CMF / CRF Details

CMF ID: 7984

Install a traffic signal


Prior Condition: Intersections with a stop sign on minor roads

Category: Intersection traffic control

Study: Safety Evaluation of Signal Installation With and Without Left Turn Lanes on Two Lane Roads in Rural and Suburban Areas, Srinivasan et al., 2014

Star Quality Rating: 4 Stars   [View score details]
Crash Modification Factor (CMF)
Value: 0.601
Adjusted Standard Error:
Unadjusted Standard Error: 0.052
Crash Reduction Factor (CRF)
Value: 39.9   (This value indicates a decrease in crashes)
Adjusted Standard Error:
Unadjusted Standard Error: 5.2
Crash Type: All
Crash Severity: K (fatal),A (serious injury),B (minor injury),C (possible injury)
Roadway Types: Not specified
Number of Lanes: 2
Road Division Type:
Speed Limit:
Area Type: All
Traffic Volume:
Average Traffic Volume:
Time of Day: All
If countermeasure is intersection-based
Intersection Type: Not specified
Intersection Geometry: 4-leg
Traffic Control: Stop-controlled
Major Road Traffic Volume: Minimum of 2480 to Maximum of 17566 Annual Average Daily Traffic (AADT)
Minor Road Traffic Volume: Minimum of 746 to Maximum of 5803 Annual Average Daily Traffic (AADT)
Average Major Road Volume : 6338 Annual Average Daily Traffic (AADT)
Average Minor Road Volume : 3059 Annual Average Daily Traffic (AADT)
Development Details
Date Range of Data Used: 1992 to 2012
State: NC
Type of Methodology Used: Before/after using empirical Bayes or full Bayes
Sample Size (crashes): 368 crashes before, 192 crashes after
Sample Size (sites): 33 sites before, 33 sites after
Sample Size (site-years): 158 site-years before, 157 site-years after
Other Details
Included in Highway Safety Manual? No
Date Added to Clearinghouse: Nov-10-2016
Comments: The CMF was developed for both rural and suburban areas.