HomeMy WebLinkAbout1988-07-19; City Council; 9545; City of Carlsbad Traffic Signal EvaluationCI-’ OF CARLSBAD - AGEN[- BILL
CITY OF CARLSBAD TRAFFIC SIGNAL EVALUATION POLICY DEPT.ENG
Adopt Resol uti on No. approving implementation of the procedures contained in the City of Carlsbad Traffic Signal Evaluation Policy.
ff-J s’a,
ITEM EXPLANATION:
The Traffic Engineering Division of the Engineering Department has completed the attached Traffic Signal Evaluation Pol icy which also includes the Traffic Signal Qualification List. The City of Carlsbad has never had such a list that prioritizes warranted traffic signals for future installation. It is proposed that the list be evaluated periodically for the inclusion of additional, warranted signals or when re-prioritization of the list is necessary due to changing traffic conditions.
Ranking traffic signals on the basis of a rational, evaluation policy allows each location to be compared under similar criteria. This enables a list to be established based upon objective, traffic engineering procedures and data that indicates the relative magnitude of traffic conditions at a particular intersection compared with other intersections. Warranted traffic signals on the Qualification List can be installed in any order of need, based upon the circumstances applicable to each individual intersection. The Traffic Signal Evaluation Pol icy was recommended for implementation by the Traffic Safety Commission at the June 6, 1988 meeting by a 3-0 vote, with one (1) abstention.
FISCAL IMPACT:
No impact until the traffic signal is installed.
EXHI BITS :
1. Resolution No. ff-aSL approving implementation of the procedures contained in the City of Carlsbad Traffic Signal Evaluation Policy.
2. City of Carlsbad Traffic Signal Evaluation Policy.
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RESOLUTION NO. 88-252
A RESOLUTION OF THE CITY COUNCIL OF THE CITY OF CARLSBAD
CALIFORNIA, APPROVING IMPLEMENTATION OF THE TRAFFIC
SIGNAL EVALUATION POLICY.
WHEREAS, the City of Carlsbad recognizes the need for the installation of
traffic signals at various intersections to promote the safe and efficient
movement of people and goods; and
WHEREAS, the City of Carlsbad recognizes the need for an objective policy
to determine when and where traffic signals will be installed in the future; and
WHEREAS, establishing a qualification list of warranted traffic signals
will be used for future Capital Improvement Programs (C.I.P.) or developer
projects to determine the need and schedule of the installation;
NOW, THEREFORE, BE IT RESOLVED by the City Council of the City Carlsbad,
California, as follows:
1. That the above recitations are true and correct.
2. The City Council of the City of Carlsbad adopts the procedures
contained in the entitled "Traffic Signal Evaluation Policy."
3. The Engineering Department of the City of Carlsbad is hereby
authorized to periodically update the Traffic Signal Qualification List contained
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in the Traffic Signal Evaluation Policy and present such updated list to the
Traffic Safety Commission and City Council for review and approval.
PASSED, APPROVED AND ADOPTED at a regular meeting of the Carlsbad City
Council held on the 19th day of July 1988 by the
following vote, to wit:
AYES: Council Members
NOES: None
ABSENT: None
ATTEST: & A?& ALEJHA L. RAUTENKRANZ, City C1;dr-k (SEAL)
Lewis, Kulchin, Pettine, Mamaux and Larson
-.- I
I *TRAFFIC _- SIGNAL EVALUATION
POLICY
PREPARED BY:
ENGINEERING DEPARTMENT
TRAFFIC ENGINEERING DIVISION
JUNE 1988
CITY OF CARLSBAD
Traffic Engineering Division
Traffic Signal Evaluation Policy Report
June 1988
Table of Contents
Page No.
Introduction .................... 1
Background and Purpose ............... 1
Policy.. ..................... 2
General ...................... 3
Data....... ................. 4
Traffic Signal Qualification List ......... 7
Traffic Signal Design List ............. 8
Unwarranted Traffic Signal Location List
Atmendix
A. Traffic Signal Qualification Rating System
8
B. CALTRANS Traffic Signal Warrants
CITY OF CARLSBAD Traffic Engineering Division TRAFFIC SIGNAL EVALUATION POLICY REPORT
INTRODUCTION
The City of Carlsbad, located in North San Diego County, has in recent
years grown from a small, agricultural based residential community to
a moderate size city of approximately 60,000 with various industrial,
commercial, recreational, residential and agricultural land uses. As-
sociated with this growth has been a substantial increase in vehicular,
bicycle, and pedestrian traffic.
With increased volumes on Carlsbad's roadway system, it is apparent
that there is need for a more detailed method of evaluating and
determining future traffic signal locations. At this time, there are
42 signalized intersections in Carlsbad that are maintained by City
forces .
The following report is based on this need to identify and qualify the
future installation of traffic signals at various locations throughout
the City of Carlsbad. It is the basis for a system that will
continually be re-evaluated and updated on a regular basis.
The Traffic Signal Qualification List is not steadfast. Financial con-
straints, private development, capital improvement projects or other
valid considerations may dictate that a lower qualifying signal be
installed at a given location. The qualification list does, however,
serve as a guide for future traffic signal installations and only
includes locations meeting CALTRANS signal warrants.
BACKGROUND AND PURPOSE
As traffic volumes increase there becomes a need to consider various
right-of-way controls at intersections. Depending upon traffic charac-
teristics at a given intersection, the City will evaluate and choose
from a variety of traffic control methods or devices to facilitate the
safe and efficient movement of traffic.
