Track Clearance Performance Measures for Railroad-Preempted Intersections

Track clearance green phases are used at railroad-preempted intersections to provide time to clear the railroad tracks of highway vehicles before a train arrives. This paper outlines performance measures based on high-resolution, real-time traffic signal event data that can be used to assess the maximum right-of-way transfer time to track clearance green phases as well as the synchronization of the track clearance phase with the railroad gate warning system located at the crossing. These performance measures were applied to a railroad-preempted intersection over a 13-month period. Right-of-way transfer times from more than 5,002 preemption events demonstrate the importance of using automated methods for validating design assumptions for right-of-way transfer time made by traffic engineers. Track clearance performance measures tabulated over 7,648 preemptions demonstrate the need for using a longer fixed, worst-case green time for track clearance or an extensible track clearance interval that terminates when the gates descend. The parameter description on how to get gate descent information can be inferred from either the active warning-time (flashing-light signals) activation or a separate gate-down circuit. The paper concludes with recommendations for incorporating these performance measures in traffic controller firmware to address recommendations proposed in 1996 by the National Transportation Safety Board after the Fox River Grove, Illinois, railroad–grade crossing crash in 1995.


  • English

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  • Accession Number: 01152865
  • Record Type: Publication
  • ISBN: 9780309160674
  • Report/Paper Numbers: 10-0118
  • Files: TRIS, TRB, ATRI
  • Created Date: Jan 25 2010 10:07AM