The MUTCD’s signal warrants are guidelines for transportation professionals on installing signs and signals on roadways. Part 4 of the MUTCD covers the criteria for highway traffic signals. The 11th Edition of the MUTCD has updated the information used to evaluate if a signal is warranted at an intersection.
This blog will share the key changes to note in MUTCD’s 11th Edition.
Key Changes to Signal Warrants in MUTCD 11th edition
One of the main changes in the 11th Edition is that satisfying a signal warrant is not the only factor in determining the installation of a traffic signal. There was always some discretion applied when a signal warrant was met, but now agencies can install signals where no warrants are met or choose not to install a signal where warrants are met.
The changes to signal Warrant 7 include new warrant criteria for a variety of scenarios.
Previously, the Warrant 7 criteria stated that a traffic signal should be considered if:
- A trial of alternatives and enforcement doesn’t reduce crash frequency
- Five or more crashes are reported in a 12-month period that are correctable by a traffic signal
- The 8-hour vehicle warrant is satisfied, or the volume of pedestrian traffic is not less than 80 percent of the requirements
New criteria for Signal Warrant 7 in the 11th Edition:
- Three vs. four-leg intersections
- Based on severity
- For speeds greater than 40 mph and populations < 10,000
- Thresholds based on HSM methodology for typical intersections (option to apply agency-specific crash frequencies)
The expanded criteria allow for the installation of traffic signals in more applications, rather than applying a blanket standard for all intersections, crash types, and severities. The new crash thresholds were developed using the safety performance functions (SPFs) in the Highway Safety Manual (HSM) for stop-controlled and signalized intersections with typical characteristics. Agencies can calibrate their own crash data to produce agency-specific SPFs and crash frequency values, providing additional flexibility.
Additional Resources from the ITE
On July 31, 2024, the Institute of Transportation Engineers hosted a webinar titled Updates to the Signal Warrant Process and the Revision to Warrant 7. Webinar topics included:
- Basics of the MUTCD
- Changes to the signal warrants in the 11th edition, specifically Warrant 7
- Obtaining crash data for Warrant 7
The webinar also discussed more changes to the signal warrants and the process behind the MUTCD updates. ITE members can view the webinar for free.
