CMF / CRF Details
CMF ID: 7979
Install a traffic signal and left turn lanes
Description: Install a traffic signal and left turn lanes
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: | [View score details] |
Rating Points Total: | 120 |
Crash Modification Factor (CMF) | |
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Value: | 0.424 |
Adjusted Standard Error: | |
Unadjusted Standard Error: | 0.028 |
Crash Reduction Factor (CRF) | |
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Value: | 57.6 (This value indicates a decrease in crashes) |
Adjusted Standard Error: | |
Unadjusted Standard Error: | 2.8 |
Applicability | |
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Crash Type: | Other |
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: | 4-leg |
Traffic Control: | Stop-controlled |
Major Road Traffic Volume: | Minimum of 1360 to Maximum of 15500 Annual Average Daily Traffic (AADT) |
Minor Road Traffic Volume: | Minimum of 1036 to Maximum of 8884 Annual Average Daily Traffic (AADT) |
Average Major Road Volume : | 8555 Annual Average Daily Traffic (AADT) |
Average Minor Road Volume : | 3997 Annual Average Daily Traffic (AADT) |
Development Details | |
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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): | 762 crashes before, 310 crashes after |
Sample Size (sites): | 48 sites before, 48 sites after |
Sample Size (site-years): | 238 site-years before, 228 site-years after |