CMF / CRF Details

CMF ID: 4887

Replace Night-Time Flash with Steady Operation


Prior Condition: Traffic signals were operating in the late night flash (LNF) mode from late night to early morning hours.

Category: Intersection traffic control

Study: Safety Evaluation of Discontinuing Late Night Flash Operations at Signalized Intersections, Lan and Srinivasan, 2013

Star Quality Rating: 4 Stars   [View score details]
Rating Points Total: 120
Crash Modification Factor (CMF)
Value: 0.52
Adjusted Standard Error:
Unadjusted Standard Error: 0.06
Crash Reduction Factor (CRF)
Value: 48   (This value indicates a decrease in crashes)
Adjusted Standard Error:
Unadjusted Standard Error: 6
Crash Type: All
Crash Severity: All
Roadway Types: All
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: All
Minimum Speed Limit:
Maximum Speed Limit:
Speed Unit:
Speed Limit Comment:
Area Type: All
Traffic Volume:
Average Traffic Volume:
Time of Day: Night
If countermeasure is intersection-based
Intersection Type: Not specified
Intersection Geometry: 3-leg,4-leg
Traffic Control: Signalized
Major Road Traffic Volume: Minimum of 2550 to Maximum of 59000 Annual Average Daily Traffic (AADT)
Minor Road Traffic Volume: Minimum of 1000 to Maximum of 23333 Annual Average Daily Traffic (AADT)
Average Major Road Volume : 21837 Annual Average Daily Traffic (AADT)
Average Minor Road Volume : 7955 Annual Average Daily Traffic (AADT)
Development Details
Date Range of Data Used: 2000 to 2007
Municipality: Statewide
State: NC
Country: USA
Type of Methodology Used: Before/after using empirical Bayes or full Bayes
Sample Size (crashes): 482 crashes before, 86 crashes after
Other Details
Included in Highway Safety Manual? No
Date Added to Clearinghouse: Aug-01-2013
Comments: The study reports CRFs using 3 methods (univariate EB, univariate FB, and multivariate FB). The authors concluded that the multivariate FB gives the most accurate results. The summary statistics are approximations because 4 sites were removed from the final analysis and the final summary statistics were not provided.