Improving Crash Prediction - A More Relevant Exposure Measure than AADT for Highway-Rail Crossing Safety Models

The objective of this research is to improve Highway-Rail Grade Crossing (HRGC) crash prediction by developing a more relevant crash exposure term in place of annual average daily traffic (AADT) for use in HRGC safety models. HRGC safety models have been around in the United States since at least 1940s (e.g., Peabody-Dimmick Formula). Safety models are used for HRGC crash predictions and the results often used for allocation of safety resources ($) amongst HRGCs. A staple of these models is the annual average daily traffic (AADT), which is a measure of yearly motor vehicle roadway usage and serves as a crash exposure term in safety models. Crash exposure accounts for the state of being subjected to the likelihood of a crash; higher exposure implies higher likelihood of crashes. A more relevant measure of exposure at HRGCs is to consider only the portion of AADT that encounters train traffic, called (AADT)Encounter_Train in this research. This is theoretically more suitable because the exposure of motorists to train-involved crashes in the absence of trains is zero and consideration of the non-relevant portion of AADT (i.e., vehicular traffic at the HRGC when no trains are present) in safety models masks the true picture. This research will undertake the following: (1) Develop a taxonomy of different Nebraska HRGCs based on criteria such as presence of gates, flashing lights, number of crossing tracks, etc.; (2) For each group of HRGCs, estimate (AADT)Encounter_Train as well as estimate the roadway AADT; (3) Establish a relationship between (AADT)Encounter_Train and AADT for each group of HRGCs; and (4) Test the validity of using (AADT)Encounter_Train in place of AADT in HRGC safety models and assess differences in crash predictions using (AADT)Encounter_Train and AADT. This research is expected to improve the quality of crash predictions at HRGCs thereby improving public safety and aiding more informed resource allocation for HRGC safety improvements


  • English


  • Status: Active
  • Funding: $108375
  • Contract Numbers:


  • Sponsor Organizations:

    Nebraska Department of Roads

    1500 Highway 2
    Lincoln, Nebraska  United States  68509-4759

    Research and Innovative Technology Administration

    University Transportation Centers Program
    1200 New Jersey Avenue, SE
    Washington, DC  United States  20590
  • Managing Organizations:

    University of Nebraska, Lincoln

    1400 R Street
    Lincoln, NE  United States  68588
  • Performing Organizations:

    University of Nebraska, Lincoln

    1400 R Street
    Lincoln, NE  United States  68588
  • Principal Investigators:

    Khattak, Aemal

  • Start Date: 20161001
  • Expected Completion Date: 20180630
  • Actual Completion Date: 0
  • USDOT Program: University Transportation Centers
  • USDOT Program: University Transportation Centers Program

Subject/Index Terms

Filing Info

  • Accession Number: 01616220
  • Record Type: Research project
  • Source Agency: University Transportation Center for Railway Safety
  • Contract Numbers: DTRT13-G-UTC59
  • Files: UTC, RiP
  • Created Date: Nov 11 2016 11:51AM