U.S. Department of Transportation
Federal Highway Administration
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Washington, DC 20590
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Federal Highway Administration Research and Technology
Coordinating, Developing, and Delivering Highway Transportation Innovations
| REPORT |
| 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 |
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
Notice
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.
Quality Assurance Statement
The Federal Highway Administration (FHWA) provides high-quality information to serve Government, industry, and the public in a manner that promotes public understanding. Standards and policies are used to ensure and maximize the quality, objectivity, utility, and integrity of its information. FHWA periodically reviews quality issues and adjusts its programs and processes to ensure continuous quality improvement.
| 1. Report No. FHWA-HRT-20-061 |
2. Government Accession No. | 3. Recipient’s Catalog No. | ||||
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| 4. Title and Subtitle Developing Crash-Modification Factors for High Friction Surface Treatments |
5. Report Date September 2020 |
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| 6. Performing Organization Code | ||||||
| 7. Author(s) David K. Merritt, Craig A. Lyon, Bhagwant N. Persaud (ORCID: 0000-0002-8404-9236), and Helga N. Torres |
8. Performing Organization Report No. 110952.01.009 |
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| 9. Performing Organization Name and Address MRIGlobal VHB 8300 Boone Boulevard, Suite 700 Vienna, VA 22182 |
10. Work Unit No. (TRAIS) | |||||
| 11. Contract or Grant No. DTFH61-13-D-0001 |
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| 12. Sponsoring Agency Name and Address Office of Safety Research and Development Federal Highway Administration 6300 Georgetown Pike McLean, VA 22101–2296 |
13. Type of Report and Period Covered Final Report; December 2015–August 2019 |
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| 14. Sponsoring Agency Code HRDS-20 |
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| 15. Supplementary Notes This report was prepared for the Federal Highway Administration (FHWA) Office of Safety Research and Development under Contract DTFH61-13-D-0001. The FHWA program and task manager for this project was Roya Amjadi (HRDS-20; ORCID: 0000-0001-7672-8485). Andy Mergenmeier (DTS-RC-BAL-1; ORCID: 0000-0003-4837-6528) and Joseph Cheung (HAS-HSST) contributed to this study. |
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| 16. Abstract Over the past 10 to 15 yr, the use of high-friction surface treatments (HFSTs) as a safety countermeasure has grown exponentially. HFSTs are pavement-surface treatments that restore or enhance pavement friction at locations with high friction demand, such as curves, ramps, and intersection approaches. While the crash-reduction benefits of HFSTs have been observed by many State highway agencies, the availability of crash-modification factors (CMFs) for HFSTs is limited. This study provides high-quality and robust CMFs and benefit–cost ratios for HFSTs with calcined bauxite aggregate and recommends materials and specifications (as appropriate) for applications. This study also notes where and under what conditions to use HFSTs to effectively reduce roadway departure crashes. This study was data-driven and used before- and after-crash data to quantify crash reduction benefits. The study also used friction data collected by the research team before (when available) and after HFST installation to help quantify the impact of increased pavement friction on the CMFs. Data were collected for hundreds of HFST installations in Arkansas, Georgia, Kentucky, Louisiana, Pennsylvania, and West Virginia on curves and ramps. The results for curves and ramps indicate significant benefits in terms of low CMFs, particularly for wet-weather crashes. A thorough disaggregate analysis of the before–after evaluation data for curves suggested a logical and consistent relationship between CMFs and three variables: friction improvement, annual average daily traffic, and expected crash frequency before treatment. A complementary evaluation was conducted under this study for friction changes of HFSTs over time; the results are documented in FHWA-HRT-20-062, Developing Crash-Modification Factors for High-Friction Surface Treatments: Friction Change Report. Friction testing was performed on several older HFST installations where previous friction data were collected. All friction testing was performed with the Federal Highway Administration's highway friction tester, a continuous fixed-slip measurement device. The friction data collected during this research and documented in this report were evaluated for friction change before and after HFST installation, friction change of the HFST and existing pavement over time, and friction change through a curve. |
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| 17. Key Words High-friction surface treatment, crash-modification factor, benefit–cost ratio, friction testing |
18. Distribution Statement No restrictions. This document is available to the public through the National Technical Information Service, Springfield, VA 22161. http://www.ntis.gov |
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| 19. Security Classif. (of this report) Unclassified |
20. Security Classif. (of this page) Unclassified |
21. No. of Pages 84 |
22. Price N/A |
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| Form DOT F 1700.7 (8-72) | Reproduction of completed pages authorized. | |||||
