CMF / CRF Details

CMF ID: 4207

Increase yellow change interval


Prior Condition:  Signalized intersection with yellow interval and most sites had an all red interval. The increase in yellow time was 1.0 second in all the sites.

Category: Intersection traffic control

Study: Evaluation of Safety Strategies at Signalized Intersections, Srinivasan, et al., 2011

Star Quality Rating:3 Stars  [View score details]
Rating Points Total:90
Crash Modification Factor (CMF)
Adjusted Standard Error:
Unadjusted Standard Error:0.177
Crash Reduction Factor (CRF)
Value:-14.1  (This value indicates an increase in crashes)
Adjusted Standard Error:
Unadjusted Standard Error:17.7
Crash Type:All
Crash Severity:All
Roadway Types:Not Specified
Street Type:
Minimum Number of Lanes:
Maximum Number of Lanes:
Number of Lanes Direction:
Number of Lanes Comment:
Crash Weather:Not specified
Road Division Type:
Minimum Speed Limit:
Maximum Speed Limit:
Speed Unit:
Speed Limit Comment:
Area Type:Urban
Traffic Volume:
Average Traffic Volume:
Time of Day:All
If countermeasure is intersection-based
Intersection Type:Roadway/roadway (not interchange related)
Intersection Geometry:3-leg,4-leg
Traffic Control:Signalized
Major Road Traffic Volume:Minimum of 5950 to Maximum of 31600 Annual Average Daily Traffic (AADT)
Minor Road Traffic Volume:Minimum of 2650 to Maximum of 20225 Annual Average Daily Traffic (AADT)
Average Major Road Volume :17417 Annual Average Daily Traffic (AADT)
Average Minor Road Volume :8484 Annual Average Daily Traffic (AADT)
Development Details
Date Range of Data Used:1992 to 2002
Municipality:San Diego, San Francisco, Howard County, and Montgomery County
Type of Methodology Used:Before/after using empirical Bayes or full Bayes
Sample Size (sites):5 sites after
Other Details
Included in Highway Safety Manual?No
Date Added to Clearinghouse:Dec 06, 2012
Comments:Assumed 2 crashes per site for both the before and after periods to estimate sample size.