Crash Reduction Analysis of Friction Improvement Surface Treatments in Georgia

Crashes on curves represent 25 % of all roadway fatalities the vast majority of these fatalities are roadway departures. An effective treatment to mitigate roadway departures are friction improvement surface treatments (FISTs). The Georgia Department of Transportation (GDOT) has implemented friction improvements on more than 400 curves. Before this study, there were no crash modification factors (CMFs) for these friction improvements in Georgia. Thus, the objective of this study was to analyze the crash reduction effectiveness of three FISTs in Georgia. These materials include phonolite, lightweight aggregate (LWA), and high friction surface treatment (HFST, or calcined bauxite). This objective was achieved by using naïve Bayes and empirical Bayes methods to develop CMFs. The calculated CMFs show that HFST significantly reduces curve crashes with an overall CMF of 0.672. HFST is the only material implemented where the calculated CMFs provided significant evidence for crash reduction. Crash types that were significantly reduced include single vehicle, those labeled as negotiating a curve, and wet road. The CMF was then modeled as a function of the roadway environment. It was found that significant curve site characteristics that led to a lower (i.e., more effective) CMF were 1) prior crash frequency, 2) absence of an intersection, and 3) lower traffic volumes. These findings are used to display CMFs for different site characteristics and can be used to strategize implementation of HFST on curves in the future. It is recommended to perform life cycle cost-integrated crash reduction benefit cost analyses.


  • English

Media Info

  • Media Type: Digital/other
  • Features: Figures; Maps; References; Tables;
  • Pagination: 22p

Subject/Index Terms

Filing Info

  • Accession Number: 01874555
  • Record Type: Publication
  • Report/Paper Numbers: TRBAM-23-02971
  • Files: TRIS, TRB, ATRI
  • Created Date: Feb 24 2023 9:05AM