title: An empirical Bayes safety evaluation of tram/streetcar signal and lane priority measures in Melbourne.
abstract: OBJECTIVE
  Streetcars/tram systems are growing worldwide, and many are given priority to increase speed and reliability performance in mixed traffic conditions. Research related to the road safety impact of tram priority is limited. This study explores the road safety impacts of tram priority measures including lane and intersection/signal priority measures.
  
  
  METHODS
  A before-after crash study was conducted using the empirical Bayes (EB) method to provide more accurate crash impact estimates by accounting for wider crash trends and regression to the mean effects. Before-after crash data for 29 intersections with tram signal priority and 23 arterials with tram lane priority in Melbourne, Australia, were analyzed to evaluate the road safety impact of tram priority.
  
  
  RESULTS
  The EB before-after analysis results indicated a statistically significant adjusted crash reduction rate of 16.4% after implementation of tram priority measures. Signal priority measures were found to reduce crashes by 13.9% and lane priority by 19.4%. A disaggregate level simple before-after analysis indicated reductions in total and serious crashes as well as vehicle-, pedestrian-, and motorcycle-involved crashes. In addition, reductions in on-path crashes, pedestrian-involved crashes, and collisions among vehicles moving in the same and opposite directions and all other specific crash types were found after tram priority implementation.
  
  
  CONCLUSIONS
  Results suggest that streetcar/tram priority measures result in safety benefits for all road users, including vehicles, pedestrians, and cyclists. Policy implications and areas for future research are discussed.
authors.affiliation: a Institute of Transport Studies , Department of Civil Engineering , Monash University , Clayton , Victoria , Australia.
authors.forename: Farhana
authors.initials: F
authors.lastname: Naznin
authors.affiliation: a Institute of Transport Studies , Department of Civil Engineering , Monash University , Clayton , Victoria , Australia.
authors.forename: Graham
authors.initials: G
authors.lastname: Currie
authors.affiliation: a Institute of Transport Studies , Department of Civil Engineering , Monash University , Clayton , Victoria , Australia.
authors.forename: Majid
authors.initials: M
authors.lastname: Sarvi
authors.affiliation: b Monash University Accident Research Centre , Monash University , Clayton , Victoria , Australia.
authors.forename: David
authors.initials: D
authors.lastname: Logan
mesh_terms: D000063:Accidents, Traffic / Q000517:prevention & control* / Q000706:statistics & numerical data; D001315:Australia; D001499:Bayes Theorem; D006801:Humans; D018986:Motor Vehicles; D009049:Motorcycles; D000069636:Pedestrians; D015203:Reproducibility of Results; D012449:Safety
keywords: before–after study; crashes; empirical Bayes method; road safety; streetcar priority; tram priority