CMF / CRF Details
CMF ID: 9219
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
| Crash Modification Factor (CMF) |
|---|
| Value: | 0.628 |
| Adjusted Standard Error: | |
| Unadjusted Standard Error: | 0.072 |
| Crash Reduction Factor (CRF) |
|---|
| Value: | 37.2 (This value indicates a decrease in crashes) |
| Adjusted Standard Error: | |
| Unadjusted Standard Error: | 7.2 |
| 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: | NC |
| Country: | |
| Type of Methodology Used: | Before/after using empirical Bayes or full Bayes |
| Sample Size (crashes): | 309 crashes before, 82 crashes after |
| Sample Size (sites): | 727 sites before, 727 sites after |
| Sample Size (miles): | 369 miles before, 369 miles after |
| Sample Size (miles): | 2375 mile-years before, 948 mile-years after |
| Other Details |
|---|
| Included in Highway Safety Manual? | No |
| Date Added to Clearinghouse: | Jun 17, 2018 |
| Comments: | Drop-off-related crashes were defined where the roadway contributing circumstance variable was coded to indicate that the shoulder was low, soft or high, or, the sequence of events indicated one of the following events:ROR-R followed by ROR-L; ROR-R followed by overturn/rollover; ROR-R followed by cross centerline/median. Excludes intersection-related crashes and animal-related crashes. |
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