CMF / CRF Details
CMF ID: 5329
Install 10 mph differential speed limit on rural Interstate Highways
Description: Install a 10 mph differerntial speed limit on rural Interstate highways. The speed limit for passenger cars is 75 mph and is 65 for trucks.
Prior Condition: Equal posted speed limit for passenger cars and heavy trucks (both 65 and 75).
Category: Speed management
Study: Evaluation of the Impacts of Differential Speed Limits on Interstate Highways in Idaho, Dixon et al., 2012
| Star Quality Rating: |  [View score details] |
| Rating Points Total: | 105 |
| Crash Modification Factor (CMF) | |
|---|---|
| Value: | 0.914 |
| Adjusted Standard Error: | |
| Unadjusted Standard Error: | 0.051 |
| Crash Reduction Factor (CRF) | |
|---|---|
| Value: | 8.56 (This value indicates a decrease in crashes) |
| Adjusted Standard Error: | |
| Unadjusted Standard Error: | 5.06 |
| Applicability | |
|---|---|
| Crash Type: | All,Truck related |
| Crash Severity: | All |
| Roadway Types: | Principal Arterial Interstate |
| 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: | Rural |
| Traffic Volume: | |
| 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: | 1992 to 2011 |
| Municipality: | |
| State: | ID |
| Country: | |
| Type of Methodology Used: | Before/after using empirical Bayes or full Bayes |
