MUTCD Warrants and Signalization
What is a signal warrant?
A warrant is a condition that an intersection must meet to justify a signal installation. The Manual on Uniform Traffic Control Devices (MUTCD) specifies eight "traffic control signal needs studies", known as warrants. However, "The satisfaction of a traffic signal warrant or warrants shall not in itself require the installation of a traffic control signal." (MUTCD, 4C.01) The final decision is made based upon the traffic engineer's judgment.
Process to determine if signal is warranted
The traffic engineer analyzes vehicle traffic volume, pedestrian activity, intersection crash history, and the physical environment in order to determine whether or not the intersection warrants a traffic control signal.
Engineers examining the intersection may review the following:
- Number of vehicles entering the intersection from all directions during 4-hour and 8-hour periods
- Vehicular volumes during peak hours, classified by vehicle type for traffic movement in all directions
- Pedestrian volume on each crosswalk in all directions, including children, the elderly, and/or persons with disabilities, during each hour of the day
- Requests from participants attending nearby facilities and activity centers that serve the young, elderly, and/or persons with disabilities
- Posted speed limit
- Physical layout
- Crash experience/history
Different warrants require detailed analysis of different aspects of the above information.
Examples of Signal Warrants
Information on two of the signal warrants is included below to illustrate some of the considerations.
Warrant 1- Eight- Hour Vehicular Volume
Engineers evaluate the vehicles per hour and a certain volume must be met in order to justify installation. A complex table is used that includes the number of lanes of moving traffic for each approach, vehicles per hour on the major street, and vehicles per hour on the higher volume minor street approaches.
Standard (MUTCD, Section 4C.02):
The need for a traffic control signal shall be considered if an engineering study finds that one of the following conditions exist for each of any 8 hours of an average day (See Table 3-1):
- The vehicles per hour given in both of the 100 percent columns of Condition A in Table 3-1 exist on the major-street and the higher-volume minor-street approaches, respectively, to the intersection; or
- The vehicles per hour given in both of the 100 percent columns of Condition B in Table 3-1 exist on the major-street and the higher-volume minor-street approaches, respectively, to the intersection.
In applying each condition the major-street and minor-street volumes shall be for the same 8 hours. On the minor street, the higher volume shall not be required to be on the same approach during each of these 8 hours.
Option: If the posted or statutory speed limit or the 85th-percentile speed on the major street exceeds 70 km/h (40 mph), or if the intersection lies within the built-up area of an isolated community having a population of less than 10,000, the traffic volumes in the 70 percent columns in Table 3-1 may be used in place of the 100 percent columns.
Table 3-1. Example of Signal Warrant 1
|
Condition A —Minimum Vehicular Volume |
|||||||
|---|---|---|---|---|---|---|---|
Number of lanes for moving traffic on each approach |
Vehicles per hour on major street (total of both approaches) |
Vehicles per hour on higher-volume minor-street approaches (one direction only) |
|||||
|
Major Street |
Minor Street |
100%a |
80%b |
70%c |
100%a |
80%b |
70%c |
|
1 |
1 |
500 |
400 |
350 |
150 |
120 |
105 |
|
2 or more |
1 |
600 |
480 |
420 |
150 |
120 |
105 |
|
2 or more |
2 or more |
600 |
480 |
420 |
200 |
160 |
140 |
|
1 |
2 or more |
500 |
400 |
350 |
200 |
160 |
140 |
|
Condition B—Interruption of Continuous Traffic |
|||||||
|
Number of lanes for moving traffic on each approach |
Vehicles per hour on major street (total of both approaches) |
Vehicles per hour on higher-volume minor-street approaches (one direction only) |
|||||
|
Major Street |
Minor Street |
100%a |
80%b |
70%c |
100%a |
80%b |
70%c |
|
1 |
1 |
750 |
600 |
525 |
75 |
60 |
53 |
|
2 or more |
1 |
900 |
720 |
630 |
75 |
60 |
53 |
|
2 or more |
2 or more |
900 |
720 |
630 |
100 |
80 |
70 |
|
1 |
2 or more |
750 |
600 |
525 |
100 |
80 |
70 |
|
bUsed for combination of Conditions A and B after adequate trial of other remedial measures. cMay be used when the major-street speed exceeds 70 km/h (40 mph) or in an isolated community with a population of less than |
|||||||
Warrant 4 " Pedestrian Volume
Engineers evaluate the level of pedestrian activity at an intersection to see if a signal is warranted. The MUTCD describes Warrant 4 as "The Pedestrian Volume signal warrant is intended for application where the traffic volume on a major street is so heavy that pedestrians experience excessive delay in crossing the major street." (MUTCD, 4C.05)
As currently written, the warrant requires a fairly large volume of pedestrians crossing at a location.
"The need for a traffic control signal at an intersection or mid-block crossing shall be considered if an engineering study finds that both of the following criteria are met:
- The pedestrian volume crossing the major street at an intersection or mid-block location during an average day is 100 or more for each of any 4 hours or 190 or more during any 1 hour; and
- There are fewer than 60 gaps per hour in the traffic stream of adequate length to allow pedestrians to cross during the same period when the pedestrian volume criterion is satisfied. Where there is a divided street having a median of sufficient width for pedestrians to wait, the requirement applies separately to each direction of vehicular traffic." (MUTCD, 4C.05)
In addition:
- "The Pedestrian Volume signal warrant shall not be applied at locations where the distance to the nearest traffic control signal along the major street is less than 90 m (300 ft), unless the proposed traffic control signal will not restrict the progressive movement of traffic." (MUTCD, 4C.05)
However:
- "The criterion for the pedestrian volume crossing the major roadway may be reduced as much as 50 percent if the average crossing speed of pedestrians is less than 1.2 m/sec (4 ft/sec)." (MUTCD, 4C.05)
For more information
The current MUTCD can be downloaded from the following website:
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