CMF / CRF Details
CMF ID: 7996
Install left-turn lane at signalized intersection
Description:
Prior Condition: Intersections without left turn lanes
Category: Intersection geometry
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: | [View score details] |
Rating Points Total: | 115 |
Crash Modification Factor (CMF) | |
---|---|
Value: | 0.748 |
Adjusted Standard Error: | |
Unadjusted Standard Error: | 0.095 |
Crash Reduction Factor (CRF) | |
---|---|
Value: | 25.2 (This value indicates a decrease in crashes) |
Adjusted Standard Error: | |
Unadjusted Standard Error: | 9.5 |
Applicability | |
---|---|
Crash Type: | All |
Crash Severity: | All |
Roadway Types: | Not specified |
Street Type: | |
Minimum Number of Lanes: | 2 |
Maximum Number of Lanes: | 2 |
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: | All |
Traffic Volume: | |
Average Traffic Volume: | |
Time of Day: | All |
If countermeasure is intersection-based | |
Intersection Type: | Not specified |
Intersection Geometry: | 3-leg |
Traffic Control: | Signalized |
Major Road Traffic Volume: | Minimum of 2981 to Maximum of 18248 Annual Average Daily Traffic (AADT) |
Minor Road Traffic Volume: | Minimum of 972 to Maximum of 13880 Annual Average Daily Traffic (AADT) |
Average Major Road Volume : | 9199 Annual Average Daily Traffic (AADT) |
Average Minor Road Volume : | 4847 Annual Average Daily Traffic (AADT) |
Development Details | |
---|---|
Date Range of Data Used: | 1992 to 2012 |
Municipality: | |
State: | NC |
Country: | |
Type of Methodology Used: | Before/after using empirical Bayes or full Bayes |
Sample Size (crashes): | 576 crashes before, 388 crashes after |
Sample Size (sites): | 36 sites before, 36 sites after |
Sample Size (site-years): | 180 site-years before, 174 site-years after |