CMF / CRF Details
CMF ID: 3922
Change the inverse of the ramp spacing from X to Y (1/feet)
Description:
Change the inverse of the distance between the gore of one ramp and the gore of the other ramp from X to Y (1/feet)
Prior Condition: directional freeway segment containing two entrance ramps where the spacing between the merging tips is 1/X feet
Category: Interchange design
| Crash Modification Factor (CMF) |
|---|
| Value: | .bmp) |
| Adjusted Standard Error: | |
| Unadjusted Standard Error: | |
| Crash Reduction Factor (CRF) |
|---|
| Value: | .bmp) |
| Adjusted Standard Error: | |
| Unadjusted Standard Error: | |
| Applicability |
|---|
| Crash Type: | All |
| 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: | Not specified |
| Traffic Volume: | |
| Average Traffic Volume: | |
| Time of Day: | All |
| If countermeasure is intersection-based |
| Intersection Type: | Roadway/roadway (interchange ramp terminal) |
| Intersection Geometry: | |
| Traffic Control: | |
| Major Road Traffic Volume: | Minimum of 3459 to Maximum of 99030 Average Daily Traffic (ADT) |
| Minor Road Traffic Volume: | Minimum of 208 to Maximum of 27570 Average Daily Traffic (ADT) |
| Average Major Road Volume : | 42254 Average Daily Traffic (ADT) |
| Average Minor Road Volume : | 7564 Average Daily Traffic (ADT) |
| Development Details |
|---|
| Date Range of Data Used: | 2005 to 2007 |
| Municipality: | |
| State: | WA |
| Country: | U.S.A. |
| Type of Methodology Used: | Regression cross-section |
| Sample Size (crashes): | 864 crashes |
| Other Details |
|---|
| Included in Highway Safety Manual? | No |
| Date Added to Clearinghouse: | Jun 04, 2012 |
| Comments: | This CMF was obtained from Exhibit 3-36 for the variable S^-1 for total crashes. The analysis is based on one direction of travel. The sample size was computed from Exhibit 3-34 as 28.8 crashes per segment * 30 segments = 864 crashes. The sites are comprised of multiple roadway types, primarily of interstates and freeways but also of routes with lower functional classifications (p. 3-45). Interchange-related is not available so intersection-related was selected. The traffic volumes were obtained from Exhibit 3-31. The minimum minor traffic volume was the lesser of the entrance and exit minimum ADTs. Similarly, the maximum minor traffic volumes was the greater of the entrance and exit maximum ADTs. The average minor traffic volume was computed as the average of the averages. |
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