter the product of the total concentration and
vehicle mix correction factor (a x b) in column c.
e. Enter the estimated maximum 1-hour average back-
ground concentration (see Section IV.G) in column d.
f. Enter the sum of columns c and d in column e.
g. Enter the 8-hour correlation factor (see Section IV.F)
in column f.
h. Enter the total maximum 8-hour average.concentration
expected at the receptor, computed as the product of
columns e and f, in column g.
10. Part VI-B (Assume receptor is located on the departure
side of each leg):
a. Enter the street name and orientation, and the lane
numbers for each leg.
b. Enter the total concentration for each leg from Part V-B,
in column a.
c. Enter the vehicle mix correction factor, fvm> (same as
fyuj entered in column b in Part VI-A) in column b.
d. Enter the product of the total concentration and vehicle
mix correction factor (a x b) in column c.
e. Enter the estimated maximum 1-hour average back-
ground concentration (same as d in Part VI-A) in
column d.
f. Enter the sum of columns c and d in column e.
g. Enter the 8-hour correlation factor (same as f in VI-A)
in column f.
h. Enter the total maximum 8-hour average concentration
expected at the receptor, computed as the product of
columns e and f, in column g.
c- Step 3 - Upon completion of step 2, above, the following data are
entered for each location on the Hot Spot Verification Summary Sheet
(Form 5):
93
-------
1. The location and its assigned number .(see Section III.B.3.a).
2. The highest of .the two concentrations computed for each
leg in column g of Parts VI-A and VI-B of the Hot Spot
Verification Work Sheets.
2. Subtask 2-b; Hot Spot Verification at^ Locations Where Conditions of
Uninterrupted Flow Prevail
a. Step 1 - Prepare a sketch of each location to be analyzed on a Hot
Spot Verification Work Sheet"- Field Data (see Section III.B.3.b.); include
the same data as was indicated in Step 1 for Hot Spot Verification at
Signalized Intersections (see Section III.C.I.a.)•
b. Step 2 - The following pertains to the Hot Spot Verification Work
Sheet - Uninterrupted Flow (see Section III.B.3.d.). These sheets should
be completed for each location, "as follows:
1. Enter the appropriate data in the heading of the sheet.
2. Part I:
a. Enter the lane numbers* and direction of flow.
b. Enter the adjusted peak hour volume (winter 1977-78)
on line A for each lane.
c. Enter the lane capacity (vehicles per hour) on line B.
d. Enter the lane volume*tb capacity ratio, computed as
line A divided by line.B, on line C.
e. Enter the resulting lane concentration on line D, computed
from either Figure 26 (if the facility is an expressway)
or Figure 27 (if "the facility is an arterial), and the
volume to capacity-ratio (from line C) and the capacity
(from line B).
3. Part II:
a. Designate the side of the roadway that the receptor is
assumed to be located on.
b. On line A enter the lane edge to receptor distance correc-
tion factor based on data"from the sketch of the location
and the nomograph in Figure 28.
94
-------
c. On line B enter the receptor concentration computed as the
product of I-D and II-A; also, record the sum of the indi-
vidual concentrations.
d. Assuming the receptor is located on the opposite side of
the street (designate the side; e.g., west side of the
street) enter the lane edge to receptor distance correction
factor, again, based on data from the sketch of the loca-
tion and Figure 28, on line C.
e. On line D enter the receptor concentration computed as the
product of I-D and II-C; also, record the sum of the
individual concentrations.
4. Part III:
a. Indicate the side of the street on which the receptor is
assumed to be located.
b. In column b, first line, enter the total receptor concentra-
tion from II-A; on the second line, enter the total receptor
concentration from II-D.
c. In column b, enter the local vehicle mix correction factor,
f (see Section IVrB).
vm
d. Enter the corrected concentration computed as the product of
columns a and b, in column c.
e. Enter the maximum expected 1-hour average background concen-
tration (see Section IV. G) in coluiLn d.
f. Enter the total receptor concentration computed as the sum
of columns c and d, in column e.
g. Enter the 8-hour correlation factor (see Section IV.F) in
column f.
h. Enter the estimated maximum 8-hour average concentration ex-
pected computed as the product of columns e and f, in column g.
Ct Step 3 - Upon completion of Step 2, above, the following data are
entered for each location on the Hot Spot Verification Summary Sheet
(Form 5) :
1. The location and its assigned number.
2. The highest concentration computed in column g, Part III of the
Work Sheet.
95
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3. Subtask 2-c; Hot Spot Verification at Nonsignalizcd Intcrsg£tianjL
a. Step 1 - Prepare a sketch of each location to be analyzed on a Hot Spot
Verification Work Sheet - Field Data form; include the same data as was
indicated in Step 1 for Hot Spot Verification at Signalized Intersections
(see Section III.C.I.a).
b. Step 2 - The following pertains to the Hot Spot Verification Work
Sheet - Nonsignalized Intersections (see Section III.B.3.e). These sheets
should be completed for each location as follows:
1. Enter the appropriate data in the heading of the sheet.
2. Part I:
a. Enter the street name and lane numbers for the streets con-
trolled by STOP-signs, above line A.
b. Enter the adjusted peak hour volumes (winter 1977-78) for
each approach and departure lane, for each leg, on line A.
c. Enter the lane capacity for each approach lane (see Section
IV.E) on line B.
d. Enter the volume-to-capacity ratio of each approach lane
computed as the quotient of line A divided by line B, on
line C.
e. Enter the estimated cruise speed for each departure lane
(see Section IV.D) on line D.
f. Enter the lane concentrations on line E, computed from
the volume-to-capacity ratio (line C) and the capacity
(line B), utilizing Figure 29, for approach lanes, and
the volume (line A) and cruise speed (line D) utilizing
Figure 24, for the departure lanes.
3. Part II:
a. Assuming the receptor is on the approach side of each street,
enter the lane edge to receptor distance correction factor
(based on the site sketch and the nomograph in Figure 28) on
line A.
96
-------
b. Enter the receptor concentration for each lane on line B,
computed as the product of Part I.E and Part II.A; also,
enter the sum of the individual lane concentrations.
c. Assuming the receptor is on the departure side of each street,
enter the lane edge to receptor distance correction factor
(based on the site sketch and the nomograph in Figure 28) on
line C.
d. Enter the receptor concentration for each lane on line D,
computed as the product of Part I.E and Part II.C; also,
enter the sum of the individual lane concentrations.
4. Part III:
a. For each leg enter the computed receptor concentrations from
Part II.B and Part II.D, in column a.
b. Enter the local vehicle mix correction factor, f (see
Section IV.B) in column b.
c. Enter the corrected concentration, computed as the product
of columns a and b, in column c.
d. Enter the maximum expected 1-hour average background con-
centration (see Section IV.G) in column d.
e. Enter the total maximum 1-hour average concentration expected,
computed as the sum of columns c ar.d d, in column e.
f. Enter the 8-hour correlation factor (see Section IV.F) in
column f.
g. Enter the maximum expected 8-hour average concentration,
computed as the product of columns e and f, in column g.
c. Step 3 - Upon completion of Step 2, above, the following data are
entered for each location on the Hot Spot Verification Summary Sheet
(Form 5) :
1. The location and its assigned number.
2. The highest concentration computed in column g, Part III of
the work sheet.
97
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3. Subtask 2-d: Hot Spot Verification for Special Cases
Special cases can be considered to include intersections under police con-
trol, facilities where the nature of traffic is such that the peak hour
volumes represent a very high percentage of the ADT on the street (as a
minimum, about 20 percent), or facilities where high volumes occur
irregularly, such as at sports stadiums or other event-oriented facilities.
Analysis of these may more appropriately consider the maximum impact on
ambient air quality over a 1-hour period rather than the 8-hour period
discussed previously. The process in this case would be exactly the same
as that outlined for Task 2 except that the final computations would not
involve application of the 8-hour correlation factor, and the standard for
determining whether or not a hot spot was indicated would be 35 ppm rather
than 9 ppm. It is noted that the preliminary screening process is not
applicable to these special cases since it considers the 8-hour average
concentration only.
98
-------
REFERENCES
1. Highway Capacity Manual. Highway Research Board, National Academy of
Sciences, National Research Council. Washington, B.C. Special Report
No. 87. 1965.
99
-------
SECTION IV
ADDITIONAL SCREENING INSTRUCTIONS
This section provides discussion of a number of issues relevant to hot
spot screening. The intent is to clarify several points as well as to
suggest techniques which perhaps will result in an increased measure of
consistency in performing screening.
A. G/Cy
An important element in the screening of signalized intersections is the
ratio of the green time allocated to each approach, to the total cycle
length (G/Cy). For the preliminary screening process, G/Cy is "built
into" the screening curves. However, for the hot spot verification pro-
cess, 'G/Cy for each lane approaching a signalized intersection must re-
ceive careful attention.
