CMF / CRF Details
CMF ID: 9221
Install safety edge treatment
Description: The safety edge is a low-cost treatment that is implemented in conjunction with pavement resurfacing and is intended to help minimize drop-off-related crashes.
Prior Condition: Drop-off pavement edge
Category: Shoulder treatments
Study: Development Of Crash Modification Factors For The Application Of The Safetyedge Treatment On Two-Lane Rural Roads, Donnell et al., 2017
| Star Quality Rating: |  [View score details] |
| Rating Points Total: | 140 |
| Crash Modification Factor (CMF) | |
|---|---|
| Value: | 0.655 |
| Adjusted Standard Error: | |
| Unadjusted Standard Error: | 0.064 |
| Crash Reduction Factor (CRF) | |
|---|---|
| Value: | 34.5 (This value indicates a decrease in crashes) |
| Adjusted Standard Error: | |
| Unadjusted Standard Error: | 6.4 |
| Applicability | |
|---|---|
| Crash Type: | Other |
| Crash Severity: | All |
| Roadway Types: | Principal Arterial Other |
| 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: | Rural |
| Traffic Volume: | Minimum of 10 to Maximum of 18600 Annual Average Daily Traffic (AADT) |
| Average Traffic Volume: | 3175 Annual Average Daily Traffic (AADT) |
| Time of Day: | Not specified |
| If countermeasure is intersection-based | |
| Intersection Type: | |
| Intersection Geometry: | |
| Traffic Control: | |
| Major Road Traffic Volume: | |
| Minor Road Traffic Volume: | |
| Average Major Road Volume : | |
| Average Minor Road Volume : | |
| Development Details | |
|---|---|
| Date Range of Data Used: | 2005 to 2014 |
| Municipality: | |
| State: | IA,NC,OH |
| Country: | |
| Type of Methodology Used: | Before/after using empirical Bayes or full Bayes |
| Sample Size (crashes): | 457 crashes before, 115 crashes after |
| Sample Size (sites): | 1453 sites before, 1453 sites after |
| Sample Size (miles): | 1261 miles before, 1261 miles after |
| Sample Size (miles): | 7230 mile-years before, 2759 mile-years after |
