Assessment of Pre-Preemption Strategy of Traffic Signals near Railroad Grade Crossing Utilizing Simulation Analysis

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Conference Proceeding

Publication Date



The current railroad crossing preemptions consider only safety issues involving train-vehicle crashes and allow the abbreviation of the vehicular minimum green time and shortening/omitting of the pedestrian “WALK” and flashing “DO NOT WALK” intervals. A few strategies in advance of the preemption were applied in previous studies to avoid the minimum green time abbreviations, as well as to improve mobility performance. However, those studies require the installation of infrastructure point detectors to predict train arrival and also provide extra green times for the non-dwell phases without considering the actual delays. This paper proposes to detect train arrival by utilizing the preemption activations and deactivations at the upstream intersections along the train’s path. Such a strategy is particularly feasible if a central signal control software can receive the notices of preemption activations and deactivations from the local controllers. Based on this type of train detection technology, the feasibility of various pre-preemption strategies was investigated in this paper using simulation analyses. Four out of thirteen pre-preemption strategies avoided minimum green time abbreviation in the tested scenarios. The Improved Transition Preemption Strategy (ITPS) was found to perform the best in terms of reducing average intersection delays.

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Citation / Publisher Attribution

TRB 93rd Annual Meeting, Compendium of Papers, Transportation Research Board, Washington, D.C., January 12-16, 2014.