The procedure for verifying hot spot potential at signalized intersec-
tions involves determining, first, the type of control mode utilized -
that is, whether the signal is fixed time or actuated. If the installa-
tion utilizes a fixed-time controller, the determination of the lengths
of both the green phase and total cycle, hence G/Cy, can be established
through records such as permits or design specifications, or by timing
the phases in the field. For actuated systems, the G/Cy for each approach
can be estimated by apportionment of the green time among the Individual
phases based on the critical volume demand occurring during each phase.
Where obvious differences exist in the critical lane capacities of con-
flicting approaches, the volume to capacity ratio (V/C) should be utilized
100
-------
in apportioning green time to account for these differences. For example,
if the critical volume, V of an approach is 400 vehicles and the capa-
city, C^, is 800 vehicles per hour (vph) , while the opposing critical
volume, V2, and capacity, C2, are 200 vehicles and 400 vph, respectively,
the "weighted" apportionment of green time for V traffic is:
(400) (400)
ZG Vi V2 V^ + V^ (400) (400) + (200) (800)
In general terms, the ratio of green time for phase i to the total green
time of a signal cycle involving n phases, is:
For all types of signal systems where actuated pedestrian phases are
provided, an estimate must be made of the extent to which these phases
are utilized, and their net impact reflected. Essentially, the impact
of pedestrian phases will be to reduce the total green time available,
therefore reducing the G/Cy for each approach. Field observations
should provide a sufficient basis for estimating the usage of the pedes-
trian phases in general terms such as: on call 10 cycles per hour, etc.
Special consideration must also be given to locations where continuous
right turns are permitted. If exclusive turn lanes are provided, the
procedure is to use Figure 24 for computing carbon monoxide concentra-
tions resulting from traffic utilizing the turn lane. Where free
right turns are permitted from a through lane, however, it is likely
that access to the right turn will occasionally be blocked by through
101
-------
traffic daring a red phase. In this case, Figure 23 should be used for
computing carbon monoxide concentrations resulting from traffic in the
lane, although an adjustment should be made to the lane's G/Cy to account
for its increased throughput capability attributable to the free right
turn. The basis for this adjustment should be field observations that
focus on estimating the extent to which the lane remains open to vehicles
making the right turn, during the approach's red phase.
102
-------
B. LOCAL VEHICLE MIX CORRECTION FACTOR
The nomographs developed for hot spot verification assume a vehicle mix
of 88 percent light-duty vehicles and 12 percent light-duty trucks. '
However, for actually verifying hot spot potential at a particular loca-
tion the actual vehicle vehicle-type distribution should be determined
and appropriate adjustments made to the concentrations computed from the
nomographs. This adjustment is made by applying a correction factor,
f , to the concentrations computed from the nomographs.
In order to determine the appropriate value for f the actual local
vm
vehicle mix must be determined. Essentially, this involves identifying
the relative proportions of four vehicle types within the traffic stream,
including:
• light-duty vehicles (passenger cars)
• light-duty trucks (up to about 6000 pounds GVW)
• heavy-duty, gasoline-powered vehicles
• heavy-duty, diesel-powered vehicles
The correction factor, f , is determined through the following equation:
i_r . ^
vm ~ 24.12 Idv' Idv ^Idt Idt ^hdv UJv' hddv
_2
where p,, = percent LDV's in the vehicle population x 10
p., = percent LDT's in the vehicle population x 10
p., = percent HDV's in the vehicle population x 10
p. .. = percent HDDV's in the vehicle population x 10
nddv
i, , = average emissions index for LDV's; = 22.5
Idv
i1 , = average emissions index for LDT's; =• 36.0
i, , = average emissions index for HDV's; = 114.7
ndv
i, ,, = average emissions index for HDDV's; = 28.7
hddv
103
-------
For areas where so-called "tail pipe controls" such as retrofit or in-
spection and maintenance are anticipated, adjustments should be applied
accordingly to account for reduced emissions rates. Since these types
of controls are often specific to a particular classification of vehicle,
such as retrofitting only HDV's or applying inspection and maintenance
to LDV's only, the adjustments should be applied only to the classifi-
cation(s) impacted. In applying the adjustments, the expected reduction
_o
in emissions (expressed in percent x 10" ) attributable to the control
measure, is applied to the emissions index for the vehicle category
affected. For instance, if a particular configuration of inspection
and maintenance is expected to be applied to LDV's and LDT's only, and
the expected reduction overall in emissions from each is 9 percent and
11 percent, respectively, the adjustments involved are:
for LDV's: Emissions index (i^dv) from the previous page is
22.5 grams/mile. Effectiveness of control measure
is 9 percent x 10~2 = 0.09.
Corrected emissions factor (i'ldv) ^3'
i'ldv = (ildv)(1>0 " °'09) = (22. 5) (0.91) = 20.5 grams/mile.
for LDT's: Emissions -index (ildt) from the previous page Is
36.0 grams /mile. Effectiveness of control measure
is 11 percent x 10~2 = 0.11.
Corrected emissions factor (
i'ldt = (ildt)(1>° ~ 0>11) = (36.0) (0.89) = 32.0 grams/mile.
To account for the effects of the inspection and maintenance, then, the
emissions indices i',, and i'
Idv
respectively, in Equation. (2) .
emissions indices i'ldy and i'ldt are substituted for i and
104
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C. REASONABLE RECEPTOR SITE
1. Definition of Reasonable Receptor
The following is an excerpt from a U.S. Environmental Protection Agency
report entitled Guidelines for Air Quality Maintenance Planning and
Analysis, Volume 9: Evaluating Indirect Sources.
Receptor Site - A location where it is of interest to
estimate ambient CO concentrations. In general terms,
analysis should center on reasonable locations in the
vicinity of that portion of the traffic network (e.g.,
parking lot, access roads, intersections) where the
combined impact of the proposed source and other traf-
fic is likely to result in the highest traffic demand
and/or most traffic congestion. Definition of "reason-
able" depends on the legal interpretation of the word
"ambient." "Ambient" is interpreted as meaning that
portion of the atmosphere, external to buildings, to which
the general public has access. The primary standards
for CO imply that reasonable sites are required to be
in locations to which the general public (note: not
necessarily any specific individual) has access. The
recommended procedure for selecting such sites is through
joint review by the reviewing agency and applicant of
maps and plans of the area and facility which are re-
quired as part of the indirect source or parking manage-
ment application. To clarify what might generally be
regarded as reasonable or unreasonable receptor sites,
a few examples are cited below. It should be strongly
emphasized that these examples only suggest what is
generally expected to be the case. If the review of a
specific application reveals that a site which may or-
dinarily be unreasonable is, in fact, reasonable in a
specific case (or vice versa) then, of course, the
specific ruling would supersede this general guidance.
a. Examples of Reasonable Receptor Sites -
1. All sidewalks where the general public has access on
a more or less continuous basis are reasonable
receptor sites.
105
-------
2. A vacant lot in which a neighboring facility is
planned and in whose vicinity the general public
(including employees if the neighboring facility
is not being built for the prime purpose of traf-
fic control) would have access continuously is a
reasonable receptor site.
3. Portions of a parking lot to which pedestrians
have access continuously are reasonable receptor
sites.
4. The vicinity of parking lot's entrances and exits
is a reasonable receptor site, providing there is
an area nearby, such as a public sidewalk, resid-
ences or structures (e.g., an auto service center
at a shopping center) where the general public is
likely to have continuous access.
5. The property lines of all residences, hospitals,
rest homes, schools, playgrounds, and the entrances
and air intakes to all other buildings are reason-
able receptor sites.
From a practical standpoint it is not possible to generate universal
guidelines that provide detailed instructions for determining the exact
location of a reasonable receptor. For the purposes of hot spot verifi-
cation the most practical guidance that can be given is to assume the
receptor to be located at the centerline of adjacent sidewalks or at
the right-of-way limit if there are no sidewalks adjacent to the facility.
The key is to keep in mind that the receptor should represent the loca-
tion proximate to the highway or street where the general public has
access.
2. Lane Edge to Receptor Distance
From Figures 25, 28, and 30, it is obvious that carbon monoxide concen-
trations diminish rapidly with distance from the emissions source. This
being the case, it is important to establish the proximity of the receptor
with respect to the edge of each travel lane on an adjacent roadway.
First, if the receptor is identified as being a sidewalk, the center line
106
-------
of the sidewalk should be considered as the actual receptor site. From
this point, the distance to the near edge of the traveled portion of each
lane should be determined and using these distances in conjunction with
Figures 25, 28, and 30, appropriate correction factors determined.
107
-------
D. CRUISE SPEED
From Figure 24 it can be seen that the cruise speed downstream of the
intersection must be determined in order to compute concentrations from
departing vehicles. Generally, cruise speed will be a function of the
type of facility, proximity of downstream signals and whether these
signals are coordinated, interference from pedestrians or other traffic,
roadway alignment, etc. Estimates of the downstream cruise speed, then,
can be made by categorizing locations according to the extent that fric-
tion can be expected in the traffic stream, and relating these general
categories to speed ranges. Table 1 suggests criteria for selecting
appropriate cruise speeds for use with Figure 24. Obviously, selection
of the cruise speed element is somewhat subjective; however, utilizing
the general criteria outlined in Table 1, in conjunction with field
observations and a general familiarity with the area being analyzed,
should result in a reasonable estimate of these speeds.