1
Included among the various traffic control devices are: basic rules
of the road governing right-of-way at intersections, yield sign instal-
lations, 2-way STOP sign installations, 3-way and 4-way STOP sign in-
stallations, channelization and median control and traffic signals.
This report focuses on creating a Citywide listing of one of the safest
and most efficient methods of intersection right-of-way control, the
traffic signal. The purpose of a traffic signal qualification list is
to compare and impartially rank the intersections under consideration.
A Traffic Signal Qualification List has never been established for the
City of Carlsbad. All locations to be included on the list must meet
California Department of Transportation criteria (CALTRANS Signal War-
rants) for the installation of a traffic signal.
POLICY
As with most traffic engineering departments, it has been the policy
of the City of Carlsbad Traffic Engineering Division to only recommend
installation of traffic signals that meet the minimum criteria
established by the California Department of Transportation. All data
collection and evaluation to determine if criteria is met for a loca-
tion to qualify for a traffic signal is under the direction of the City
Engineer.
2
GENERAL :
Traffic signals are electrically powered traffic control devices that
direct the movement of vehicles, bicycles, and pedestrians at an inter-
section. Traffic signals provide for the positive assignment of the
right-of-way to effect the orderly movement of traffic with minimum
delay and maximum safety, usually more economically than by manual
methods.
Many cities use a priority list system for ranking traffic signal
projects. To qualify for this list, the signal analysis takes into
account the relative delays on approaching streets, the accident
history of the intersection and gaps in the major and minor street
streams of traffic, pedestrian volumes and various other factors. An
evaluation is then conducted to determine if a signal will help
correct an identified problem.
Establishing a Traffic Signal Qualification List helps answer two basic
questions:
(1) Do traffic conditions at the intersection meet the basic
criteria that affect the benefits and cost of signal con-
trol: and
if so, how does this location compare with other locations
throughout the City of Carlsbad that meet the same basic
criteria?
(2)
This evaluation provides a rational method of comparing one
intersection with another, the end result being a ranking that lists
the greatest need for signalization between all potential signal locat-
ions. The attached Traffic Signal Qualification List indicates each
location under consideration and is arranged in descending order based
upon the total qualification points accumulated at each location.
A listing of signals does not mean that signals will exclusively be
installed in the order of ranking. Existing conditions, right-of-way
needs, need for turn pockets, monetary constraints, or other factors
may reveal a signalization project that is more appropriate than those
higher on the list. The list establishes projects for which preli-
3
minary engineering
proceeding to final
should take place and then be evaluated before
design. Traffic signals are not installed unless
written authorization from the City Engineer directs their instal-
lation.
DATA:
In recent years traffic signals have experienced a technical evolution.
Changes have evolved from pre-timed signals in which control mechanisms
operate on a predetermined time schedule allotting a fixed amount of
time of each interval in the cycle: to traffic actuated microprocessor
units that can operate two to eight signal phases, highway ramp
metering control, master controls for interconnected signal systems
and traffic volume monitoring stations.
Traffic signals are an expensive control device to install and under
certain conditions more problems may be created than are solved. These
problems can range from increased accident frequency , delays, increased
air or noise pollution and higher energy use, to circuitous travel
along less desirable routes to avoid the signalized intersection.
A properly signalized intersection, however, can resolve many problems
and provide advantages ranging from reducing certain types of accident
frequency, delay, and air pollutants, to creating an orderly traffic
movement. In a coordinated signal system they help maintain an effi-
cient, progressive traffic movement along an arterial roadway.
Rankings of the various intersections for potential traffic signal
installation was accomplished by using a Traffic Signal Qualification
Rating System. Points were assigned to seven Qualification factors
which are based on the California Department of Transportation criteria
known as CALTRANS Traffic Signal Warrants.
Traffic Signal Qualification Rating System factors include the follow-
ing:
Factor 1- Minimum Vehicular Volume
This factor considers the fact that at certain traffic volume levels
4
the delay can be reduced and orderly flow through an intersection
enhanced by signal controls.
Factor 2 - InterruDtion of Continuous Traffic
The interruption factor applies when the traffic volume on the major
street is so high that few gaps occur to permit the minor street
traffic to cross or enter the intersection. As a result, the minor
street traffic may suffer long delays or experience hazards at the
intersection.
Factor 3 - Minimum Pedestrian Volume
The minimum pedestrian volume factor reflects the length and fre-
quency of gaps available for pedestrians to cross the major street
as compared to the number of pedestrians that cross the street.
Factor 4 - School Area Traffic Sianals
This factor recognizes the special.problems that may occur at inter-
sections near schools or on school walking routes. It is similar to
the minimum pedestrian volume factor in that gaps in traffic are
considered.
Factor 5 - Proaressive Movement or Sianal Systems
Existing or proposed signal systems are considered by this factor.
Often traffic flow efficiency can be enhanced if signals are instal-
led at proper spacing along an arterial or signal network. Such
signals may assist in holding traffic in compact platoons that will
arrive at adjacent signalized locations in accordance with a turning
plan.
Factor 6 - Accident Historv
This factor reflects the fact the certain types of accidents could
be reduced by traffic signal control. However, experience has shown
that few changes in accident frequency can be expected at a location
that historically has less than five accidents per year, or an acci-
dent rate of less than about 1.0 accident per million vehicles.
5
This factor recognizes the special problems that may occur due to
the location of certain traffic generators, certain geometric or
roadway features, sight distance obstructions, and various other
criteria.
