Modelling the Performance of Signalized Intersections Near Railway Crossings

Inhi Kim,Luis Ferreira,Khaled Shaaban

doi:10.15344/2456-4451/2017/124

Abstract

Railway related pre-emption time, which refers to the time needed to clear a vehicle from the pathway of a train, isa necessary input for appropriate pre-emption traffic signal settings. It is, however, usually left to the judgment of the signal engineer, using assumptions not always based on hard evidence. The research reported here analysed the safety and performance at railway crossings in the vicinity of signalized intersections with the aid of micro traffic simulation modelling. The developed model was calibrated by comparing the time that the last vehicle on the railway tracks to be cleared. A location in Brisbane, Australia, was chosen to apply the proposed methodology. The case study was used to evaluate three settings, which were implemented using fixed signal time; pre-emption with actuated signal; and actuated signal only. The signal logic was developed with the aid of an external signal controller to replicate pre-emption technology. The resultsfrom the simulation model show that the use of the pre-emption benefits safety and driving performance by changing signals dynamically in accordance withconditions related to traffic flow, train frequency and the proportion of heavy goods vehicles.

Highlights

Railway signal pre-emption is intended to improve safety at road– railway intersections by minimizing the likelihood that a vehicle will become trapped at the crossing
The pre-emption of traffic signals at intersections near railway crossings induces traffic queues at the intersection not to extend over the railway crossing
Many researchers and practitioners have provided guidelines to ensure a better understanding of what is happening where traffic intersections and railway crossings are located in close proximity

Summary

Introduction

Railway signal pre-emption is intended to improve safety at road– railway intersections by minimizing the likelihood that a vehicle will become trapped at the crossing. When a train passes the crossing, vehicles on the road may be queued towards and away fromthe intersection. This paper addressesthe potentially dangerous conditions caused by a traffic queue backing up over an adjacent traffic control device located downstream from the crossing. Vehicles may become trapped at the crossing when the warning system is initially activated. The pre-emption of traffic signals at intersections near railway crossings induces traffic queues at the intersection not to extend over the railway crossing. In this way, vehicles do not block the train on the tracks [1]

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