CMF / CRF Details
Change permissive left-turn phasing to protected only or protected/permissive
Countermeasure ID: 9889
Description: Treatment group includes intersections where signal phases were changed from permissive to protected-only or protected/permissive.
Prior Condition: Intersections with permissive left-turn signal phasing.
Category: Intersection traffic control
Study: Safety Evaluation of Protected Left-Turn Phasing and Leading Pedestrian Intervals on Pedestrian Safety, Goughnour et al., 2018
| Crash Modification Factor (CMF) |
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| Value: | 1.031 |
| Adjusted Standard Error: | |
| Unadjusted Standard Error: | 0.04 |
| Crash Reduction Factor (CRF) |
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| Value: | -3.1 (This value indicates an increase in crashes) |
| Adjusted Standard Error: | |
| Unadjusted Standard Error: | 4 |
| Applicability |
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| Crash Type: | Other |
| Crash Severity: | All |
| Roadway Types: | All |
| 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: | |
| Traffic Volume: | |
| Average Traffic Volume: | |
| Time of Day: | All |
| If countermeasure is intersection-based |
| Intersection Type: | Roadway/roadway (not interchange related) |
| Intersection Geometry: | Not specified |
| Traffic Control: | Signalized |
| Major Road Traffic Volume: | Minimum of 9912 to Maximum of 36500 Annual Average Daily Traffic (AADT) |
| Minor Road Traffic Volume: | Minimum of 4133 to Maximum of 26148 Annual Average Daily Traffic (AADT) |
| Average Major Road Volume : | 19546 Annual Average Daily Traffic (AADT) |
| Average Minor Road Volume : | 12917 Annual Average Daily Traffic (AADT) |
| Development Details |
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| Date Range of Data Used: | 2005 to 2014 |
| Municipality: | Chicago |
| State: | IL |
| Country: | |
| Type of Methodology Used: | Before/after using empirical Bayes or full Bayes |
| Sample Size (crashes): | 2083 crashes before, 1166 crashes after |
| Sample Size (sites): | 27 sites before, 27 sites after |
| Other Details |
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| Included in Highway Safety Manual? | No |
| Date Added to Clearinghouse: | Mar 11, 2019 |
| Comments: | Crash Type = Vehicle-Vehicle Crashes |
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