A summary of the factors considered to be special conditions and the
points that were assigned follows:
1. Four-way STOP Control (5 points): Typically, right-angle acci- dent frequency drops sharply after installation of a Four-Way STOP. However, total delay, as well as rear-end collision fre- quency, increase to a level higher than that which would be
reflected by the results of Factors $1 and #2.
2. Proximity of a school (1 to 5 points): Depending on the type
of school and its distance from the intersection in question,
points are assigned to reflect the potential benefit to school-
age pedestrians and bicycle traffic.
3. Horizontal and Vertical Curvature and Visibility (1 to 5 points): The alignment of a major street can affect the visi- bility available to side-street motorists, and the relative safety of their crossing or merging maneuvers. There may also be other restrictions to visibility, such as utility poles and appurtenances and trees and shrubs on private property.
4. High Speed on a Through Street (1 to 3 points) : In addition to
worsening the problems caused by visibility restrictions, very
high approach speeds can worsen the severity of the accidents
which occur.
The above rating system is used to evaluate various potential signal
locations; these locations are then ranked based on the following rela-
tive weight system:
Maximum
Factor DescriDtion
1 Minimum Vehicular Volume
2 Interruption
3 Pedestrian Volume
4 School Area
5 Signal System
6 Accident History
7 Special Conditions
Total Possible
pualification Points
15
10
10
10
5
15
- 15
80 Points
Relative
Weiqht
19%
12 %
12%
12%
7%
19%
- 19%
100%
6
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9.
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11.
1.
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11.
TRAFFIC SIGNALS CURRENTLY BEING DESIGNED
El Camino Real/Arenal Road
Melrose Drive/Rancho Santa Fe Road
Elm Avenue/Highland Drive
Elm Avenue/Jefferson Street
Elm Avenue/Roosevelt Street
Tamarack Avenue/Adams Street
Carlsbad Boulevard/Cannon Road
Roosevelt Street/Grand Avenue
Jefferson Street/Grand Avenue
I-S/Tamarack Avenue Ramps
College Boulevard/Palomar Airport Road
TRAFFIC SIGNAL LOCATIONS INVESTIGATED
1Did not meet CALTRANS Sianal Warrants)
La Costa Avenue/Cadencia Street
Palomar Airport Road/Palomar Oaks Way
Tamarack Avenue/Elm Avenue
Elm Avenue/Donna Drive
Camino Vida Roble/Yarrow Drive
Carlsbad Boulevard/Chestnut Avenue
Poinsettia Lane/Paseo Del Norte
La Costa Avenue/Romeria Street
Cannon Road/Avenida Encinas
Paseo Del Norte/Camino Del Las Ondas
Poinsettia Lane/Batiquitos Drive
Q
APPENDIX
TRAFFIC SIGNAL QUALIFICATION RATIN G SYSTEM
Factor 1 - tal Vehic ular volume
Points are assigned based upon the graph below which considers
major and minor street volumes and capacity. The entering volumes
are based upon 4-hour counts (usually from 2:OO to 6:OO P.M. on a
weekday). A maximum of 15 points may be assigned to this factor.
NOTES
1. ALL VOLUMES ARE FOR 4 HOURS (USUALLY 2-6 PA.)
2. MAXIM POINTS = 15
?SO
INTERSECTION _. .
2-2 LANE STS. 1500 la00 2000 2200 2400 2600 2800 3000 3200 3400 3600 3800 &OVER
1-2 8 1-4 LANE ST. 2200 2400 2600 2900 3000 3200 3400 3600 3800 4000 4200 4406 bVER
2-4 LANE STS. 2600 2800 3000 3200 3400 3600 3800 4000 4200 4400 4600 4800 BOVER
2-ONEUAY STS. 1080) 3200 3400 3600 3800 4000 4200 4400 4600 4800 5000 5200 5400 BOVER
TOTAL VOLUME ENTERING INTERSECTION
'FACTOR 2 - InterruDtion of Continuous Traffic
Vehicles on Through streets, if uncontrolled, tend to travel
through mindr street intersections at speeds that make it difficult
and hazardous for vehicles and pedestrians from the side street to
cross or enter the principal traffic stream. The total of the
minor street vehicles plus pedestrians crossing or entering the
major street must exceed 300 in four hours to receive any points.
A maximum of 10 points may be assigned to this factor.
4-Hour Major Street Volumes
0-1649
1650-1949
1950-2249
2250-2549
2550-2849
2850-3149
3 150-3449
3450-3749
3750-4049
4050-4349
Points
0
1
2
3
4
5
6
7
8
9
ADDrox. ADT
4 , 700
5,600
6,400
7,300
8 , 200
9 , 000
10 ,000
10,700
11,600
12,400
4350-over 10 12,500 and up
*’ Factor 3 - Pedestrian Volume
A traffic signal may be needed where many pedestrians cross
A maximum of 10 points may be assigned to this a major street.
factor.
NOTES
1. ALL VOLUMES ARE FOR 4-HOURS (USUALLY 2-6 P.N.) 2. MAXIMUM POINTS = 10
3. NO POINTS IF LESS THAN 100 PEDESTRIANS DURING THE 4 HOUR PERIOO. 4. NO POINTS IF LESS THAN 1200 MAJOR STREET VEHICLES DURING THE 4 HOUR PER100.