Table 1. CRITERIA FOR SELECTION OF CRUISE SPEED VALUES
General location
Central business district;
Fringe business district
Outlying business district;
Dense residential/
commercial land use;
Outlying and residential
residential/comroticlal
land use;
Operating characteristics
Much interference and fric-
tion from pedestrians or
parking and unparking vehi-
cles; closely spaced inter-
sections; individual vehicle
speed nearly always controlled
by speed of the entire traf-
fic stream;
Occasional interference and
friction from pedestrians
or parking and unparking
vehicles; nearby intersec-
tions occasionaly restrict
flow; individual vehicle sp>ecd
somewhat controlled by speed of
of entire traffic stream;
Infrequent Interference or
friction from pedestrians or
maneuvering vehicle*; no
interference from downstreaa
intersections; speed of Indi-
vidual vehicle mildly Influ-
enced by ipecd of traffic
streaa.
Cruise speed
range
(mph)
15 - 20
20 - 30
25 - 35
108
-------
E. CAPACITY
1. Preliminary Screening
In the preliminary screening process estimates of lane capacity are re-
quired for streets and highways where uninterrupted flow conditions pre-
vail or are assumed to prevail.
Lane capacity can be estimated from the expression:
C = 2,000 W TC
where C = lane capacity
W = adjustment for lane width and lateral clearance
T = truck factor
The appropriate values of W and T can be determined from the 1965 Highway
Capacity Manual. If. data is not available regarding the parameters re-
quired for determining W and T , it is suggested that national or re-
gional averages be used. These data can be obtained from agencies such
as the Automobile Manufacturers Association (AMA) or the American Associa-
tion of State Highway and Transportation Officials (AASHTO) for traffic
composition; and from state highway inventories or design standards for
physical characteristics such as lane widths and lateral clearances.
2. Hot Spot Verification
The same procedure is utilized for estimating lane capacity as described
above except it is reasonable to expect that the actual physical and
operating characteristics (lane widths, clearances, percent trucks and
buses, etc.) can be determined rather than assuming or estimating these.
109
-------
Analysis of the approach lane capacity of streets controlled by STOP
signs has not received wide attention. Research that has been docu-
mented indicates that the capacity of a STOP-sign controlled lane is a
function of the capacity and volume demand of the through street. From
this general observation, the following expression was developed to pro-
vide a means for estimating approach lane capacity:
C2 = (0.75)(C1 - Vx)
where £- ~ tne capacity of the STOP-sign controlled approach
C, = the average lane capacity of the major through street
in the critical direction.
V.. = average lane volume of the major through street in the
critical direction.
In the above, critical direction means the roadway direction with the
highest average lane volume to capacity ratio (V/C).
110
-------
F. 8-HOUR CORRELATION FACTOR
The screening guidelines incorporate techniques based upon the calculation
of 1-hour average concentrations of carbon monoxide from peak hour traffic
volumes. Because the 8-hour standard is more often violated then the
1-hour standard, it is necessary to provide a means for developing esti-
mates of the 8-hour average concentration from the calculated 1-hour
average.
Analyses of air quality data from a number of monitoring stations in
several cities in the northeastern U.S. were conducted in order to
determine whether a definite relationship could be established between
1-hour average and 8-hour average concentrations. These analyses were
based on examining the relationship between maximum 1-hour average con-
centrations, and maximum 8-hour average concentrations where the 8-hour
averaging period included the maximum 1-hour average. These analyses
indicated that the average ratio of 8-hour average concentrations to
1-hour average concentrations ranged in value from about 0.5 to 0.8, with
an average of about 0.7. Further, analysis of the relationship where
1-hour- concentrations were 10 ppm or more, indicated that this ratio was
slightly lower with with a range generally of from 0.6 to 0.7. Thus,
a value of 0.7 was selected as being representative of the 8-hour to
1-hour ratio. It is emphasized that if sufficient local air quality
data are available, these should be analyzed to determine whether some
other value representing the 8-hour to 1-hour ratio might be more appro-
priate for that location.
Ill
-------
G. BACKGROUND CONCENTRATION
Studies have indicated the existence of a background concentration of car-
bon monoxide occurring throughout urban and suburban areas as a result
of dispersion of the pollutant at or near ground level. Determination
of the actual value of the maximum expected background concentration
involves long term local monitoring as described in the Guidelines for
Air Quality Maintenance Planning and Analysis, Volume 9: Evaluating
Indirect Sources.
It is very likely that in many instances local monitoring will not be
possible. Owing to this a value representing background concentrations
was developed, based on limited analyses of data for three cities in
New England. The value determined, 5.0 parts per million (ppm), is based
in part on air quality modeling using a diffusion model (AFRAC) and
meteorological data covering a 1-year period. These analyses indicated
that the average maximum background concentration (8-hour average) com-
puted for 20 locations in each city ranged from 2.5 ppm to 5.1 ppm during
1973 to 1974. Extrapolating these figures to 1977 to 1978 would result
in a range of about 1.5 ppm to 3.1 ppm. Using the higher value, 3.1 ppm,
the maximum 1-hour average background concentration can be estimated
through the l-hour/8-hour correlation factor discussed previously. Apply-
ing this factor results in an estimated 1-hour average background concen-
tration of about 4.4 ppm or (conservatively), say 5 ppm. Thus, the 5 ppm
value is recommended unless data are available to develop specific local
background estimates.
112
-------
H. DEFINITIONS
Several terms used in this guideline are defined below to clarify their
intended meaning.
1. Complex Intersections/Special Cases
This term is used in the preliminary screening process and is defined
as an intersection where the volumes, turning movements, geometry, or
number of approaches, result in a signal cycle comprising more than two
phases. An intersection can be considered complex if pedestrian activity
is such that traffic flow is interrupted during most cycles by pedestrian
crossings.
A special case refers to either a signalized or nonsignalized intersection
where conditions are such that the preliminary screening technique be-
comes inappropriate for evaluating hot spot potential. Examples of special
cases include (1) signals used only for certain events such as during
peak-hours only, or during work-shift changes if the location is in the
vicinity of a major industrial or office complex; (2) where signals are
manually operated or pre-empted in favor of traffic direction by police
personnel; (3) where signals are utilized for pedestrian crossing protection
only; and (4) where police control is utilized at nonsignalized inter-
sections.
2. Congested/Noncongested Areas
These terms are utilized in the preliminary screening procedure to indi-
cate whether or not significant interference to traffic departing from
an intersection can be expected. For congested areas, downstream cruise
speeds will be fairly low (less than about 20 to 25 miles per hour) with
some interruptions occurring. In noncongested areas, however, few, if
any, interruptions to departing traffic will occur, and downstream cruise
speeds will be somewhat higher (at least 25 miles per hour).
113
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APPENDIX A
BASE MAPS DEVELOPED FOR THE SCREENING OF WALTHAM, MASSACHUSETTS
Presented in this appendix is a series of maps developed for use during
the screening of the City of Waltham. These were prepared by modifying
a set of maps provided by the Massachusetts Department of Public Works.
Included are the following:
Title
Figure numbers
Hot Spot Analysis Sites
Traffic Volume Count Locations
Traffic Flow Map
Figures Al-a, Al-b
Figures A2-a, A2-b
Figures A3-a, A3-b
A-l
-------
LEGEND
• SIGNALIZED INTERSECTION
• NON SIGNALIZED INTERSECTION
A MID- BLOCK LOCATION
OCA/TECHNOLOGY DIVISION •• A
HOT SPOT ANALYSIS SITES
WALT HAM, MASSACHUSETTS
NOV. 1975
FIGURE A-IA
A-3
-------
LEGEND
• SIGNALIZED INTERSECTION
• NON SIGNALIZED INTERSECTION
A MID-BLOCK LOCATION
GCA/TECHNOLOGY DIVISION
HOT SPOT ANALYSIS SITES
WALTHAM. MASSACHUSETTS
NOV. 1975
FIGURE A-IB
-------
LEGEND
A ATR COUNTS
• MANUAL COUNTS
• OTHER COUNTS
• VEHICLE MIX CLASSIFICATION
" COUNTS
GCA/TECHNOLOGY DIVISION
TRAFFIC VOLUME COUNT LOCATIONS
WALTHAM , MASSACHUSETTS
NOV. 1975
FIGURE A-2A
A-4
-------
\
ib»t "l-St * Tfi
h
Z
LEGEND
A ATR COUNTS
• MANUAL COUNTS
• OTHER COUNTS
I VEHICLE MIX CLASSIFICATION
COUNTS
GCA/TECHNOLOGY DIVISION
TRAFFIC VOLUME COUNT LOCATIONS
WALTHAM . MASSACHUSETTS
NOV. 1975
FIGURE A-2B
A-5
-------
\
EST. ADT SCALE
-25.0OO-
.—15,000-
5,000-
GCA/TECHNOLOGY DIVISION
TRAFFIC FLOW MAP
WALTHAM, MASSACHUSETTS
NOV. 1975
FIGURE A-3A
A-6
-------
EST. APT SCALE
5,000-
GCA/TECHNOLOGY DIVISION
TRAFFIC FLOW MAP
WALTHAM, MASSACHUSETTS
NOV. 1975
FIGURE A-3B
A-7
-------
APPENDIX B
EXAMPLES OF THE PRELIMINARY SCREENING PROCEDURE
This appendix provides examples of completed forms from a preliminary
screening effort undertaken in the City of Waltham, Massachusetts, as part
of the development of the preliminary screening procedure. Shown in this
appendix are the data sheets for 14 of the 51 separate locations analyzed;
included are five signalized intersections, five locations where conditions
of uninterrupted flow prevail, and four nonsignalized intersections. The
location numbers appearing on the Initial Screening Summary Sheet corre-
spond to the numbered locations shown on the Hot Spot Analysis Sites map,
presented in Figures A-la and A-lb in Appendix A.
