CMF / CRF Details
Install safety edge treatment
Countermeasure ID: 9200
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
| Crash Modification Factor (CMF) |
|---|
| Value: | 0.842 |
| Adjusted Standard Error: | |
| Unadjusted Standard Error: | 0.101 |
| Crash Reduction Factor (CRF) |
|---|
| Value: | 15.8 (This value indicates a decrease in crashes) |
| Adjusted Standard Error: | |
| Unadjusted Standard Error: | 10.1 |
| Applicability |
|---|
| Crash Type: | All |
| Crash Severity: | K (fatal),A (serious injury),B (minor injury) |
| 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 724 to Maximum of 8000 Annual Average Daily Traffic (AADT) |
| Average Traffic Volume: | 1345 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: | 2007 to 2014 |
| Municipality: | |
| State: | IA |
| Country: | |
| Type of Methodology Used: | Before/after using empirical Bayes or full Bayes |
| Sample Size (crashes): | 161 crashes before, 141 crashes after |
| Sample Size (sites): | 279 sites before, 279 sites after |
| Sample Size (miles): | 316 miles before, 316 miles after |
| Sample Size (miles): | 1008 mile-years before, 1205 mile-years after |
| Other Details |
|---|
| Included in Highway Safety Manual? | No |
| Date Added to Clearinghouse: | Jun 17, 2018 |
| Comments: | Excludes intersection-related crashes and animal-related crashes |
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