CMF / CRF Details
Increase yellow change interval
Countermeasure ID: 4209
Description:
Prior Condition: Signalized intersection with yellow interval and most sites had an all red interval. The increase in yellow time was 1.0 second in all the sites.
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: | 0.934 |
| Adjusted Standard Error: | |
| Unadjusted Standard Error: | 0.237 |
| Crash Reduction Factor (CRF) | |
|---|---|
| Value: | 6.6 (This value indicates a decrease in crashes) |
| Adjusted Standard Error: | |
| Unadjusted Standard Error: | 23.7 |
| Applicability | |
|---|---|
| Crash Type: | Rear end |
| Crash Severity: | All |
| 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): | 5 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. |