3600
OVER
3200
2800
2400
2000
1600
1200
100 200 400 600 800 1000 1200 1400 15006r
OVER
PEDESTRIANS CROSSING MAJOR STREET
-
' Factor 4 - School Area Traffic Sianals
Points are assigned based upon the number of school age
pedestrians crossing the major street as compared to the major
street traffic. This factor will apply only to locations within
one mile of a school and where the nearest controlled intersection
or potential crossing point is more than 600 feet away. A maximum
of 10
1500
1100
750
500
h - fu L 3 ai
W
250
NOTE :
points
1800
1400
1000
600 - c a
L =>
n
v
200
may be assigned for this factor.
100 150 200 250 350 (Urban)
60 100 140 180 220 (Rural)
PEDESTRIANS CROSSING THE MAJOR STREET (Per 2-Hour Period)
No points will be assigned if nearest controlled crossing is less than 600 feet away.
Factor 5 - Proaressive Movement or Siunal Svstems
This factor depends upon engineering studies and must include
the present and future traffic demands of the area. A signal may
be justified when it forms a part of an interconnected or
coordinated system. A maximum of 5 points may be assigned to this
factor.
Factor 6 - Accident Historv
Only those accidents susceptible to correction by traffic
signals are considered and then only if less restrictive measures
such as warning signs, proper lighting, painted markings, etc. have
failed. A maximum of 15 points may be assigned to this factor.
Accidents Points
0-2
3
4
5
6
7
9
10
11
12
13
14
a
15-over
0
1
3
5
6
7
8
9
10
11
12
13
14
15
NOTE t Use the average of the last two
years, provided the intersection has been in operation for two years.
Factor 7 - Sgecial Conditions
This factor considers extenuating circumstances that are not
covered in the previous six factors. These may include: the
proximity of schools, churches, public buildings, and other
traffic and pedestrian generators; an abrupt change from a rural
to an urban area; the need for police control during portions of
the day; a steep hill; a horizontal curve; restricted sight
distance. This factor requires engineering judgment based on
physical inspection of the site. A maximum of 15 points may be
assigned to this factor.
Traffic Manual TRAFFIC SIGNALS AND LIGHTING 9-1
12-19a
-
CHAPTER 9
TRAFFIC SIGNALS AND LIGHTING
SECTION 9-00 TRAFFIC SIGNALS, BASIC INFORMATION AND WARRANTS
901.1 Introduction
A traffic signal is an electrically powered traffic control device, other than a barricade warning light or steady burning electric lamp, by which traffic is warned or directed to take some specific action. The following types and uses of traffic signals are discussed in this chapter: Traffic Control Signals, Pe- destrian Crossing Signals, Ramp Metering Signals, Flashing Beacons, Lane-use Control Signals, Traffic Control at Movable Bridges, Priority Control of Traf-
fic Signals, Traffic Signals for One-lane, Two-way Facilities and Traffic Signals for Construction Zones.
Traffic control signals are valuable devices for the control of vehicle and pedestrian traffic. However, because they assign the right of way to the various traffic movements, traffic control signals exert a pro- found influence on traffic flow. Traffic control signals, properly located and oper- ated, usually have one or more of the foilowing ad- vaxitages:
1.
2.
3.
4.
5.
They provide for the orderly movement of traf-
fic.
Where proper physical layouts and control measures are used, they increase the traffic-
handling capacity of the intersection.
They reduce the frequency of certain types of accidents, especially the right-angle type.
Under favorable conditions, they can be coor- dinated to provide for continuous or nearly con- tinuous movement of traffic at a definite speed
along a given route.
They permit minor street traffic, vehicular or pedestrian, to enter or cross continuous traffic on the major street.
Improper or unwarranted signal installations may
1. Excessive delay.
2. Disobedience of the signal indications.
3. Circuitous travel of alternate routes.
4. Increased accident frequency.
Experience shows that the number of right-angle collisions may decrease after the installation of sig- nals, but the number of rear-end collisions may in- crease. The installation of signals may increase over- all delay and reduce intersection capacity.
cause:
Consequently, it is of the utmost importance that the
consideration of a signal installation and the selection
of equipment be preceded by a thorough study of traffk and roadway conditions made by an engineer experienced and trained in this field. Equally impor- tant is the need for checking the efficiency of a traffic signal in operation. This determines the degree to which the type of installation and the timing pro-
gram meet the requirements of traffic.
942.0 traffic Signal Warrants
The justification for the installation of a traffic sig- nal at an intersection is based on the warrants stated
in this Manual and in the Manual on Uniform Traffic
Control Devices. The decision to install a signal should not be based solely upon the warrants, since the installation of traffic signals may increase certain types of collisions. Delay, congestion, approach con- ditions, driver confusion, future land use or other evidence of the need for right of way assignment beyond that which could be provided by stop signs must be shown. See Section 4-03.3 for stop sign war- rants. When the 85th-percentile speed of traffic on the major street exceeds 40 miles per hour in either an urban or rural area, or when the intersection lies
within the built-up area of an isolated community
having a population of less than lO,OOO, the location
is considered rural. All other areas are considered
urban. Figures 9-1A, 9-1B, 9-1C and 9-1D are examples of warrant sheets. Warrant sheet 9-1C should be used only for new intersections or other locations where actual traffic volumes cannot be counted. The installation of a traffic signal should be consid- ered if one or more of the warrants listed below are met:
942.1 Warrant 1 - Minimum Vehicular Volumo
The Minimum Vehicular Volume warrant is in- tended for application where the volume of inter- secting traffic is the principal reason for considera- tion of a signal installation. The warrant is satisfied when for each of any 8 hours of an average day the traffic volumes given in the table below exist on the major street and on the higher-volume minor street approach to the intersection.
