CMF / CRF Details
Implement transit signal priority
Countermeasure ID: 9819
Description: Transit signal priority (TSP) is a type of transit preferential treatment implemented at signalized intersections to reduce (bus or urban rail) transit delays by providing extended or early green time 3 to transit vehicles in operation.
Prior Condition: No TSP
Category: Transit
Study: Assessing Effects of Transit Signal Priority on Traffic Safety: Empirical Bayes Before-After Study Using King County, Washington Data, Song and Noyce, 2018
| Crash Modification Factor (CMF) |
|---|
| Value: | 0.841 |
| Adjusted Standard Error: | |
| Unadjusted Standard Error: | 0.021 |
| Crash Reduction Factor (CRF) |
|---|
| Value: | 15.9 (This value indicates a decrease in crashes) |
| Adjusted Standard Error: | |
| Unadjusted Standard Error: | 2.1 |
| Applicability |
|---|
| Crash Type: | All |
| Crash Severity: | O (property damage only) |
| 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: | Not specified |
| If countermeasure is intersection-based |
| Intersection Type: | Roadway/railroad grade crossing |
| Intersection Geometry: | No values chosen. |
| Traffic Control: | Signalized |
| Major Road Traffic Volume: | Minimum of 7268 to Maximum of 44576 Annual Average Daily Traffic (AADT) |
| Minor Road Traffic Volume: | |
| Average Major Road Volume : | 26705 Annual Average Daily Traffic (AADT) |
| Average Minor Road Volume : | |
| Development Details |
|---|
| Date Range of Data Used: | 2002 to 2015 |
| Municipality: | King County |
| State: | WA |
| Country: | USA |
| Type of Methodology Used: | Before/after using empirical Bayes or full Bayes |
| Sample Size (crashes): | 2304 crashes after |
| Sample Size (sites): | 11 sites before, 11 sites after |
| Other Details |
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| Included in Highway Safety Manual? | No |
| Date Added to Clearinghouse: | Oct 27, 2018 |
| Comments: | |
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