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]
Crash Modification Factor (CMF)
Value: 1.14
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
Number of Lanes:
Road Division Type:
Speed Limit:
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
State: CA, MD
Country: USA
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.