CMF / CRF Details
CMF ID: 6864
Widen Narrow Pavement
Description: Widen narrow pavement through wider lanes and/or shoulders
Prior Condition: Total pavement width of 18 to 22 ft
Category: Roadway
Study: Empirical Bayes Before-After Study on Safety Effect of Narrow Pavement Widening Projects in Texas, Wu et al., 2015
| Star Quality Rating: |  [View score details] |
| Rating Points Total: | 120 |
| Crash Modification Factor (CMF) | |
|---|---|
| Value: | 0.446 |
| Adjusted Standard Error: | |
| Unadjusted Standard Error: | 0.154 |
| Crash Reduction Factor (CRF) | |
|---|---|
| Value: | 55.4 (This value indicates a decrease in crashes) |
| Adjusted Standard Error: | |
| Unadjusted Standard Error: | 15.4 |
| Applicability | |
|---|---|
| Crash Type: | Head on |
| Crash Severity: | All |
| Roadway Types: | Not specified |
| 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: | |
| Maximum Speed Limit: | |
| Speed Unit: | |
| Speed Limit Comment: | |
| Area Type: | Rural |
| Traffic Volume: | Minimum of 487 to Maximum of 7417 Annual Average Daily Traffic (AADT) |
| Average Traffic Volume: | 2573 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: | 2003 to 2012 |
| Municipality: | |
| State: | TX |
| Country: | USA |
| Type of Methodology Used: | Before/after using empirical Bayes or full Bayes |
| Sample Size (crashes): | 22 crashes before, 10 crashes after |
| Sample Size (sites): | 22 sites before, 22 sites after |
| Sample Size (site-years): | 91.67 site-years before, 99 site-years after |
| Sample Size (miles): | 77.88 miles before, 77.88 miles after |
| Sample Size (miles): | 324.5 mile-years before, 350.5 mile-years after |
