CMF / CRF Details
CMF ID: 3900
Provide an auxiliary lane between an entrance ramp and exit ramp
Description:
Provide an auxiliary lane between an entrance ramp and exit ramp
Prior Condition: directional freeway segment containing a combination of an entrance ramp and an exit ramp without an auxiliary lane between the entrance ramp and exit ramp
Category: Interchange design
| Crash Modification Factor (CMF) |
|---|
| Value: | 0.8 |
| Adjusted Standard Error: | |
| Unadjusted Standard Error: | |
| Crash Reduction Factor (CRF) |
|---|
| Value: | 20 (This value indicates a decrease in crashes) |
| Adjusted Standard Error: | |
| Unadjusted Standard Error: | |
| Applicability |
|---|
| Crash Type: | Single vehicle |
| 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 15928 to Maximum of 104079 Average Daily Traffic (ADT) |
| Minor Road Traffic Volume: | Minimum of 84 to Maximum of 31495 Average Daily Traffic (ADT) |
| Average Major Road Volume : | 41644 Average Daily Traffic (ADT) |
| Average Minor Road Volume : | 5763 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): | 1814 crashes |
| Other Details |
|---|
| Included in Highway Safety Manual? | No |
| Date Added to Clearinghouse: | Jun 04, 2012 |
| Comments: | This CMF was obtained from Exhibit 3-35 for the variable AuxLn for single vehicle crashes: e^(-0.2241)= 0.80 The analysis is based on one direction of travel. The sample size was computed from Exhibit 3-33 as 11.7 crashes per segment * 155 segments = 1,814 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 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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