CMF / CRF Details
CMF ID: 8497
Change right-turn lane geometry to increase line of sight (intersection level)
Description: Changes made to study approaches include: sharpening the flat approach angle typical in the traditional design, reducing the radius, adjusting the stop/yield bar position, and/or modifying the corner island to improve safety by increasing the line of sight of approaching through traffic.
Prior Condition: Traditional right-turn lane design
Category: Intersection geometry
Study: Effectiveness Evaluation of a Modified Right-Turn Lane Design at Intersections, Schattler et al., 2016
| Star Quality Rating: |  [View score details] |
| Rating Points Total: | 115 |
| Crash Modification Factor (CMF) | |
|---|---|
| Value: | 0.564 |
| Adjusted Standard Error: | |
| Unadjusted Standard Error: | 0.161 |
| Crash Reduction Factor (CRF) | |
|---|---|
| Value: | 43.6 (This value indicates a decrease in crashes) |
| Adjusted Standard Error: | |
| Unadjusted Standard Error: | 16.14 |
| Applicability | |
|---|---|
| Crash Type: | All |
| Crash Severity: | K (fatal),A (serious injury),B (minor injury),C (possible injury) |
| 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: | 25 |
| Maximum Speed Limit: | 45 |
| Speed Unit: | mph |
| Speed Limit Comment: | |
| Area Type: | |
| Traffic Volume: | |
| Average Traffic Volume: | |
| Time of Day: | |
| If countermeasure is intersection-based | |
| Intersection Type: | Other |
| Intersection Geometry: | 3-leg,4-leg |
| Traffic Control: | Other |
| 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 2014 |
| Municipality: | |
| State: | IL |
| Country: | |
| Type of Methodology Used: | Before/after using empirical Bayes or full Bayes |
| Sample Size (crashes): | 64 crashes before, 39 crashes after |
| Sample Size (sites): | 6 sites before, 6 sites after |
| Sample Size (site-years): | 18 site-years before, 18 site-years after |
