CMF / CRF Details
CMF ID: 9167
Install in-lane curve warning pavement markings
Description: Pavement marking showing the word "Slow" and an arrow to alert drivers to an upcoming curve in the road.
Prior Condition: No Prior Condition(s)
Category: Delineation
Study: Safety Evaluation of Two Curve Warning Treatments: In-Lane Curve Warning Pavement Markings and Oversized Chevron Signs, Lyon et al., 2017
Image: View the countermeasure image.
| Star Quality Rating: |  [View score details] |
| Rating Points Total: | 115 |
| Crash Modification Factor (CMF) | |
|---|---|
| Value: | 0.616 |
| Adjusted Standard Error: | |
| Unadjusted Standard Error: | 0.092 |
| Crash Reduction Factor (CRF) | |
|---|---|
| Value: | 38.4 (This value indicates a decrease in crashes) |
| Adjusted Standard Error: | |
| Unadjusted Standard Error: | 9.2 |
| Applicability | |
|---|---|
| Crash Type: | All |
| Crash Severity: | All |
| Roadway Types: | Not specified |
| 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: | |
| Traffic Volume: | Minimum of 590 to Maximum of 7600 Annual Average Daily Traffic (AADT) |
| Average Traffic Volume: | |
| 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: | |
| Municipality: | |
| State: | IA,PA |
| Country: | USA |
| Type of Methodology Used: | Before/after using empirical Bayes or full Bayes |
| Sample Size (crashes): | 52 crashes before, 67 crashes after |
| Sample Size (miles): | 0.82 miles before, 0.82 miles after |
| Sample Size (miles): | 8.57 mile-years before, 17.37 mile-years after |
| Other Details | |
|---|---|
| Included in Highway Safety Manual? | No |
| Date Added to Clearinghouse: | Nov 17, 2017 |
| Comments: | Sample size is small, use with caution. Excludes intersection-related and animal-related crashes. |
