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Federal Highway Administration Research and Technology
Coordinating, Developing, and Delivering Highway Transportation Innovations

This report is an archived publication and may contain dated technical, contact, and link information
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Publication Number:  FHWA-HRT-20-061    Date:  September 2020
Publication Number: FHWA-HRT-20-061
Date: September 2020


Developing Crash-Modification Factors for High Friction Surface Treatments

PDF Version (4.03 MB)


The research documented in this report was conducted as part of the Federal Highway Administration's (FHWA's) Evaluation of Low-Cost Safety Improvements Pooled Fund Study (ELCSI-PFS). FHWA established this PFS in 2005 to research the effectiveness of the safety improvements identified by the National Cooperative Highway Research Program's Report 500 Series as part of the implementation of the American Association of State Highway and Transportation Officials' Strategic Highway Safety Plan. The ELCSI-PFS research studies provide a crash modification factor and benefit–cost economic analysis for each targeted safety strategy identified as a priority by the PFS member States.

This report provides high-quality CMFs and B/C ratios for high-friction surface treatments (HFSTs) with calcined bauxite aggregate and recommends materials and specifications for applications to effectively reduce roadway-departure crashes. This dat-driven study used before- and after-crash data to quantify crash-reduction benefits and used friction data collected by the research team before and after HFST installation to help quantify the impact of increased pavement friction on CMFs. The study collected data for HFST installations on curves and ramps in Arkansas, Georgia, Kentucky, Louisiana, Pennsylvania, and West Virginia. The results of this study indicate using HFSTs with calcined bauxite aggregate reduces roadway-departure crashes at curves and ramps, particularly for wet-weather crashes. This report is supplemented by FHWA-HRT-20-062, Developing Crash-Modification Factors for High-Friction Surface Treatments: Friction Change Report, and will benefit safety engineers and safety planners by providing greater insight into applications of HFSTs for improving highway safety.

Brian P. Cronin, P.E.
Director, Office of Safety and Operations
Research and Development


This document is disseminated under the sponsorship of the U.S. Department of Transportation (USDOT) in the interest of information exchange. The U.S. Government assumes no liability for the use of the information contained in this document.

The U.S. Government does not endorse products or manufacturers. Trademarks or manufacturers’ names appear in this report only because they are considered essential to the objective of the document.

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