CMF / CRF Details
CMF ID: 2949
Increase in horizontal curvature from X to Y degrees (assuming 100 meter arc length)
Description:
For horizontal alignment increase degree of curvature from X to Y (degree of curvature defined as angle subtended by 100 meter arc not 100 ft arc)
Prior Condition: No Prior Condition(s)
Category: Alignment
| Crash Modification Factor (CMF) |
|---|
| Value: |  |
| Adjusted Standard Error: | |
| Unadjusted Standard Error: | |
| Crash Reduction Factor (CRF) |
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| Value: |  |
| Adjusted Standard Error: | |
| Unadjusted Standard Error: | |
| Applicability |
|---|
| Crash Type: | All |
| Crash Severity: | All |
| Roadway Types: | Not Specified |
| Street Type: | |
| Minimum Number of Lanes: | 4 |
| Maximum Number of Lanes: | 4 |
| 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: | Not specified |
| Intersection Geometry: | Not specified |
| Traffic Control: | Not specified |
| Major Road Traffic Volume: | |
| Minor Road Traffic Volume: | |
| Average Major Road Volume : | |
| Average Minor Road Volume : | |
| Development Details |
|---|
| Date Range of Data Used: | 2001 to 2002 |
| Municipality: | |
| State: | notusa |
| Country: | Korea |
| Type of Methodology Used: | Regression cross-section |
| Other Details |
|---|
| Included in Highway Safety Manual? | No |
| Date Added to Clearinghouse: | Mar 21, 2011 |
| Comments: | The authors make no mention of the traffic volumes on their sample of roads. They also state that highway segments were divided into 3 categories (divided, non-intersection, or intersection) while crashes were divided by type (pedestrian or vehicle) (p. 544). However, they don't specify how they dealt with these different categories. They also state that the "current" data are from 2002 and the "historical" data are from 2001 (p. 544). Table 3 includes 2003 data, and Table 4 excludes historical data. Since the zero-inflated regression models with the power prior use both current and historical data, the true sample sizes used for the models do not seem to be given in the paper. The method is a cross-sectional analysis, but employs Baysian techniques.Also, it should be noted that the degree of curvature in this paper assumes a 100 meter arc not a 100 foot arc as is customary in the US. |
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