The Who and Where of Road Safety: Extracting Surrogate Indicators from Smartphone-Collected GPS Data in Urban Environments

Environment and driver behavior are significant contributory factors in traffic collisions. Surrogate safety measures, non-crash measures that are physically and predictably related to crashes, provide opportunities for user-centric approaches to road safety and reduce dependency on crash data in location-centric approaches. The purpose of this study is to extract surrogate safety measures from the smartphone-collected GPS data of regular drivers and to analyze those measures from a location-centric and user-centric perspective. GPS travel data was collected using the Mon Trajet smartphone application in Quebec City, Canada over 21 days. Crash data was obtained from the Ministry of Transportation Quebec for a five year period from 2006 to 2010. The selected surrogate indicator, hard braking events (HBEs), demonstrated a spatial correlation of 0.67 with collision occurrence. Despite strong correlation, HBEs tend to overestimate risk on highway facilities and underestimate risk on local and arterial streets as the sample data collected from regular drivers likely over-represents travel on highways and under-represents travel on urban streets. The user-centric analysis showed that more HBEs occur during the AM and PM peak periods, and that braking in the PM peak period tends to be more severe, demonstrating that HBEs are not only spatially correlated with actual collision occurrence, but also make sense intuitively with respect to the behaviors related to collision occurrence. Future work will determine if other surrogate indicators that are more closely correlated with collision occurrence can be extracted, and disaggregating the analyses by facility type should improve the results.

  • Supplemental Notes:
    • This paper was sponsored by TRB committee ANB20 Standing Committee on Safety Data, Analysis and Evaluation.
  • Corporate Authors:

    Transportation Research Board

    500 Fifth Street, NW
    Washington, DC  United States  20001
  • Authors:
    • Stipancic, Joshua
    • Miranda-Moreno, Luis
    • Saunier, Nicolas
  • Conference:
  • Date: 2016


  • English

Media Info

  • Media Type: Web
  • Features: Figures; Maps; References; Tables;
  • Pagination: 15p
  • Monograph Title: TRB 95th Annual Meeting Compendium of Papers

Subject/Index Terms

Filing Info

  • Accession Number: 01590022
  • Record Type: Publication
  • Report/Paper Numbers: 16-2848
  • Files: TRIS, TRB, ATRI
  • Created Date: Feb 9 2016 9:18AM