9-2 TRAFFIC SIGNALS AND LIGHTING Traffic Manual
12.1-
Sittnkr or Vrhich prr \ c-hiclc\ pcr latics for hour 011 hour oti mO\-illp major strmt highrr-\ olitinr trumc 011 (t0t.d of tniiior-rtrcct roch ;ippro;lch Imth .ipproach (OIIC iipprouchrs) dirrction
<)Ill?. I
.Muor Street .Minor Street Lrrhrn Rurd ilr6.111 firrid I ........................ 1 .......................... 500 m 1% 109 2 or more ........ I .......................... 600 420 1% IOS 2 or more ........ 2 or more ........ 600 420 200 IM 1 ........................ 2 or more ........ 500 390 200 110
The major street and the minor street volumes are for the same 8 hours. During those 8 hours the direc- tion of higher volume on the minor street may be on
one approach during some hours and on the opposite approach during other hours. Left turn movements from the major street may be included with minor street volumes if a separate
signal phase is to be provided for the left turn move-
ment. The left turn volume in the highest direction
may be added to the minor street volume on the highest approach. The major street volume should be reduced by this .amount. The major street and the minor street volumes are for the same 8 hours. During those 8 hours the direc- tion of higher volume on the minor street may be on one approach during some hours and on the opposite approach during other hours. Left turn movements from the major street may be included with minor street volumes if a separate signal phase is to be provided for the left turn move-
ment. The left turn volume in the highest direction
may be added to the minor street volume on the
highest approach. The major street volume should be
reduced by this amount.
942.2 Warrant 2 - Intorruption of Continuous Traffic
The Interruption of Continuous Traffic warrant applies to operating conditions where the traffic vol- ume on a major street is so heavy that traffic on a minor intersecting street suffers excessive delay or hazard in entering or crossing the major street. The warrant is satisfied when, for each of any 8 hours of an average day, the traffic volumes given in the table below exist on the major street and on the higher- volume minor street approach to the intersection, and the signal installation will not seriously disrupt progressive traffic flow.
942.3 Warrant 3 - Minimum Podortrian Volumo
The Minimum Pedestrian Volume warrant is satis-
fied when for each of any 8 hours of an average day the following traffic volumes exist:
I. .......
1.
2.
\ rhiclr\ pr l.inr\ [or hour uti hour 011 ino\ itig iiiilior rtrret htgher.\olutnc triific 011 ( totiti or tniiior+trcrt wch .ippro.ich both .kpproiich (ow dirrctioti .ippro;icho) only I
Ktttnhr of t'rhicln pr
.ilajor Street .Minor Street Urban Rim/ L'rbiila Ror;rl I I 790 525 73 53 2 or more ........ 1 ........................ 900 630 75 33 2 or more ........ 2 or more ...... 900 630 LOO in
.......................... ........................
.- ................ ........ io0 70 2 or more 750 525
On the major street 600-Urban, 420-Rural or more vehicles per hour enter the intersection (total of both approaches) : or 1,000-Urban, 700- Rural or more vehicles per hour (total of both approaches) enter the intersection on the ma- jor street where there is a raised median island
four feet or more in width; and
During the same 8 hours as in paragraph l., there are 150-Urban, 105-Rural or more pede- strians per hour on the highest volume cross- walk crossing the major street.
A signal installed under this warrant at an isolated intersection should be of the traffic-actuated type with push buttons for pedestrians crossing the major street. If such a signal is installed at an intersection
within a signal system, it should be equipped and
operated to provide proper coordination. Signals may be installed at nonintersection ha-
tions (Mid-block) , provided the requirements of this
warrant are met, and provided that the related cross- walk is not closer than 150 feet to another established crosswalk. Curbside parking should be prohibited for
a minimum of 100 feet in advance of and 20 feet beyond the crosswalk. Phasing, coordination and in- stallation must conform to standards set forth in this Manual. Special attention should be given to the sig nal head placement and the signs and markings used at nonintersection locations to be sure drivers are aware of this special application.
942.4 Warrant 4 - School Aroar
See Chapter 10.
9-02.5 Warrant 5 - Progrerrivo Movoment
when: The Progressive Movement warrant is satisfied
On a one-way street or on a street which has predominantly unidirectional traffic, adjacent
signals are so far apart that the necessary degree of platooning and speed control of vehicles would otherwise be lost or,
On a two-way street, where adjacent signals do not provide the necessary degree of platooning and speed control and the proposed and adja- cent signals could constitute a progressive signal system.
. Traffic Manual TRAFFIC SIGNALS AND LIGHTING 9-3
12-1988
The installation of a signal according to this war- rant should be based on the &-percentile speed un- less an engineering study indicates that another speed is more desirable. The installation of a signal according to this war- rant should not be considered where the resultant signal spacing would be less than 1,OOO feet.
902.6
when:
Warrant 6 - Accidont Exporionce
The Accident Experience warrant is satisfied
1.
2.
3.
4.
Five or more reported accidents of types sus- ceptible to correction by traffic signal control have occurred within a 12-month period, each accident involving personal injury or property damage to an apparent extent of $200 or more; and
Adequate trial of less restrictive remedies with satisfactory observance and enforcement has failed to reduce the accident frequency; and
There exists a volume of vehicular and pedes- trian traffic not less than 80 percent of the re- quirements specified in the minimum vehicular volume warrant, the interruption of continuous
traffk warrant, or the minimum pedestrian vol-
ume warrant; and
The signal installation will not seriously disrupt
progressive traffic flow.
