CMF / CRF Details
Changing left turn phasing from protected-permissive to flashing yellow arrow (FYA)
Countermeasure ID: 9667
Description: CMFs are calculated the intersection level and not the treated approach(es) level.
Prior Condition: Protected-permissive operation with circular green indication for the permissive
Category: Intersection traffic control
Study: Safety Effects of Flashing Yellow Arrows Used in Protected Permitted Phasing: Comparison of Full Bayes And Empirical Bayes Results, Appiah et al., 2018
| Crash Modification Factor (CMF) |
|---|
| Value: | 0.88 |
| Adjusted Standard Error: | |
| Unadjusted Standard Error: | 0.053 |
| Crash Reduction Factor (CRF) |
|---|
| Value: | 12 (This value indicates a decrease in crashes) |
| Adjusted Standard Error: | |
| Unadjusted Standard Error: | 5.3 |
| Applicability |
|---|
| Crash Type: | All |
| Crash Severity: | All |
| Roadway Types: | Not specified |
| 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: | All |
| Traffic Volume: | |
| Average Traffic Volume: | |
| Time of Day: | Not specified |
| If countermeasure is intersection-based |
| Intersection Type: | Roadway/roadway (not interchange related) |
| Intersection Geometry: | 3-leg,4-leg |
| Traffic Control: | Signalized |
| Major Road Traffic Volume: | Minimum of 3678 to Maximum of 28605 Annual Average Daily Traffic (AADT) |
| Minor Road Traffic Volume: | Minimum of 561 to Maximum of 8625 Annual Average Daily Traffic (AADT) |
| Average Major Road Volume : | 12226 Annual Average Daily Traffic (AADT) |
| Average Minor Road Volume : | 3383 Annual Average Daily Traffic (AADT) |
| Development Details |
|---|
| Date Range of Data Used: | 2008 to 2016 |
| Municipality: | |
| State: | VA |
| Country: | USA |
| Type of Methodology Used: | Before/after using empirical Bayes or full Bayes |
| Sample Size (crashes): | 685 crashes before, 203 crashes after |
| Sample Size (sites): | 28 sites before, 28 sites after |
| Sample Size (site-years): | 190 site-years before, 62 site-years after |
| Other Details |
|---|
| Included in Highway Safety Manual? | No |
| Date Added to Clearinghouse: | Oct 27, 2018 |
| Comments: | |
[View score details]