CMF / CRF Details
CMF ID: 4114
Install icy curve warning system
Description: Installation of icy curve warning system (ICWS)
Prior Condition: Roadway without icy curve warning system
Category: Advanced technology and ITS
Study: Safety Effects of Icy Curve Warning Systems, Zhirui et al., 2012
Image: View the countermeasure image.
| Star Quality Rating: |  [View score details] |
| Rating Points Total: | 85 |
| Crash Modification Factor (CMF) | |
|---|---|
| Value: | 0.82 |
| Adjusted Standard Error: | |
| Unadjusted Standard Error: | 0.08 |
| Crash Reduction Factor (CRF) | |
|---|---|
| Value: | 18 (This value indicates a decrease in crashes) |
| Adjusted Standard Error: | |
| Unadjusted Standard Error: | 8 |
| Applicability | |
|---|---|
| Crash Type: | All |
| Crash Severity: | All |
| Roadway Types: | Not Specified |
| Street Type: | |
| Minimum Number of Lanes: | 2 |
| Maximum Number of Lanes: | 4 |
| Number of Lanes Direction: | |
| Number of Lanes Comment: | |
| Crash Weather: | Not specified |
| Road Division Type: | All |
| Minimum Speed Limit: | 40 |
| Maximum Speed Limit: | 55 |
| Speed Unit: | mph |
| Speed Limit Comment: | |
| Area Type: | Rural |
| Traffic Volume: | Minimum of 2850 to Maximum of 2950 Average Daily Traffic (ADT) |
| Average Traffic Volume: | 2900 Average Daily Traffic (ADT) |
| 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: | 1998 to 2009 |
| Municipality: | Lassen County |
| State: | CA |
| Country: | |
| Type of Methodology Used: | Before/after using empirical Bayes or full Bayes |
| Sample Size (crashes): | 56 crashes before, 18 crashes after |