B-l
-------
, SCREENING SUMMARY S!l
City/Town: __
Analysis By:
Approved By:
WALTI1AM
(OJJM)
State:
page _Lof Jo i
MASSACHUSETTS
(tUU)
Date:
Date:
(tiel.)
Location
15. Lexington St. at Totten Pond
Rd. and Bacon St.
18. Bacon St. at Dale St.
19. Bacon St. at School St.
22. Hammond St. at Columbus St.
29. High St. at Lowell St.
32. Main St. at Lyman St.
35. Lexington St. at Lake St.
37. Moody St. at Crescent
and Derby Streets
43. Weston St. at South St.
45. Route 128 at Main St.
46. Trapelo Rd. between Forest
St. and Waverly Oaks Rd.
47. Weston St. between
Route 128 and Eddy St.
48. South St. between Brandeis
University and Waltham
Hospital
49. Beaver St. between Forest St.
and Waverly Oaks Rd.
Type
Signalized
Intersection
Signalized
Intersection
Signalized
Intersection
Signalized
Intersection
Signalized
Intersection
Nonsignalized
Intersection
Nonsignalized
Intersection
Nonsignalized
Intersection
Nons ignalized
Intersection
Uninterrupted Flow
Uninterrupted Flow
Uninterrupted Flow
Uninterrupted Flow
Uninterrupted Flow
Hot Spot Indicated
or
Detailed Analysis Required
Yes
X
X
X
X
X
X
X
No
-X
X
X
X
X
B-2
-------
PRELIMINARY
City /Town: \\fF\LT\Af\
Analysis By:
Approved By:
SCREENING WORK SHEET- SIGNALIZED INTERSECTIONS
page
^ State: K\Fs^St;\c_l4V)<,. Yes; No; If yes. enter location on Initial Screening
Summary Sheet and proceed to next intersection; If no, proceed with Part IV.
Part IV Analyze each leg teperately on the forn, below.
*_
Designation
^^===--===^12
ii<
±
Adjusted
AW
(1977-73)
X
c
Conf Ifcur-
at ion
X
Street:
d
Ad |UM I'd
AM
(1977-7B)
S: rcct :
e
C(»nl 1 Dur-
ation
Lc
t_
Figurt/
curve used
T.
z:
i.
Hot spot
Indicated?
; •
Street:
h
Adjusted
ADT
(1977-781
Street:
l^
Conf i gur-
le
J.
Fig""/
1^
i:
V_
Hot «;.ot
7 T
Part I Location:.
Part II Congested Area? Yes;
. X
Mo
Fart III Couplex Intersection or Special Case?.
-Yes;
. X
Simraary Sheet and proceed to next Intersection; If no, proceed with Part IV.
Fart IV Analyze each leg separately on the form, below.
Ho; If yes, enter location on Initial Screening
Leg under «n»lysit
£
Devlgnaclon
O._le. (botvC)
I^r==— ==rilll
$OOC)
X
8000
c_
Conf 1 yur-
• tlon
^\.|^vJ
X
lt.|iW
Strertl ^1 fl- C O r\ Irt: V4
d
Ad|u!i(i-d
APf
(1977-78)
8000
e
Confltur-
atlon
2L/2W
£
Figure/
curve used
*'b
E.
Mot ipot
Inriic«tcti7
S10
s\ tei: S
h^
Ad )uited
ADT
(1977-73)
8000
i
Conf 1 $ur-
at 1 on
H./ZW
X
FlRure/
curve used
z-e>
v_
Hot ipoc
Indicated?
NO
Street: 0 °- \ * Ur: W
3000
2L/1W
l-B
MO
B-3
-------
PRELIMINARY SCREENING WORK SHEET- SIGNALIZED INTERSECTIONS
page
City/Town: V; ft L"T y\
Analysis By:
Approved By:
(OUM)
of
State:
5 IXC HU
(ttcl.)
(titl.)
Date:
Date:
Part I Location:_2JLi£±_
Part II Congested Area? Yea : K Ho
Fart 111 Complex Intersection or Special Case? Yes; * No: If yes, enter location on Initial Screening
Sumnflry Sheet and proceed to next intersection; if no, proceed with Part IV.
Part IV Analyze each leg separately on the forn, below.
*_
gn on
Sc_Kool £/i«3
School W/Ucj
^^^===-^==^1^
Bo-corx fbotK)
b
AdJuTtcd
ADT
^000
$000
X
BOOO
c
Conf Ifcur-
a i on
7.L/IW
ZL/^
X
7.L|?W
Sc rcet :
d
Ad lustt-J
*rc
8000
2000
St rr OL :
^000
2> a-c o> v
e
CunUfcur-
a ^ on
ZillW
tL/ZW
^ C. K o t.
1L/1W
S Lc
f_
Ficurc/
curve use
i-e>
a- &
\
l-B
X: __H._
S_
Hoc 3 pot
n ica cc .
^S
KO
.. £
-ies
Street :
h_
Ad justed
ADT
oOOO
^GOO
S:rcot :
Sboo
(^
o\ ,,.
1-&
.: S
X
Hot i^ot
Y£^=
NO
,. vy
xe^
Part I i~.n~.. U^m^ovxA ^- Tr\ or>-!V Li-z: \iO^-*\
d
ATT
(1977-7S)
b'OOO
e
Cent Lfjr-
^L/^w
Figure/
1 6
6.
llot ipot
MO
<;, rr. , • C oU-t-V-"-! 1r-:\^«^-^i.
$000
'iv.Uv/
1 C>
NO
Street : t< a:
h
Ad ji.jred
Al'T
(1977-78)
Configur-
ation
J.
curve us«d
-
St rc»-t : | ,.c .
B-4
-------
PRELIMINARY SCREENING WORK SHEET- SIGNALIZED INTERSECTIONS
page _£Lof
City/Town:
Analysis By:
Approved By:
(o*»«)
(UM)
State:
(tlcl.)
Date:
Date:
Part
ating. V-A««.\N
Uov,<.lV S
Firt II Congested Area? Ye«: X No
P«rt III Coaplex Inter.ectlcm or Special Case? Yes; * No; If yes. enter location on Initial Screening
Sunraary Sheet and proceed to next Intersection; If no, proceed with Part IV,
P»rt IV Analyze each leg seper«tely on the form, below.
Leg under analysis
Designation
Lowell (bo-tK>
N
JII^^^^"^^111^^
WxoK fbcAV^
b
Adjusted
AD:
(1977-73)
1000
C
Conf lyur-
a c ion
1L(ZV/
Xll^xC
nooo
IV. |XVJ
Croi9-»cr«et data
Street: tAvcvVx Left: \?o"t^
d
Ad iuMcd
APT
(1977-78)
\~t OOCl
e
1L/ZW
£
^-B
Slr,.ct. L^vVV Le
•jooo
"J. *- | tW
i-a
s.
Hot spot
HO
.. bolVs
ve*
Screec: Lfa:
Ad jiuted
ADI
(1977-781
Confitur-
JL
Street: I*
Part I Location:.
Part II Congested Area?
No
Part III Complex Intersection or Special Case? Yes; No; If yes, enter location on Initial Screening
Sunaary Sheet and proceed to next Intersection; If no, proceed with Part IV.
Part IV Analyze each leg seperately on the form, below.
Leg under analysis
Designation
^^r=— =crd2
b
Adjusted
ADT
(1977-78)
X
c
Configur-
ation
^x^
Crofi-itreet «lata
*;r reel : U-e:
d
AJ|u.«li.-il
ACT
(1977-78)
e
Ci-n(ltur-
Jtlon
curve usrii
E.
Hot spot
Indlotcd1
SI «-•"" ' ! -.::
Street: lee:
h
Ad justed
A IT
(1977-78)
Conf icur-
ot Ion
JL
curve csed
Street : TV
I'ot «?ot
Indlc.tfd!
