Study Details

Study Title: Quantifying the Safety Benefits of Transit Signal Priority Using Full Bayes Before–After Study

Authors: Ali et al.

Publication Date: 2022

Abstract: Transit signal priority (TSP) is a strategy that prioritizes the movement of transit vehicles through a signalized intersection to minimize transit delay and improve travel time reliability. Although the operational benefits are usually considered the primary criteria when deploying TSP, little attention is given to the anticipated safety impacts of TSP. Few studies that examined the safety impacts of TSP indicated inconsistent results. The objective of this study was to evaluate the safety performance of TSP. An observational before-after full Bayesian with a comparison-group approach was adopted to develop crash modification factors for total, fatal and injury (FI), and property damage only (PDO) crashes. The analysis was based on 41 transit corridors in Florida. Deployment of TSP resulted in a 12%, 14%, and 18% reduction in total, FI, and PDO crashes, respectively. Overall, the study results indicate that the deployment of TSP improves safety along the corridors. The study findings provide researchers and practitioners with an effective means for quantifying the safety benefits of the TSP and conducting an economic appraisal of TSP.

Study Citation: Ali, MD. S., A.E. Kitali, J. Kodi, P. Alluri, and T. Sando. "Quantifying the Safety Benefits of Transit Signal Priority Using Full Bayes Before–After Study". Journal of Transportation Engineers, Part A: Systems, Vol. 148 (1): 04021102, (2022).

Study Report: Download the Study Report Document


CMFs Associated With This Study

Category: Transit

Countermeasure: Implement transit signal priority

CMF CRF(%)QualityCrash TypeCrash SeverityRoadway TypeArea Type
0.88124 StarsAllAllAllUrban and suburban
0.86144 StarsAllK,A,B,CAllUrban and suburban
0.9284 StarsAllOAllUrban and suburban