CMF / CRF Details

CMF ID: 4854

Installation of an actuated advance warning dilemma zone protection system at high-speed signalized intersections

Description: Installation of an actuated advance warning dilemma zone protection system at high-speed signalized intersections. The design algorithm continually monitors an upstream detector as well as traffic at the intersection in order to predict the onset of the yellow signal indication. Flashing beacons are then used to get the driver's attention and also to warn the driver of the impending end of the green indication.

Prior Condition:  Untreated signalized intersection

Category: Intersection traffic control

Study: Safety Effect of Dilemma-Zone Protection Using Actuated Advance Warning Systems, Appiah et al., 2011

Star Quality Rating:3 Stars  [View score details]
Rating Points Total:75
Crash Modification Factor (CMF)
Adjusted Standard Error:
Unadjusted Standard Error:0.056
Crash Reduction Factor (CRF)
Value:43.6  (This value indicates a decrease in crashes)
Adjusted Standard Error:
Unadjusted Standard Error:5.6
Crash Type:Angle
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:Not specified
Traffic Volume:
Average Traffic Volume:
Time of Day:All
If countermeasure is intersection-based
Intersection Type:Roadway/roadway (not interchange related)
Intersection Geometry:4-leg
Traffic Control:Signalized
Major Road Traffic Volume:Minimum of 2420 to Maximum of 21477 Annual Average Daily Traffic (AADT)
Minor Road Traffic Volume:Minimum of 995 to Maximum of 8948 Annual Average Daily Traffic (AADT)
Average Major Road Volume :
Average Minor Road Volume :
Development Details
Date Range of Data Used:1996 to 2008
Type of Methodology Used:Before/after using empirical Bayes or full Bayes
Sample Size (crashes):262 crashes before, 191 crashes after
Other Details
Included in Highway Safety Manual?No
Date Added to Clearinghouse:May 01, 2013