B-5
-------
PRELIMINARY SCREENING WORK SHEET - NONSIGNALIZED INTERSECTIONS
- - — ~ ~ page "_
City/Town: w f\ LT H ft. N\
State:
Analysis By:
Approved By:
(tlcla)
(tltla)
t -TT,
-------
PRELIMINARY SCREENING WORK SHEET - UNINTERRUPTED FLQW
Analysis By: _
Approved By:
State;
(cut.)
page J>_of
Date:
Date:
(tltU)
_•_
r.ciutr
Route. \13
Tro.pt\o fkck
We^tois ^t
SoutK 'it'
B eo.v^ r St..
_^
Loccclon
^ EJlA^ ^-t
Pjftvv. fey-a-r.cl.ev5. U^w ^ Ho^p\\.&.\
Rxi-VN, Foftst £ Wft.w.fr\M Oal^S
»
e_
Adju.t.d
ADT
(1977-78)
S^OOO
21)000
2.8000
\OOOQ
n ooo
£
Conf Igur-
•3L./CX.
ZU 1 P,
^u/A
tL/t\
tL/(\
a
Cic.
l«n«
\15O
1 800
1 QOO
1700
iBoo
f.
Hoc Spot
ves
ye^
Y£S
MO
WQ
B-7
-------
APPENDIX C
EXAMPLES OF THE HOT SPOT VERIFICATION PROCEDURE
This appendix provides examples of completed forms from a hot spot verifi-
cation effort undertaken in the City of Waltham, Massachusetts. Shown in
this appendix are the data sheets for the verification of the eight loca-
tions shown on the Initial Screening Summary Sheet in Appendix B, as having
hot spot potential.
C-l
-------
City/Town: Waltham
Analysis By:
Approved By:
HOT SPOT VERIFICATION SUMMARY
State: Mass.
(ctel.)
(tltU)
page
of
Date:
Date:
Location No,
15
19
29
37
43
45
46
47
Location
Lexington Street at Totten Pond Road and
Bacon Street
Bacon Street at School Street
High Street at Lowell Street
Moody Street at Crescent and Derby Streets
Weston Street at South Street
Route 128 at Main Street
Trapelo Road between Forest Street and
Waverly Oaks Road
Weston Street between Route 128 and Eddy Street
Maximum 8-hr.
Ave. Concentration
27.7
9.6
8.9
14.3
8.2
17.0
8.0
9.5
C-2
-------
HOT SPOT VERIFICATION WORK SHEET - FIELD DATA
City/Town:
Location:
ST.
Sketch of location and notes:
<
r>
LEXINGTON
15-
By: 7?A1
Date. 2<
.
XT
A
/
t-
A/,
c-3
-------
HOT SPOT VERIFICATION WORK SHEET - SIGNALIZED INTERSECTION
page I of "3
City/Town/:
By:
Intersection: LCXIKGTOM £* P>ftCOt4 Date: »o
rf/iT
I. PEAK 1DUR TOLUMES: Enter Una Kunhxri (froa sketch) snd pe«V hour volumes for vlnter 1977-78
(froa dat» eheets) .
lrtlt ritct ioa L«i
LeX\NGTO,N M/C^
LGXtNfiCivl 3)6
-BlXCGN
"TOTTCM PC fv(5
?e*k Rour Volueci
Approach Line Ho.
l
G^o
^GO
-110
•53C-
^
'•i
-------
HOTjjPOT VERIFICATION WORK SHEET - SIGNALIZED INTERSECTION
Intersection: L(rXINGTo^(g p,(\cc,4 City/Town/:
page 2 of
IV-A. LANE £DCE TO RF.CETTOR DISTANCE CORRECTION FACTORS: Enter lino edge to receptor distance correction
factor for each lane (obtained froa Figure No. ) »s»Lnlng receptor Is on the approach side of
each leg.
Xotirif ctlcm L*j
LeAlNOTON N/ft
LEXINGTON 5| G
6f\COM
ToTToN PC MO
Dlitmc* Correction F»cton
Approich L*n« X«.
/
i.i?
I. *i
(. ^T
j- •^^
7.
M $>
1.1?
(.1?
M?
Dtpirture L*n« Ho.
z
I.C'3-
(-6V
l-o ?
(
-OG
.9C-
l.c^
.OC,
17-B. LV:,- EZCE TO RECEPTOR DISTANCE CORPJCTION FACTORS: Enter lane edge to receptor distance correction
factor for each lane (obtained frora Figure No. ) nssralng receptor li on the departure side of
each Jjeg.
Latenectlon L
1.
7. 1
/Z.'i
'i.b
l.*
Departure Lint No.
2.
1-2.
i.l
/-I.
/
'•3
'•3
/-5T
/-I
Total
ZC.^
^o.t)
1?.?
n-X
C-5
-------
HOT SPOT VERIFICATION WORK SHF.ET - SIGNALIZED INTERSECTION (continued)
page 3 of
Intersection: UXINC.TE* g QfvCo^ City/Town/: V
V-B. RICETTOa. CONCEiTTATIONS ATTRIBirrASLE TO EACH UKE: Enter the concentration froa each lane corrected
for Ian-- «dge to receptor distance; this U computed ai the product of l.na concentration! (fro= III.
above) a^d the corresponding lane edge to receptor dlicsnca correction factor (froa IV-B, above);
•ssuoing receptor it on the departure side of each leg.
Intiroctlon L«i
Approach
Lini No.
?n«
Dep^rtur
Lune Ho.
Tot'l
VT-A. FINAL COX? tflAT IONS FOR MAXIMUM 1-HR AND 8-HR AVERAGE COSCEiTRATIONS: Enter the follovtng data:
(1) receptor concentration (frm V-A, above) In colunn a; (2) fv,3 (froo data sheet) In column b;
(3) background concentration (5ppa unless dcteralned otherwise) In column d; «nd (4) 8-hr
correlacLoa factor (0.7 unless deternlned otherwise) in column f. Compute concentration! as
•nova in coluani t, c, and g. Atauae receptor it on the approach side of ««ch leg.
Rtcsptor
COQC.
Corrected
Cooc.
(a x b)
B.cV-
jround
Cone.
Tot«l
1-hr «ve.'
Cone.
B-hr.
CorreUt.
EJC. 9-hr
Avt. Cone.
(e x I)
S.o
Zo.c
I-IC,
l-c4
i G . CJ
It. I
Vl-B. FDCAL CCXPUTATIDNS FOR KMOM'JM 1-HR A:,T) 8-HR A\TKAGE CONCENTRATIONS: Enter the following datm;
(1) rece-ptor concentration (fros V-B, above) in column a; (21 f%_, (fron data sheet) in column b;
(3) background concentration (5ppo unless determined otherwise) in column d; and (4) 8-hr
correlation factor (0,7 unless determined otherwise) in column f. Compute concentration! «»
• hovu Ln. columns c, e, and g. Assucio receptor i« on the depsrture side of each leg.
IoC*n«cttoa L«g
•
Ccxrputed
ticcptor
Coac.
b
*Y»
e
Com c 1 1 d
Cone.
(« « b)
t
I.cV-
groynd
Coac.
4
Tottl
1-hr ive.
Cone.
(c + <))
f
8-hr.
CorreliC .
Flccor
1
tit. 8-hr
Ave. Cone.
(• x O
C-6
-------
HOT SPOT VERIFICATION WORK SHEET - FIELD DATA
City/Town: __WALTHAM . MA.
Locati6n:
O'- C*' OC^»oC O^T
By; TPAf
Date:
Sketch of location and notes:
SCHOOL
J -*
0
Q
/fw
M
X
o
d\fj
O
<0
Q
JT
0
O
— '
75
v
A
C-7
-------
HOT SPOT VERIFICATION WORK SHEET - SIGNALIZED INTERSECTION
page 1 of 3
City /Town/: yjt\LT
By: f\HP\COM S/fi
0, (\ c c r-I M / (5
ScKot c (e/6 -- w/a)
fc*V Hour Volu»«i
Approach L*r« Ho.
1
•L-? o
Z^o
Z70
Ot;irCur« LJRC Ko.
I
-2-70
1^0
Z-70
II. AVERAGE G/Cy AM) CRUISE SPEED: Eater average G/Cy for approach lanes (froa <
*•
1
Average Crutit Speed
Dep*rtur« Lane No.
/
•jo
"iO
vC
III. RZSULTDJG LAKE CONCD.TRAnOKS: Enter lane concentrations for approach l«ne. (obtained froa
Figure No. ), and departure lane concentrations (obtained froa Figure Ko. ).
Inttr««ctlon L<|
BACcr^ b/ft
P,ACC^ /V/B
S c Hccc.
Co«?uCed L«n« Conc«ntr»tloni
Appro«ch Line Ho.
/
•T-l
^.M
G.t
Depjrture Ljn« Ho.
