7B. Traffic Signal Warrant Flashcards
What is the primary purpose of “Warrants” in the MUTCD?
Warrants are criteria used to determine whether a traffic control device, such as a traffic signal, is needed at a particular location based on traffic conditions, safety concerns, and other factors.
What is Warrant 1, “Eight-Hour Vehicular Volume,” in the MUTCD used to determine?
Warrant 1 is used to determine whether a traffic signal is needed based on the vehicular volume during an eight-hour period. It considers the total volume of traffic at an intersection and compares it to pre-established thresholds. Found on Table 4C-1
Under Warrant 1, “Eight-Hour Vehicular Volume,” which two key conditions must be met to justify installing a traffic signal?
The need for a traffic control signal shall be considered if an engineering study finds that both of the following conditions exist for each of any 8 hours of an average day:
A. The vehicles per hour given in both of the 80 percent columns of Condition A in Table 4C-1 exist on the major-street and the higher-volume minor-street approaches, respectively, to the intersection; and
B. The vehicles per hour given in both of the 80 percent columns of Condition B in Table 4C-1 exist on the major-street and the higher-volume minor-street approaches, respectively, to the intersection.
These major-street and minor-street volumes shall be for the same 8 hours for each condition; however, the 8 hours satisfied in Condition A shall not be required to be the same 8 hours satisfied in Condition B.
On the minor street, the higher volume shall not be required to be on the same approach during each of
the 8 hours.
What is Warrant 2, “Four-Hour Vehicular Volume,” in the MUTCD used to evaluate?
Warrant 2 is similar to Warrant 1, but it uses a four-hour evaluation period instead of eight. It is used to assess the need for a traffic signal based on traffic volumes over a shorter time frame, typically during peak traffic periods.
What condition must be met for Warrant 2, “Four-Hour Vehicular Volume,” to justify a traffic signal? For Two-Lane Major Street (One lane in each direction):
The need for a traffic control signal shall be considered if an engineering study finds that, for each of any 4 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-volume minor-street approach (one direction only) all fall above the applicable curve in Figure 4C-1 for the existing combination of approach lanes.
What condition must be met for Warrant 2, “Four-Hour Vehicular Volume,” to justify a traffic signal? For Multi-Lane Major Street (Two or more lanes in each direction):
The volume of traffic on the major street during the four-hour period must meet specific thresholds, and the minor street volume must be less than a specified percentage of the major street volume.
Total Volume on Major Street (both directions):
The total volume of vehicles during the four-hour period should be at least 700 vehicles for multi-lane major streets (each direction combined).
Volume on Minor Street:
The volume on the minor street should be at least 100 vehicles per hour (VPH) during the peak period for a traffic signal to be warranted.
What is Warrant 3, “Peak Hour,” in the MUTCD used to evaluate?
Warrant 3 evaluates whether a traffic signal is needed during peak hours based on the traffic volume during the highest traffic period of the day (usually the busiest 60 minutes).
What condition must be met for Warrant 3, “Peak Hour,” to justify the installation of a traffic signal?
The need for a traffic control signal shall be considered if an engineering study finds that the criteria in either of the following two categories are met:
A. If all three of the following conditions exist for the same 1 hour (any four consecutive 15-minute periods) of an average day:
1. The total stopped time delay experienced by the traffic on one minor-street approach (one direction only) controlled by a STOP sign equals or exceeds: 4 vehicle-hours for a one-lane
approach or 5 vehicle-hours for a two-lane approach; and
2. The volume on the same minor-street approach (one direction only) equals or exceeds 100 vehicles per hour for one moving lane of traffic or 150 vehicles per hour for two moving lanes; and
3. The total entering volume serviced during the hour equals or exceeds 650 vehicles per hour for intersections with three approaches or 800 vehicles per hour for intersections with four or more approaches.
B. 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-volume minor-street approach (one
direction only) for 1 hour (any four consecutive 15-minute periods) of an average day falls above the applicable curve in Figure 4C-3 for the existing combination of approach lanes.
What is Warrant 4, “Intersection Pedestrian Volume,” in the MUTCD used to assess?
Warrant 4 is used to assess the need for a traffic signal based on pedestrian activity at an intersection. It applies when there is a high volume of pedestrians crossing a roadway, especially near schools or heavily pedestrianized areas.
What condition must be met under Warrant 4, “Intersection Pedestrian Volume,” to warrant a traffic signal?
The need for a traffic control signal at an intersection or midblock crossing shall be considered if an engineering study finds that one of the following criteria is met:
A. For each of any 4 hours of an average day, the plotted points representing the vehicles per hour on the major street (total of both approaches) and the corresponding pedestrians per hour crossing the major street (total of all crossings) all fall above the curve in Figure 4C-5; or
B. For 1 hour (any four consecutive 15-minute periods) of an average day, the plotted point representing the vehicles per hour on the major street (total of both approaches) and the corresponding pedestrians per hour crossing the major street (total of all crossings) falls above the curve in Figure 4C-7.
What is Warrant 5, “School Crossing,” in the MUTCD used for?
Warrant 5 is specifically for school crossings and evaluates whether a traffic signal is warranted at an intersection near a school based on the volume of pedestrians (children) crossing the street.
What is the threshold for Warrant 5, “School Crossing,” to justify installing a traffic signal?
The need for a traffic control signal shall be considered when an engineering study of the frequency and adequacy of gaps in the vehicular traffic stream as related to the number and size of groups of schoolchildren at an established school crossing across the major street shows that the number of adequate gaps in the traffic stream during the period when the schoolchildren are using the crossing is less than the number of minutes in the same period (see Section 7A.03) and there are a minimum of 20 schoolchildren during the highest crossing hour.
What is Warrant 6, “Coordinated Signal System,” in the MUTCD used to evaluate?
Warrant 6 evaluates the need for a traffic signal in a system of coordinated signals, particularly when installing a signal would improve the overall traffic flow of a series of intersections.
What must be true under Warrant 6, “Coordinated Signal System,” to justify a traffic signal?
The need for a traffic control signal shall be considered if an engineering study finds that one of the following criteria is met:
A. On a one-way street or a street that has traffic predominantly in one direction, the adjacent traffic control signals are so far apart that they do not provide the necessary degree of vehicular platooning.
B. On a two-way street, adjacent traffic control signals do not provide the necessary degree of platooning and the proposed and adjacent traffic control signals will collectively provide a progressive operation.
What is Warrant 7, “Crash Experience,” in the MUTCD used to evaluate?
Warrant 7 considers the crash history at an intersection to determine if a traffic signal should be installed. If there is a pattern of crashes that could be mitigated by a traffic signal, the warrant may be satisfied.
