CMF / CRF Details
CMF ID: 8662
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: Roadway without safety edge
Category: Shoulder treatments
Study: Safety Edge Crash Modification Factors, Hallmark et al., 2016
| Star Quality Rating: |  [View score details] |
| Rating Points Total: | 110 |
| Crash Modification Factor (CMF) | |
|---|---|
| Value: | 0.92 |
| Adjusted Standard Error: | |
| Unadjusted Standard Error: | 0.121 |
| Crash Reduction Factor (CRF) | |
|---|---|
| Value: | 8 (This value indicates a decrease in crashes) |
| Adjusted Standard Error: | |
| Unadjusted Standard Error: | 12.1 |
| Applicability | |
|---|---|
| Crash Type: | Run off road |
| Crash Severity: | K (fatal),A (serious injury),B (minor injury),C (possible injury) |
| Roadway Types: | All |
| 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: | Undivided |
| Minimum Speed Limit: | 45 |
| Maximum Speed Limit: | |
| Speed Unit: | mph |
| Speed Limit Comment: | > = 45 mph |
| Area Type: | Rural |
| Traffic Volume: | Minimum of 25 to Maximum of 2500 Annual Average Daily Traffic (AADT) |
| Average Traffic Volume: | 1406 Annual Average Daily Traffic (AADT) |
| Time of Day: | All |
| 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: | 2004 to 2014 |
| Municipality: | |
| State: | IA |
| Country: | USA |
| Type of Methodology Used: | Before/after using empirical Bayes or full Bayes |
| Sample Size (crashes): | 58 crashes after |
| Sample Size (sites): | 659 sites before, 659 sites after |
| Sample Size (miles): | 418 miles before, 418 miles after |
| Other Details | |
|---|---|
| Included in Highway Safety Manual? | No |
| Date Added to Clearinghouse: | Nov 06, 2017 |
| Comments: | CMFs of crashes where ROR right, ROR straight, or ROR left was listed in the sequence of events. |
