CMF / CRF Details
CMF ID: 6048
Increase retroreflectivity of STOP signs
Description: Implementation of STOP signs with higher retroreflectivity
Prior Condition: Stop signs with low retroreflectivity
Category: Intersection traffic control
Study: Safety Evaluation of Increasing Retroreflectivity of STOP Signs, Persaud et al., 2007
| Star Quality Rating: |  [View score details] |
| Rating Points Total: | 110 |
| Crash Modification Factor (CMF) | |
|---|---|
| Value: | 0.924 |
| Adjusted Standard Error: | |
| Unadjusted Standard Error: | 0.076 |
| Crash Reduction Factor (CRF) | |
|---|---|
| Value: | 7.6 (This value indicates a decrease in crashes) |
| Adjusted Standard Error: | |
| Unadjusted Standard Error: | 7.6 |
| Applicability | |
|---|---|
| Crash Type: | Angle |
| Crash Severity: | All |
| Roadway Types: | All |
| 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: | All |
| If countermeasure is intersection-based | |
| Intersection Type: | |
| Intersection Geometry: | 3-leg,4-leg |
| Traffic Control: | Stop-controlled |
| Major Road Traffic Volume: | Minimum of 344 to Maximum of 57,353 Annual Average Daily Traffic (AADT) |
| Minor Road Traffic Volume: | Minimum of 206 to Maximum of 9,178 Annual Average Daily Traffic (AADT) |
| Average Major Road Volume : | 10,414 Annual Average Daily Traffic (AADT) |
| Average Minor Road Volume : | 2,139 Annual Average Daily Traffic (AADT) |
| Development Details | |
|---|---|
| Date Range of Data Used: | 1994 to 2005 |
| Municipality: | |
| State: | SC |
| Country: | |
| Type of Methodology Used: | Before/after using empirical Bayes or full Bayes |
| Sample Size (crashes): | 725 crashes before, 247 crashes after |
| Sample Size (sites): | 108 sites before, 108 sites after |
| Sample Size (site-years): | 906 site-years before, 379 site-years after |
| Other Details | |
|---|---|
| Included in Highway Safety Manual? | No |
| Date Added to Clearinghouse: | Dec 08, 2014 |
| Comments: | Crash type is right angle. The CMF is not significant at the 95% confidence level |
