CMF / CRF Details
CMF ID: 4080
Upgrade unpaved or non-existent shoulders to composite shoulders
Description:
Upgrade shoulders on rural two-lane roads from unpaved or non-existent shoulders to composite shoulders.
Prior Condition: Unpaved shoulders less than or equal to 5 feet on rural two-lane roads.
Category: Shoulder treatments
| Crash Modification Factor (CMF) |
|---|
| Value: | 0.389 |
| Adjusted Standard Error: | |
| Unadjusted Standard Error: | 0.13 |
| Crash Reduction Factor (CRF) |
|---|
| Value: | 61.1 (This value indicates a decrease in crashes) |
| Adjusted Standard Error: | |
| Unadjusted Standard Error: | 13 |
| Applicability |
|---|
| Crash Type: | Head on,Run off road,Sideswipe |
| 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 380 to Maximum of 2340 Average Daily Traffic (ADT) |
| Average Traffic Volume: | 980 Average Daily Traffic (ADT) |
| 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: | 2000 to 2009 |
| Municipality: | |
| State: | KS |
| Country: | USA |
| Type of Methodology Used: | Before/after using empirical Bayes or full Bayes |
| Sample Size (crashes): | 13 crashes before, 12 crashes after |
| Other Details |
|---|
| Included in Highway Safety Manual? | No |
| Date Added to Clearinghouse: | Nov 01, 2012 |
| Comments: | In this study, the treatment group was found to be not represented well by the reference group with respect to FI crashes and related crashes. Two EB results were combined to make the final estimates: one used separate SPFs for each type of studied crash, and the other one used the same SPF for all crash types, which performed similarly in both the reference and treatment groups. The combined EB resulted in better estimates with lower standard errors.This CMF is also contained in the report, Zeng, H., S. Schrock, and T. Mulinazzi. "Evaluation of Safety Effectiveness of Composite Shoulders, Wide Unpaved Shoulders, and Wide Paved Shoulders in Kansas," Report No. K-TRAN: KU-11-1, Kansas DOT, Topeka, KS, March 2013. |
[View score details]