CMF / CRF Details
CMF ID: 3141
Convert a Type I exit ramp to a Type IV exit ramp
Description: Type I is a full width parallel from tangent that leads to either a tangent or flat exiting curve which includes a decelerating taper. The horizontal and vertical alignment of type I exit ramps were based on the selected design speed equal or less than the intersecting roadways. Type IV is used where one of the through lanes, the outer lane, is reduced and another full width parallel from tangent lane developed with a taper is also forced to exit.
Prior Condition: No Prior Condition(s)
Category: Interchange design
Study: Safety Evaluation of Truck-Related Crashes at Freeway Diverge Areas, Zhenyu Wang, Bin Cao, Weiping Deng, Jian John Lu, and Zhao Zhang, 2011
| Star Quality Rating: |  [View score details] |
| Rating Points Total: | 95 |
| Crash Modification Factor (CMF) | |
|---|---|
| Value: | 1 |
| Adjusted Standard Error: | |
| Unadjusted Standard Error: | 0.15 |
| Crash Reduction Factor (CRF) | |
|---|---|
| Value: | 0 (This value indicates a decrease in crashes) |
| Adjusted Standard Error: | |
| Unadjusted Standard Error: | 15 |
| Applicability | |
|---|---|
| Crash Type: | Truck related |
| Crash Severity: | All |
| Roadway Types: | Principal Arterial Other Freeways and Expressways |
| 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: | Divided by Median |
| Minimum Speed Limit: | |
| Maximum Speed Limit: | |
| Speed Unit: | |
| Speed Limit Comment: | |
| Area Type: | Not specified |
| Traffic Volume: | |
| Average Traffic Volume: | |
| 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: | 2005 to 2008 |
| Municipality: | |
| State: | FL |
| Country: | usa |
| Type of Methodology Used: | Regression cross-section |
| Sample Size (crashes): | 4630 crashes |
| Other Details | |
|---|---|
| Included in Highway Safety Manual? | No |
| Date Added to Clearinghouse: | Jul 15, 2011 |
| Comments: | |
