CMF / CRF Details

CMF ID: 324

Install a traffic signal (major road speed limit at least 40 mph)

Description: Install a traffic signal (major road speed limit at least 40 mph)

Prior Condition: No Prior Condition(s)

Category: Intersection traffic control

Study: Safety Effects of Left-Turn Phasing Schemes at High-Speed Intersections, Davis and Aul, 2007

Star Quality Rating: 3 Stars
Crash Modification Factor (CMF)
Value: 2.43
Adjusted Standard Error: 0.37
Unadjusted Standard Error: 0.31
Crash Reduction Factor (CRF)
Value: -143   (This value indicates an increase in crashes)
Adjusted Standard Error: 37
Unadjusted Standard Error: 31
Crash Type: Rear end
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:
If countermeasure is intersection-based
Intersection Type: Roadway/roadway (not interchange related)
Intersection Geometry: 4-leg
Traffic Control: Stop-controlled
Major Road Traffic Volume:
Minor Road Traffic Volume:
Average Major Road Volume :
Average Minor Road Volume :
Development Details
Date Range of Data Used:
Type of Methodology Used: Before/after using empirical Bayes or full Bayes
Other Details
Included in Highway Safety Manual? Yes. HSM lists this CMF in italics font to indicate that it has a lower reliability than bold font CMFs since it has an adjusted standard error of 0.2 to 0.3.
Date Added to Clearinghouse: Dec-01-2009
Comments: Countermeasure name changed to match HSM