CMF / CRF Details
CMF ID: 4212
Increase all red clearance interval
Description: The average increase in the all red time was 1.1 seconds (minimum of 1.0 second and maximum of 2.0 seconds).
Prior Condition: Signalized intersection with yellow interval and most sites did not have an all red interval. The average increase in the all red time was 1.1 seconds (minimum of 1.0 second and maximum of 2.0 seconds).
Category: Intersection traffic control
Study: Evaluation of Safety Strategies at Signalized Intersections, Srinivasan, et al., 2011
| Star Quality Rating: |  [View score details] |
| Rating Points Total: | 90 |
| Crash Modification Factor (CMF) | |
|---|---|
| Value: | 0.863 |
| Adjusted Standard Error: | |
| Unadjusted Standard Error: | 0.114 |
| Crash Reduction Factor (CRF) | |
|---|---|
| Value: | 13.7 (This value indicates a decrease in crashes) |
| Adjusted Standard Error: | |
| Unadjusted Standard Error: | 11.4 |
| Applicability | |
|---|---|
| Crash Type: | All |
| Crash Severity: | K (fatal),A (serious injury),B (minor injury),C (possible injury) |
| Roadway Types: | Not Specified |
| 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: | Urban |
| Traffic Volume: | |
| Average Traffic Volume: | |
| Time of Day: | All |
| If countermeasure is intersection-based | |
| Intersection Type: | Roadway/roadway (not interchange related) |
| Intersection Geometry: | 3-leg,4-leg |
| Traffic Control: | Signalized |
| Major Road Traffic Volume: | Minimum of 5950 to Maximum of 31600 Annual Average Daily Traffic (AADT) |
| Minor Road Traffic Volume: | Minimum of 2650 to Maximum of 20225 Annual Average Daily Traffic (AADT) |
| Average Major Road Volume : | 17417 Annual Average Daily Traffic (AADT) |
| Average Minor Road Volume : | 8484 Annual Average Daily Traffic (AADT) |
| Development Details | |
|---|---|
| Date Range of Data Used: | 1992 to 2002 |
| Municipality: | San Diego, San Francisco, Howard County, and Montgomery County |
| State: | CA,MD |
| Country: | USA |
| Type of Methodology Used: | Before/after using empirical Bayes or full Bayes |
| Sample Size (sites): | 14 sites after |
| Other Details | |
|---|---|
| Included in Highway Safety Manual? | No |
| Date Added to Clearinghouse: | Dec 06, 2012 |
| Comments: | Assumed 2 crashes per site for both the before and after periods to estimate sample size. |
