Bayesian Methodology Incorporating Highway Safety Manual for Fitting and Updating Safety Performance Functions

In road safety studies, one often must cope with limited data conditions in the decision making process. In these circumstances, the maximum likelihood estimation―which relies on asymptotic theory―is not efficient. Besides, it has been reported in the literature that (a) Bayesian estimates might be significantly biased on account of using non-informative prior distributions and (b) the calibration of limited data is plausible when existing evidence in the form of proper priors is introduced into analyses. However, the road safety literature lacks a methodological approach to overcome the aforementioned problem. The authors present a method to estimate and/or update Safety Performance Function (SPF) parameters combining the information available from limited data with the SPF parameters values reported in the Highway Safety Manual (1). This method contributes to unification of the SPF parameters updating process. The proposed technique is validated by conducting a sensitivity analysis through an extensive simulation study with 15 different models (with various prior combinations), which in turn contributes to the understanding of the comparative aspects of a large number of prior distributions. The results evince the accuracy of the developed methodology. Therefore, the suggested approach offers considerable promise as a methodological tool to estimate and/or update baseline SPFs under limited data conditions.

• Supplemental Notes:
  • This paper was sponsored by TRB committee ANB25 Highway Safety Performance.
• Corporate Authors:

  Transportation Research Board

  500 Fifth Street, NW
  Washington, DC  United States  20001
• Authors:
  • Heydari, Shahram
  • Miranda-Moreno, Luis Fernando
  • Lord, Dominique
  • Fu, Liping
• Conference:
  • Transportation Research Board 93rd Annual Meeting
  • Location: Washington DC
  • Date: 2014-1-12 to 2014-1-16
• Date: 2014

Language

• English

Media Info

• Media Type: Digital/other
• Features: Figures; References; Tables;
• Pagination: 17p
• Monograph Title: TRB 93rd Annual Meeting Compendium of Papers

Subject/Index Terms

• TRT Terms: Bayes' theorem; Decision making; Highway safety; Sensitivity analysis; Simulation
• Identifier Terms: Highway Safety Manual
• Uncontrolled Terms: Safety performance functions
• Subject Areas: Highways; Planning and Forecasting; Safety and Human Factors; I72: Traffic and Transport Planning; I83: Accidents and the Human Factor;

Filing Info

• Accession Number: 01519613
• Record Type: Publication
• Report/Paper Numbers: 14-1519
• Files: TRIS, TRB, ATRI
• Created Date: Mar 26 2014 10:07AM