1
1-0
.^
(-0
C-8
-------
HQT_SPQT VERIFICATION WORK SHEET - SIGNALIZED INTERSECTION (continued)
page 2 of "V
Intersection : JVWcJNL_^__icJMc c_c. City/Town/:
IV-A. LAM; EDGE TO RECFTTOR DISTANCE COmcnOH FACTORS: Enter lane edge to receptor distance correction
factor Cor each Une (obtained froa Figure No. ) issuing receptor Is on the approach aide of
each leg. -
lnt«ri«cclcm L<(
BrXco/v S/n
ftACCM N/ft
SCHOOL.
/
1- ^
'- >1
>• )*.
Approach
Urx No.
D-rpjftur
r L*nt Ho.
1
1. 1?
(. iV
j.i?
IV-B. L.\M! EDGE TO RECEPTOR DISTANCE COPJIECTION FACTORS: Enter lane edge to receptor distance correction
factor for each lane (obtained from Figure No. ) assuming receptor if on the departure aide of
eacn leg.
Interjection Ug
Dittince Correccioa ficcor
Approach Lin* No.
f
V-A. RECEPTOR CONCENTRATIONS ATTRIBUTABLE TO EACH 1AME: Enter the concentration fron each lane corrected
for lane edge to receptor distance; this IB computed as the product of lane concentrations (froa III,
above) and the corresponding lane edge to receptor distance correction factor (froa IV A, above);
assuming receptor la OD the approach side of each leg*.
Iattr«ecttcn l«g
P>f\ccr/ S/0
ft A c o fj H/R
Sc H ecu
Corrected L*nt Conceotl •« t ion*
Ap?ro«ch L*n« No.
1
G. 7
$,?
3.0
DcpirCure LJnf No.
1
M
i. C
I.I
Totil
7-0
d S
'M
C-9
-------
HOT SPOT VERIFICATION WORK SHEET - SIGNALIZED INTERSECTION (continued)
page 3 of 3
Intersection: B/\c.c^ @ SC.IAOQI City/Town/:
V-B. RECEPTOR COHCEriRATIONS ATTRIBUTASLE TO EACH LANE: Enter the concentration from each line corrected
for lane edge to receptor distance; this 1. computed n the product of lane concentrations (fro= III,
above) and the corresponding lane edge to. receptor distance correction factor (froa IV-B, above);
• •aiming receptor is on the departure aide of each. leg.
lotiritctloti L*i
Approich
Un. Ko.
Depirtur
t Line No.
Total
VI-A. FINAL COMPUTATIONS FOR MAXIMUM 1-HR AND 8-HR AVERAGE CONCENTRATIONS: Enter the following data:
(1) receptor concentration (from V-A, above) in colunn a; (2) f^ (from data nheet) in column b;
(3) background concentration (Sppm unless determined otherwise) in column d; and (4) 8-hr
correlation factor (0.7 unless determined otherwise) in column f. Compute concentrations aa
ahovn in columns c, e, and g. Assume receptor is on the approach aide of each leg.
Intersection Leg
BKCCM "•>/&
B(\CCM N /e>
SCHCC^ (^E/O - W/fl)
•
Computed
Leceptor
Cone.
7-9
6.F
9-1
b
fva
/.C<*
l.W
.1$
c
Cone.
(• x b)
2-1
7.|
*••>
d
Cone.
?-c
s,o
S.c
«
Tot.l
CotLC.
(c + d)
Ci. I
It- 1
O-T
I
8-hr.
r«ctor
. 7
. 7
.7
i
tit. 8-hr
(e x O
9-1
*.*
*3-fo
VI-B. FINAL COMPUTATIONS FOR M/\XIMUM 1-HR ANTI 8-HR ANTRACE CONCENTRATIONS: Enter the following data;
(1) receptor concentration (froa V-B, above) in column a; (2) f^ (from data aheet) in column b;
(3) background concentration (5ppaj unless determined otherwise) in column d; and (4) 8-hr
correlation factor (0.7 unless determined otherwise) in column f. Compute concentrations aa
ehown in columns c, e, and g. Assume receptor is on the departure side of each leg.
Inttriictloo Leg
•
Computed
Leceptor
Cone,
b
*v.
C
Corrected
Cone.
(• « b)
d
B«ck-
ground
Cone.
•
Total
1-hr «ve.
Cone.
(c + d)
f
8-hr.
Correlit.
Factor
S
Ejt. 8-hr
Ave. CODC.
(• * O
C-10
-------
HOT SPOT VERIFICATION WORK SHEET - FIELD DATA
City/Town:
Location:
By:
Sketch of location and notes:
2 a
[-.'
G)
f**.l.i-> C
kJ
^
0
0
o
o
o-
0
£M
C-ll
-------
HOT SPOT VERIFICATION WORK SHEET - SIGNALIZED INTERSECTION.
page 1 of
City/Town/: y\y (\t_T BiXr-A By: (\v\^ __._
Intersection: H \ G. rA (? Lev/ e n Date: (Q lit h ^
I. PEAK HOUR VOLL.TCES: Enter Una Kunhn>r« (froa «ketch) and peak hour volumes for vlnter 1977-78
(froa data sheets).
lnt«r*ccCloa L«g
H 1 0 H W/6
H t c- u e/fe
Ql OlfH Tl CA l~ \
Ptik Rour Volueet
Approach L^n« Wo,
1
•i-7*
Dtpirture Lint No.
t
•b-75"
II. AVTP^GE G/Cy AlfD CRUISE SPEED: Enter average C/Cy for approach lanej (froa data sheets) «nd
average cruise apeed for departure lane«.
Intcritcttoo L«i
HIGH
Avtrtga C/Cy
Approach L*rv« Ho.
(
.tl
Departure Lfln« No.
/
30
III. PJ:SULTl:;C LANE CONCEITRATIONS: Enter lane concentrations for approach lanes (obtained from
Figure So. ), and departure lane concentrations (obtained froa Figure No. ).
Inttrltctlon L»i
H (G H
Computed L«n* Conc«ntr»C Ions
Approich L*ne Ho,
(
^.(*
Departure Lina No.
i
i. A
C-12
-------
HOT SPOT VERIFICATION WORK SHEET - SIGNALIZED INTERSECTION (continued)
page 2 of 1>
._..
-------
HOT SPOT VERIFICATION WORK SHEET - SIGNALIZED INTERSECTION (continued)
page 3 of J>_
Intersection: Hlt.>-i & Lcu.e<.t_ City/Town/:
V-B. P£CEPTOR CONCerrRATIONS ATTRIBUTABLE TO EACH LAKE: Enter the concentration froa each lane corrected
(or lane edge to receptor distance; this U computed it the product of lane concer.tr.t loni (fro= III,
«bove) and the corresponding lane edge to receptor distance correction factor (froa IV-B, above);
assuming receptor it on the departure aide of each leg.
Approach
Ltna Ho.
Depirtur
t t-»n« No.
Todl
VI-A. FINAL COMPUTATIONS FOR MAXIXUM 1-HR ALT) 8-HR AVERAGE CONCENTRATIONS: Enter the folloving data:
(1) receptor concentration (froa V-A, above) in column a; (2) fra (from dat« sheet) In column b;
(3) background concentration (5ppa unless determined otherwise) In column d; and (4) 8-hr
correlation factor (0.7 unless deternlned otherwise) in colu-n f. Cocpute concentrations «»
shovn in columns c, e, and g. Assme receptor is on the approach side of each leg.
IntiritcttOQ L«g
H v e-i tA
a
Computed
Cone.
7.t
b
-------
HOT SPOT VERIFICATION WORK SHEET - FIELD DATA
City /T o wn: WAI T^aw MA
— - ' — ' ' [ _ _- / ' •
/f /
Location:
Srs.
By:
Sketch of location and notes:
* 5-
u~
1
5~*
,
C-15
-------
HOT SPOT VERIFICATION WORK SHEET - NONSIGNALIZED INTERSECTION
page 1°f
City/Town:
By:
Intersection: MGoQX
CC.€SC€MT OCR.tW STS .
Date:
Type of Control: _ ^all-way STOP; _A_1 or 2 -way STOP; ___YIELD; _ None;
Street Controlled: CR£Sc£^T 4 OGR.QX
I. BASIC COMPUTATIONS:
ICM
1977-78 (Ito-a data theets)
C. V/C: Entec V/C /or approach lanei (cooputed a»
• 1 A 7 3. abcvr)
speed (frc"a cica iSeet*)
I. L"J.<. OON'CC.TiATIONG: £.Tt«r L»ni ccmcintr»tloo»
cocpucad froct A, C, and D, abov« , And 71g.
Leg: <
Approach
\
i'1.0
AlO
,30
x^
104
_&esc
Lane Ko.
X
e.fWT
D«p«rcure
^^^ ^^
^^,
X
'
L*n« Po.
I
'i^O
^v. ^^-
^-^
X
2.b
1-7
Lc5: <
Approach
i
.fc
^IO
.•J7
X
i-li
aeaaY
^•na No.
X
D^pirtur
"^x»^^ ^^-^
^x.^
X
r L*n« No.
