CMF / CRF Details
Install a combination of chevron signs, curve warning signs, and/or sequential flashing beacons
Countermeasure ID: 1870
Description: Along a curve with a small radius, large deflection angle, available sight distance smaller than stopping sight distance, and superelevation smaller than demanded at design and operating speed
Prior Condition: No curve delineation treatment. Radius is less than 300 m.
Category: Signs
Study: Safety Evaluation of Curve Delineation Improvements An Empirical Bayes Observational Before-After Study, Montella, 2009
| Crash Modification Factor (CMF) |
|---|
| Value: | 1.023 |
| Adjusted Standard Error: | |
| Unadjusted Standard Error: | 0.24 |
| Crash Reduction Factor (CRF) |
|---|
| Value: | -2.3 (This value indicates an increase in crashes) |
| Adjusted Standard Error: | |
| Unadjusted Standard Error: | 24 |
| Applicability |
|---|
| Crash Type: | Nighttime |
| Crash Severity: | All |
| Roadway Types: | Principal Arterial Other Freeways and Expressways |
| 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: | Not specified |
| Traffic Volume: | Minimum of 7400 to Maximum of 13975 Annual Average Daily Traffic (AADT) |
| Average Traffic Volume: | |
| Time of Day: | Night |
| 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: | 2001 to 2005 |
| Municipality: | Trans European Road Network, Italy |
| State: | notusa |
| Country: | |
| Type of Methodology Used: | Before/after using empirical Bayes or full Bayes |
| Sample Size (sites): | 10 sites after |
| Other Details |
|---|
| Included in Highway Safety Manual? | No |
| Date Added to Clearinghouse: | Dec 01, 2009 |
| Comments: | |
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