Naznin Farhana, Currie Graham, Sarvi Majid, Logan David
a Institute of Transport Studies , Department of Civil Engineering , Monash University , Clayton , Victoria , Australia.
b Monash University Accident Research Centre , Monash University , Clayton , Victoria , Australia.
Traffic Inj Prev. 2016;17(1):91-7. doi: 10.1080/15389588.2015.1035369. Epub 2015 Apr 2.
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.
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.
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.
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.
有轨电车系统在全球范围内不断发展，许多系统被赋予优先权以提高在混合交通条件下的速度和可靠性。与有轨电车优先权对道路安全影响相关的研究有限。本研究探讨了有轨电车优先权措施（包括车道优先权和交叉路口/信号优先权措施）对道路安全的影响。
采用经验贝叶斯（EB）方法进行前后碰撞研究，通过考虑更广泛的碰撞趋势和均值回归效应，以提供更准确的碰撞影响估计。分析了澳大利亚墨尔本29个具有有轨电车信号优先权的交叉路口和23条具有有轨电车车道优先权的主干道的前后碰撞数据，以评估有轨电车优先权对道路安全的影响。
经验贝叶斯前后分析结果表明，实施有轨电车优先权措施后，经调整的碰撞减少率具有统计学意义，为16.4%。发现信号优先权措施使碰撞减少了13.9%，车道优先权使碰撞减少了19.4%。非汇总层面的简单前后分析表明，总碰撞和严重碰撞以及涉及车辆、行人及摩托车的碰撞均有所减少。此外，实施有轨电车优先权后，还发现路中碰撞、涉及行人的碰撞以及同向和反向行驶车辆之间的碰撞以及所有其他特定碰撞类型均有所减少。
结果表明，有轨电车/电车优先权措施为所有道路使用者（包括车辆、行人及骑自行车者）带来了安全益处。讨论了政策影响和未来研究领域。