1
-------
HOT SPOT VERIFICATION WORK SIIEF.T - NONSIGNALTZED INTERSECTION (continued)
page 2 of
City/Town:
Intersection:
V
{
Street Controlled: CRnJM 1-HR AND 8-HR AVERAGE CONCENTRATION
Intersection Leg:
N
It«
A. TIKM 0?>777ATTCNS 05 1-H3 ANO S-H* AVT3ACE
OCNCEX7WTIOSS: Enter tN; following; (1)
«ax?'jTATio:.ps or I-R?. A NO S-HX A \TRACE
CDXCCC?,\TICNi; Erter the follovlr.j; (1)
total receptor concer trador.i (frc^a Il-fl
• nd 1T-D, above) in colc=n a; (2) f^ (froa
ilati iheetj) In colczn b; (3) bacxf,rou^ « c'ecerolr^^ other-
vile) In col u2_n d; (i) 8-hr correlation £ic-
tor (0.7 ur.lejj ot^ervl^e dcCerrlned) In
colvrra f, Co^uce flr.al con"cer.:r«tlon» a •
Loci tioa
(i creet-
f\ o O r o
a
C«=puce
C- V
d
B.cV-
Conc.
s.o
.
Toc»l
Cone.
(c + d)
7-G
t
8-hr.
Victor
O ~7
s
Eit. «-hr
(• x O
5."^
G-17
-------
HOT SPOT VERIFICATION WORK SHEET - FIELD DATA
City/Town: /VX^TV^AI , M.^ By: 7/°///
Location: M
-------
Il°-I-SIigT_VERIFICATION WORK_SHEET - NONSIGNALIZED INTERSECTION
page 1 of 7...
City/Town:
Intersection: _y/EsrrM ST Q
Type of Control: all-way STOP; X.I
Street Controlled: SOcT^
Date: 10/27./7$'
STOP; YIELD; None;
I. BASIC COMPUTATIONS:
Itr.
19)7-73 (Ir.-i did ihte t>)
B. LANE CAfACin: tnt«r l.n< c.paclc, of .ppro.tj,
Uncs (fro-> data iV-eta)
* • A £ B . tb
X,
II. CORRECT FOR LANE EDGE TO RECEPTOR DISTANCES:
Assume receptor is on
side of street
lt»
1. LANE t:CE TO P.£CE?TD» D1STASCE CORjl-
tCTJOK TACTCP-S: Enttr lint tdgi to
1. fjxr?7oz CO:.CC-;ATIONS ATTRIS'JIAJLJ
Cr.ctTOJ, cOQpuCed •• ctv« product o£
I-£ 4aJ II-A, ibovt
L«B:
Approach
/
1-32
<>.-!
SO
LJ n t No,
^-\\
ST
Ll.,e Xo
/
/.io
/-3
TOTAL
V
/ \
7.*
Lrv .
A^p TOJ ch
-jn e No,
DC? irtur*
LJ-C >'3.
TOTAL
V
/ \
Assume receptor is on.
side of street
It«
C. UNt EWE TO FECtTrJR DISTANCE CORK-
ICIIPM fACTJIli: Cntfr Unc tdgr to
rtccptor dlit*nc« correction decor*
[or cJch Ur.t (obtJined (ro« flj. )
D. (LtCETTOR CC.NCC.TFATIOKS ATTRIBUTA HI
I'.'t^'il"'".^." ^ PrCMlUCl "
Lfg:
Approach
L.n« No.
fv-pi r tu r
Line No.
TOTAL
Lr,-
Apprcich
Jnc X-i,
^rrTCMr
L-nt S>.
TOTAL
C-19
-------
HOT SPOT VERIFICATION WORK SHEET - NONSIGNALIZED INTERSECTION (conLinucdj
page 2 of
City/Town:
W (\LTHF\M
Intersection:
_ST & SOOTH sT.
Street Controlled:
S. ft oT H $T.
III. FINAL COMPUTATION'S OF MAXIMUM 1-HR AND 8-HR AVERAGE CONCENTRATION
Intersection Leg:
S' 0 c T H S I
Icca
i.. ITXC. COMPUTATIONS OF 1-H3 ANT S-H.1 AVERAGE
CONCENTRATIONS: Enter cSe follovlr.g; (1)
«od II-D, ibove) In column i; (2) f^ (froi
h 1 ' '^
OQ t-oth aides of icreet
Receptor
(itrett-
• l
I
(• x n
?^
Intersection Leg:
Itea
A. FIKM. COGITATIONS CF 1-KR AND 8-HR AlTJl^CE
CONCENTF.XTICNSr Enter tSe following; (1)
tot*l receptor cor.ccr. cricions (froi II-B
«nd 11-D. »lx>vp) In coli^n *; (2) f^ (froa
die* iSeets) In colir--* b; (3) background
oonc«atr«tlon (5??= unleji det«rr:Inc4 other-
vlie) in col uz_i d; (i) E-hr correl»cion fac-
tor (0.7 VJT.UJJ pt.'-crwljc dcc*rzlne
-------
HOT SPOT VERIFICATION WORK SHEET - FIELD DATA
City/Toun; /Vu7>n.^ MA. ^^ By: TPM
Location: /?ouTf /2<3 Qer^tcJ MAI* ' A/ftrjo $V.J,
Date- 2
-------
HOT SPOT VERIFICATION WORK SHEET - UNINTERRUPTED FLOW page 1 of
City./Town: \/V (\LT HPstA , By: (NBC.
Street/Highway Section: U-V ROl'TE 116 ((?-> MlMN ST.Y Date:
I. F.ASIC CWJPUTATIONS:
lie-
SCVlTH bound l.n. No.
1
HO \VTtA- bound Lint Ko.
A. WLi.~^ZS:E>t«r pea* hour volume* for vtncer . ~. e, ^ • ,1 r, s\ i / t^ s-. • - i /-. i i-* x-^
1977-73 (fr.--. ,:.» .hrct.) 'CiC '"^C i ^ 0 O (•>-I 0 {4CO
J. LAXE CAPACITY: Enter Une cap«clty (Iroa d«t.
,h,et.) . t 7 "7O 1770 17 7C I f 7 7C I ( 7 7 O
C. V/C: Enter V/C for e«ch Une (A -r S, above) / I .-> i o O O
• Ol .3T-J .J*^ .J/
Ctx=?uted fron A jnd C. ibove, .id Figure Z* ' "r*
II. CORRECT FOR LAME EDGE TO RECEPTOR DISTANCES:
Assume receptor is on \V £ *:> 1 side of street
!30^ \ H bound Lane No
Itea
z.
A. LA.\T EZCE: TO F^CCPTOR DISTAN'CE COR.^-
tCTIO:f 7AC70F-S: Enter Unc td^c to — , * ^ A p — .- -^ i -^
receptor distance correccton f.icccr» » ' * »^3J .Vj^ ,J>O ,o '*
for each line (obtained fr/ct: Fif;. )
TO L^Ca IA:."!: Enter corrected CJP.CCQ- i C\ T A
tr»clon3, co^utcd ** the produce oi. \' ) •*. • Q
I-D md 11 • A , *ao"/«
Assume receptor is on ^ side of street
.__ bound Lflno No
c. L^:CI HXE: TO pj:cr?TX)R DISTANCE COF^-
ECT10N rACTOrJl: Cn:cr l^nc cJcc to
receptor distance corrcctlun factor*
for «Jch Uno (obt^ircd frca F1&. )
•IX RICirrOR CONCC»"Ti\TICNS ATT^aBl/IASLE
TO EAGi LAM: Enter corrected concen-
tration*, coajutcd AI ih« product ol
1-K *nd II-C. *bov*
l^-GO 1^>^C:
no
770 /77C
/ T7C
.•5k
- ft
bound LJ ne No,
TOTAL
.40
l.o
TOTAL
III. HKAL. COMPUTATION'S OF MAXIMUM 1-HR AND 8-HR AVERAGE CONCENTRATIONS
Itea
Loc* tlon
(ttree t-
• ide)
Co-spaced
Cone.
Cone.
(* x b)
ttck-
g round
Cone.
Totil
l-hr iv«.
Cone.
(c + d)
8-hr.
Cor re 1«c.
factor
EiC, 8-Sr
Ave. Cone.
A. riKvt COGITATIONS OF l-!!R AN"D 8-HR AVE?ACC
CCNCCNT PAT ION'S: E.Ttrr t rwr following; (1)
toul r*crpcor concfntntlon* (!rc-a II-5
ind II-D, «bjve) In column •; (?) f.^ (froa
dground
nU
v 1 • r ) In c o 1». -. n d; (^) fl-hr correlation fit-
tor (0.7 ur 1 e »i ot! f rvl »• dct^rcincd) In
colur.o f. Co-py t« Ilnil contcntntlon* *i
»Novo la c olurri t. •, J^J j, (or r«cfptor«
PQ both i lilei o£ «tr« f c
l.U
S.O
0-7
n-o
C-22
-------
HOT SPOT VERIFICATION WORK SHEET - FIELD DATA
City/Town; M/^M , /fj. By:
Location: T/iAffLa fa. ST»*J fcetr SV. •' W*vf«.y GW A. Date
Sketch of location and notes:
TRAPEiO
RD.