942.7 Warrant 7 - Syrtomr Warrant
A traffic signal installation at some intersections may be warranted to encourage concentration and organization of traffic flow networks. The systems warrant is applicable when the common intersection of two or more major routes has a total existing, or immediately projected, entering volume of at least
800 vehicles during the peak hour of a typical week-
day, or each of any five hours of a Saturday and/or Sunday. A major route as used in the above warrant has one or more of the following characteristics:
1. It is part of the street or highway system that serves as the principal network for through traf-
fic flow;
2. It connects areas of principal traffic generation;
3. It includes rural or suburban highways outside of, entering or traversing a city;
4. It has surface street freeway or expressway ramp terminals;
5. It appears as a major route on an official plan such as a major street plan in an urban area traffic and transportation study.
942.8 Warrant 8 - Combinotion of Warrants
In exceptional cases, signals may be justified where no single warrant is satisfied but where any two of Warrants 1, 2 and 3 are satisfied to the extent of 80 percent or more of the stated numerical values.
942.9 Warrant 9 - Four Hour Volumo Wanant
The Four Hour Volume Warrant is satisfied, when for each of any four hours of an average day, the plotted points representing the vehicles per hour on the major street (total of both approaches) and the corresponding vehicles per hour on the higher vol- ume minor street approach (one direction only) all
fall above the curve in Figure 9-2A for the existing combination of approach lanes. When the 85th percentile speed of the major street
traffic exceeds 40 miles per hour, or when the inter- section lies within a built-up area of an isolated com- munity having a population of less than lO,O00, the four hour volume requirement is satisfied when the plotted points referred to fall above the curve in Figure 9-2B for the existing combination of approach lanes.
942.10 Warrant 10 - Peak Hour Doloy Warrant
: The Peak Hour Delay Warrant is intended for ap
plication where traffic conditions are such that for one hour of the day, minor street traffic suffers un-
due delay in entering or crossing the major street.
The peak hour delay warrant is satisfied when the conditions given below exist for one hour (any four
consecutive 15-minute periods) of an average week-
day. The peak hour delay warrant is met when:
1. The total delay experienced by traffic, on one minor street approach controlled by a STOP sign, equals or exceeds four vehicle-hours for a one-lane approach and five vehicle-hours for a two-lane approach, and
2. The volume on the same minor street approach equals or exceeds 100 vph for one moving lane of traffic or 150 vph for two moving lanes, and
3. The total entering volume serviced during the hour equals or exceeds 800 vph for intersections with four or more approaches or 650 vph for intersections with three approaches.
Warront 11 - Peak Hour Volumo Warrant 942.11
The Peak Hour Volume Warrant is intended for application where traffic conditions are such that for one hour of the day minor street traffic suffers undue delay in entering or crossing the major street. The peak hour volume warrant is satisfied when the plotted point, representing the vehicles per hour on the major street (total of both approaches) and the corresponding vehicles per hour on the higher
Traffic Manual .94 TRAFFIC SIGNALS AND LIGHTING
lblsm
volume minor street approach (one direction only) for one hour (any four Consecutive 15-minute pi- ods) of an average day, falls above the curve in Fig ure 9-2C for the existing combination of approach lanes. When the 85th percentile speed of major street traffic exceeds 40 miles per hour, or when the inter- section lies within a built-up area of a isolated com- munity having a population of less than lO,oOO, the
peak hour volume warrant is satisfied when the plot- ted point, referred to above, falls above the curve in Figure 9-2D for the existing combination of approach
lanes.
94.0 Ouidolinos for Lofi Turn Pharos
Since separate signal phases for protected left turns will reduce the green time available for other phases, alternate means of handling left turn con- flicts should be considered first. The most likely possibilities are:
1. Prohibition of left turns. This can be done only if there are convenient alternate means of mak- ing the movement. Typical alternate means are: (a) a series of right andlor left turns around a
block to permit getting to the desired destina- tion, or (b) making the left turn at an adjacent unsignalized intersection during gaps in the op- posing through traffic.
2. Geometric changes to eliminate the left turn.
An effective change would be a complete sepa- ration or a compiete or partial “clover leaf’ at grade. Any of these, while eliminating left turns, requires additional cost and right of way.
Protected left turn phases should be considered where such alternatives cannot be utilized, and one
or more of the following conditions exist:
1. Accidents. Five or more left turn accidents for a particular left turn movement during a recent
12-month period.
2. Delay. Left-turn delay of one or more vehicles ’
which were waiting at the beginning of the green interval and are still remaining in the left turn lane after each cycle for one hour.
3. Volume. At new intersections where only. es- timated volumes are available, the following cri- teria may be used. For a pretimed signal or a
background-cycle-controlled actuated signal, a
left turn volume of more than two vehicles per
approach per cycle for a peak hour; or for a traffic-actuated signal, 50 or more left turning vehicles per hour in one direction with the product of the turning and conflicting through traffic during the peak hour of 100,OOO or more.
4. Miscellaneous. Other factors that might be con-
sidered are: consistency of signal phasing with that at adjacent intersections, impaired sight distance due to horizontal or vertical curvature,
or where there is a large percentage of buses and trucks.