At
C-23
-------
HOT SPOT VERIFICATION WORK SHEET - UNINTERRUPTED FLOW
City/Town: W MT MA>\
Street/Highway Section:
pagej of [_
By: fr»HC-
Date: (c/n/7f
I. FASIC co: MUTATIONS:
Uw
JL. TOLl'.iS: Enter pea* hour voLunci for vlr.ccr
r>7?-13 (fm T'_t
ound t*nt 1
\o.
y
6GC
( 3CC
- ^ 7
l.t>
II. CORRECT FOR LAME EDGE TO RECEPTOR DISTANCES:
Assume receptor Is on
H
side of street
lt««
A. UN"; ETCE TO FiCEPTX)^ DISTANCE CORS-
ICTIOM fACTOF-5: Enter lane ed^c Co
for «sch lane CobtJir.eti frcn Flp. )
». ILKrTOR CC::CC,T2.\7;0:,5 ATTllLoIAS'-C
70 LAGi 1A.\;: tnt^r corrected co^cer.-
I-D tLnii II-A, ibcr/t
/
/ 5?
1 J *-
3 ^
tE.fH'i »
sound LJn<
So.
^5^V
bound Line
No.
/
1 (^
a o
\/
/\
4.J
Assume receptor is on
side of street
Uf»
C. IANT E1CJ TO ?£Cr?T"JR DISTANCE COR.1-
ICT10N rAC7?r3: Cr.tcr Unc tj(;c to
for cacS line (cbtJir.cc frca 7'.e. )
•n RTCSFTOR coxCi;rrJ.\T:c:;s xTTRiairD'-jLE
TO EACrt LAJ.I: Enter corrected concen-
tration!, cCKzjutc-i »• th* product of
1-C ind 1I-C, «bov«
jound L-Qno
So.
,'o.
V
/ \
III. FTKAL COMPUTATIONS OF M\Xl>rUM l-HR AND 8-HR AVERAGE CONCENTRATIONS
Jteo
A. rra:. eo'7i-\T:r:s cr I-H.I AVO S-KS AVEV.CE
a\\CG>-p.\i:cxS.- Enter c r* .'ollovlr.j; (1)
«r^ II-D. O.vO In coiur.n j; ID f^. (fro«
d.t. I'-rit.) U coU-n b; (3) b.cV^rcu^d
vl)f) [n cj'.^r. d; (t? 8-hr c. r re '. • 1 1 3n f»c-
coluro (. C u -.-, . u t • (mil con;crtr*Cioni • I
I ho\.T. In col i.i.:_r i t, «, jnd j, (or rectpcon
w Wth lUti of tireeC
Loct c ion
Citrr *c-
ildj)
BcO\
a
Coiputed
Receptor
Cone,
i
b
£va
1. C T,
C
Corrected
Cone.
(a X b)
G.\
^
*
I.eV.-
j round
Cone.
„. »
i-«o
.
Total
1-hr av« .
Cone.
-------
j]QT_SPOT VERIFICATION WORK SHEET - FIELD DATA
City /Town: _ WALTHAH, MA.
Location:
ST.
Sketch of location and notes:
.4
JT:
fAJif.o-' 6
By; TfiM
Date : 2t $tf 75
I,
C-25
-------
HOT SPOT VERIFICATION WORK SHEET - UNINTERRUPTED FLOW
City/Town:
By:
Street/Highway Section
I. BASIC COMPUTATIONS:
S,T
Date:
Itn
A. VOll'.iS: Lntrr f-cj'x l-.^ur volu^ci lor winter
1977-73 ((rr-i tl-x sHrctl)
1. UN!: CAPACITY: [mer line capictty (fron d«li
• herd)
C. V/C: Enc-r V/C for e«;h Une (A 4- B, «bo-va)
D. UN- CTSCC.S-^TUSS. tnctr Ur.t concent t« duo.
c^oputfd froo A Jr.ii C, ibjvc, a-id Fl$cr«
/
7-7C
1 30C
>M>
3-t
we^ t
bound Line
'o.
e.^^l-b
o-und Li nt !
'o.
J
77C
i ;JCC
.'»i
^.i
II. CORRECT FOR LANE EDGE TO RECEPTOR DISTANCES:
Assume receptor is on M 0 RT H
side of street
Itta
A. LAST C7CE TO rlCCPTOR DISTANCE COR?.-
FCTIOM FACTORS : Enter lane ed^c to
TO EACa LA.VI: Enter corrected conccr.-
trJtic.ni, c 0=7 ucci A* t-ho prcKlucc o£
I-D iftd H-A/tbcvB
1
/ 77
4.G
wesr
bound Lir.e
No.
£^T
bound Line
Mo.
/
/ . o •;
*.*
V
/ \
/ N
r,
Assume receptor is on
side of street
Itta
C. UNT HCE TO RICr?TO?, DISTANCE CC?_^-
ECTTON FA.CT\JKJ; tntor Kir.c cJcc to
•ix ncc^TeR co:,'CL:~r.\7iCNs ATT^ICIUIABL£
TO EACi IA:.L: C.-.:tr corrected cor.cen-
tr*tloni, coc^uccd 4fl th* product of
I-E *n?:Tuirvs cr I-H^ AST B-HS Avtwcc
a'SCCCFAKOSS: Cnt.r t !v foUovlrg; (1)
• nc1 11-D. Jbove) In colvirn *; (?) |^ (frca
C"*:* iStft») tn ccU-i b; (3) bac'-QrouTd
vli») In column d; (i) 5-hr eorrelitlon f.c-
lor (0.7 vrlfii oi^rrvlit ic:fr-.lr.cO In
Location
(itrct t-
fi^c)
kJ r, o r H
t
Computed
F^ c e p t o r
COQC.
. .i
V
f
1. t V»
e
Correct* d
Cone.
(• x b)
^ C
*
I.cV-
g round
Cone.
s" .c
.
Tot4l
1-hr «v«.
Cone.
(e + <1)
; 1 C
f
8-hr.
Corre Uc.
Factor
^ -,
*" '
t
Eit. S-Sr
Av*. Cone.
(. x 1)
CJ <
C-26
-------
TECHNICAL HCPORT DATA
reitJ lininicliniis on llic revfne ^c/(V^• r
I. RtPORT NO.
EPA-901/9-76-001
3. ULCiritNT'U ACCISSION-NO.
4. TITLE AND SUUTITLE
Guidelines for Identification and Evaluation of
Localized Violations of Carbon Monoxide Standards
fj. HEPOfIT DATE
January 1976
6. PERFORMING ORGANIZATION CODE
7. AUTHOniS)
Theodore P. Midurski, Alan H. Castaline
a. PERFORMING ORGANIZATION REPORT NO.
GCA-TR-75-35-G(l)
9. PERFORMING ORGANIZATION NAME AND ADDRESS
GCA CORPORATION
GCA/TECHNOLOGY DIVISION
Bedford, Massachusetts 01730
10. PROGRAM ELEMENT NO.
11. CONTRACT/GRANT NO.
68-02--1337 TO No. 6
12. SPONSORING AGENCY NAMF. AND ADDRESS
U.S. Environmental Protection Agency
Region I Office
Boston, Massachusetts 02203
13. TYPE OF REPORT AND PERIOD COVERED
Final Report
14. SPONSORING AGENCY CODE
15. SUPPLEMENTARY NOTES
16. ABSTRACT
This report presents guidelines for the identification and evaluation of localized
violations of carbon monoxide air quality standards in the vicinity of -streets and
highways. The guidelines are provided to facilitate the rapid and efficient review
of CO conditions along existing roadway networks, without the need for extensive
air quality monitoring, and are based upon the use of limited traffic -data. Two '
stages of review are provided for. Preliminary screening, performed with simple
nomographs included herein, simply identifies those locations with the potential to
violate CO standards; no quantitative estimate of CO concentrations results from
preliminary screening. Verification screening, using procedures and forms provided
herein, allows for consideration of- additional site-specific conditions and provides
quantitative estimates of maximum CO concentrations. Both screening procedures are
performed manually and are based upon the.EPA Indirect Source Review Guidelines.
Data collection pi'ocedures, computation techniques, and forms are recommended, and
examples are provided.
7.
KEY WORDS AND DOCUMENT ANALYSIS
DESCRIPTORS
b.lDENTIFIERS/OPEN ENDED TERMS C. COSATI Fidd/CfOUp
Air Pollution
Atmosphere Contamination Control
Atmospheric Models
Carbon Monoxide
Exhaust Gases
Traffic Engineering
Transportation/Urban Planning
Air Pollution Model
Automobile Exhaust
Highway Corridor Air
Quality Analyses
Relationships Between
Traffic and Nearby
Air Quality
13/13B
8. DISTRIBUTION STATEMENT
19. SECURITY CLASS (1 liis Krport)
UNCLASSIFIED
21. NO. OF PAGES
164
20. SECURITY CLASS (Thitpage)
UNCLASSIFIED
22.
EPA Form 2220-1 (9-73)
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