.,
904.0 Romoval of Existing Signals
Changes in traffic patterns may result in a situation where a traffic signal is no longer justified. When this occurs, consideration should be given to removing
the traffic signal and replacing it with appropriate
alternative traffic control devices.
Traffic Manual TRAFFIC SIGNALS AND LIGHTING 9-5
12.1908
Flgun 9-1 A
TRAFFIC SIGNAL WARRANTS
1
ACH .s
CALC DATE
CHK DATE
MINIMUM REQUIREMENTS
(8- SHOWN IN BRACKETS)
UR UR
1 2 or more ///////
---- DlST CO RTE PM
BothApprcha 500 350 MajorStrsst (400) (280)
Highset ADDrchl 150 105
Major St: Critical Approach Speed mPh
Minor St: Critical Approach Speed mPh
cl --------- 0 OR RURAL(R)
0 URBAN(U)
Critlcal speed of major street traffic,) 40 mph -------------------
In built up area of isolated community of < 10,000 pop. -
600 420
(480) (338)
200 140
WARRANT 1 - Minimum Vehicular Volume 100% SATISFIED YES 0 NO 0
80% SATISFIED YES 0 NO 0
MIN. REQUIREMENT DISTANCE TO NEAREST ESTABLISHED CRWLK.
150 Feet N/E-ft SMI-ft
FULFILLED
Yes 0 NO 0
I APPRO Hour
* NOTE: Heavier left turn movement from Major Street included when LT-phasing is proposed 0
WARRANT 2 - Interruption of Continuour Traffic 100% SATISFIED YES 0 NO 0
80% SATISFIED YES 0 NO 0
Hour
*NOTE: Heavier left turn movement from Major Street included when LT-phasing is proposed
WARRANT 3 - Minimum Pedortrian Volume 100% SATISFIED YES 0 NO 0
80% SATISFIED YES 0 NO 0
SHOWN IN BRACKETS)
Hour
The satisfaction of a warrant is not necessarily justification for a signal. Delay, congestlon, confusion or other evidence of the need for right of way assignment must be shown.
'94 TRAFFIC SIGNALS AND LIGHTING Traffic Manual
12-1slr
MINIMUM REQUIREMENTS
>1000ft
F lgum 0-1 B
TRAFFIC SIGNAL WARRANTS
DISTANCE TO NEAREST SIGNAL FULFILLED
YESO NO N 3s fi, E fi, W n
WARRANT 4 - School Crossings Not Applicable 0
See School Crossings Warrant Sheet 0
ON ONE WAY ISOLATED ST. OR ST. WITH ONE WAY TRAFFIC SIGNIFICANCE AND ADJACENT SIGNALS
ARE SO FAR APARTTHAT NECESSARY PLATOONING 6 SPEED CONTROL WOULD BE LOST ----------- _---_-__---___I-------------------------.
ON 2-WAY ST. WHERE ADJACENT SIGNALS DO NOT PROVIDE NECESSARY PLATOONING 6
SPEED CONTROL PROPOSED SIGNALS COULD CONSTITUTE A PROGRESSIVE SIGNAL SYSTEM 00
WARRANT 6 - Accident Experience SATISFIED YES 0 NO 0
MINIMUM REQUIREMENT
5 OR MORE.
REQUIREMENT 1 WARRANT I dl FULFILLED
ONE WARRANT I WARRANT 1 - MINIMUM VEHICULAR VOLUME I
NUMBER OF ACCIDENTS I a0
I
MINIMUM VOLUME REQUIREMENT ENTERING VOLUMES - ALL APPROACHES
DURING TYPICAL WEEKDAY PEAK HOUR VEHlHR ------------------------------------------------.-. 800 VEH/HA
DURING EACH OF ANY 5 HRS OF A SATURDAY AND/OR SUNDAY
VEHlHR
OR 80% WARRANT 3 - MINIMUM PEDESTRIAN VOLUME
FULFILLED v,
YES NO 0
I SIGNAL WILL NOT SERIOUSLY DISRUPT PROGRESSIVE TRAFFIC FLOW I
CHARACTERISTICS OF MAJOR ROUTES MAJOR ST MINOR ST
HWY SYSTEM SERVING AS PRINCIPLE NETWORK FOR THROUGH TRAFFIC
CONNECTS AREAS OF PRINCIPLE TRAFFIC GENERATION
RURAL OR SUBURBAN HWY OUTSIDE OF, ENTERING, OR TRAVERSING A CITY
HAS SURFACE STREET WY OR EXPWAY RAMP TERMINALS
APPEARS AS MAJOR ROUTE ON AN OFFICIAL PLAN
.---____________-_---------------------------------
.---__--_____-I-__-_------------------------.------
.--_-__-__-_______L____________________I----------- .--_________--______-------------------------------
a0 ADEQUATE TRIAL OF LESS RESTRICTIVE REMEDIES HAS FAILED TO REDUCE ACC. FREQ.
WARRANT 7 Systems Warrant SATISFIED YES 0 NO 0
The satisfaction of a warrant is not necessarily justification for a signal. Delay, congestion, confusion or other evidence of the need for right of way assignment must be shown.
Ts-108
' Traffic Manual TRAFFIC SIGNALS AND LIGHTING 9-7
12.1-
REQUIREMENT WARRANT
TWO WARRANTS
SATISFIED
1 - MINIMUM VEHICULAR VOLUME
2 - INTERRUPTION OF CONTINUOUS TRAFFIC
80% 3 - MINIMUM PEDESTRIAN VOLUME
Figun 0.1 C
TRAFFIC SIGNAL WARRANTS
d FULFILLED
YES 0 NO 0
WARRANT 8 - Combinatlon of Warrants SATISFIED YES 0 NO 0
WARRANT 9 - Four Hour Volume SATISFIED+ YES 0 NO 0
2 or Approach Lanes One more Hour
Both Approrches , M8jor Street
Highest Approaches , Minor Street
*Refer to Fig. 9-2A (URBAN AREAS) or Figure 9-28 (RURAL AREAS) to determine if this warrant is satisfied
WARRANT 10 - Peak Hour Delay SATISFIED YES 0 NO 0
1. The total delay experienced for traffic on one minor street approach controlled by a STOP sign equals or exceeds four vehiclehours for a onelane approach and five vehiclehours for a two-lane approach; and
YES 0 NO 0
2. The volume on the same minor street approach equals or exceeds 100 vph for one moving lane of traffic or 150 vph for two moving lanes; and
YES 0 NO 0
3. The total entering volume serviced during the hour equals or exceeds 800 vph for
intersections with four or more approaches or 650 vph for intersections with three approaches.
YES 0 NO 0
WARRANT 11 - Peak Hour Volume SATISFIED' YES 0 NO 0
2 or
Approach Lanes One more Hour
Both Amroachr , M40r Street
High-t Approach- , Minor Stroot
*Refer to Fig. 9-2C (URBAN AREAS) or Figure 9-20 (RURAL AREAS) to determine if this warrant is satisfied.
The satisfaction of a warrant is not necessarily justification for a signal. Delay, congestion, confusion or other evidence of the need for right of way assignment must be shown.
TS-roc
w TRAFFIC SIGNALS AND LIGHTING Traffic Manual 12-1#1
FIQu~ 0-1 D
TRAFFIC SIGNAL WARRANTS
Vehicles per day on major
street (total of both
approaches)
Urban Rural
8,000 5,600
9,600 6,720
9,600 6.720
8.000 5.600
V.ehicles per day on major
street (total of both
approaches)
(Based On Estimated Average Daily Traffic - See Note 2)
Vehicles per day on higher-
volume minor-street approach (one direction only)
Urban Rural
2,400 1,680
2,400 1,680
3,200 2.240
3,200 2,240
Vehicles per day on higher-
volume minor-street approact
(one direction only)
URBAN ...................... RURAL .......................
1. Minimum Vehicular
Sat id ied Not Satisfied
Number of lanes for moving traffic on each approach
Major Street Minor Street
1 .......................... 1 ...........................
2 ormore ................. 1 ...........................
2 or more ................. 2 or more ..................
1 .......................... 2 or more ..................
2. Interruption of Continuous Traffic
Satisfied Not Satisfied
Number of lanes for moving traffic on each approach
Major Street Minor Street
1 ......................... 1 ..........................
2 or more ................. 1 ..........................
2 ormore ................. 2 ormore ..................
1 .......................... 2 or more ..................
3. Combination
Satisfied Not Sat Id id
No one warrant satisfied but following warrants fulfilled
80% or more ............ 1 2
NOTE:
Minimum Requirements
EADT
Urban Rural
12,000 8.400
14.400 10.080
1 4,400 10,080
12,000 8,400
Urban Rural
1,200 850
1,200 850
1,600 1,120
1,600 1,120
2 Warrants 2 Warrants
1. Heavier left turn movement from the major street may be included with minor street volume if a separate
2. To be used only for NEW INTERSECTIONS or other locations where actual traffic volumes cannot
signal phase is to be provided for the left-turn movement
be counted.
N-IO0
Traffic Manual TRAFFIC SIGNALS AND LIGHTING 94
12-1-
I
. PARTA
Vehicle Volume
School Age Pedestrian Crossina Street
Flqun 0-1 E
SCHOOL PROTECTION WARRANTS
Minimum Requirements
UR
200 140 2 hours
Each of 40 40 2 hours
SATISFIED YES 0 NO 0
CALC DATE ---- CHK DATE DtST CO RTE P.M.
Major St: Critical Approach Speed mph
Minor St: Critical Approach Speed mph 8 RURAL(R)
0 URBAN(U)
Critical speed of approach traffic 240 mph
In built up area of isolated community of c 10,000 pop.
........................... ------------
FLASHING YELLOW SCHOOL SIGNALS
(All parts must be satisfied)
SATISFIED YES 0 NO 0
PART B
Critlcal Approach Speed Exceeds 35 mph SATISFIED YES 0 NO 0
AND
PART C
Is nearest controlled crossing moro than 600 feet away? SATISFIED YES 0 NO 0
SCHOOL AREA TRAFFIC SIGNALS
(All part8 mu8t be satisfied)
SATISFIED YES 0 NO 0
SATISFIED YES 0 NO 0
Crossing Street
AN0
PART €4 ~- ~
Is nearest controlled crossing moro thrn 600 feet away? SATISFIED YES 0 NO 0
9-10 TRAFFIC SIGNALS AND LIGHTING Traffic Manual
12-11#8
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, LIS TRAFFIC SIGNALS AND LIGHTING Traffic Manual
12-1-
I P E DESTRl ANS
TOTAL PEAK
F igun 9-3
DIRECTIONAL TRAFFIC COUNT SHEET
--__ _____I
DAY DATE
1 NO OFLANES
-4 '. I
I 1 ----- NO OFLANES HOUR TO wou R
FORM TS! 1