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Roadway departure (RwD) and intersection crashes make up 75 percent of all traffic fatalities in the U.S. and many of those crashes can be prevented if adequate pavement friction is available to meet friction demand. In Kentucky, 60-70% of their yearly highway fatalities are the result of...
This Primer was developed to serve as a resource for road safety, maintenance, materials, and pavement engineers and practitioners to provide a basic understanding of pavement surface friction in order to integrate pavement friction into both pavement asset management and road safety...
This report documents the development of safety performance functions (SPFs) that include friction and macrotexture on a variety of roadway facility types and categories (i.e., segments, intersections, curves, and ramps). The main objectives of the report were: (1) the development of Crash...
ATSSA, Safety Opportunities in High Friction Surfacing, American Traffic Safety Services Association, February 2013.
Federal Highway Administration, Horizontal Curve Safety, U.S. Department of Transportation, Washington, DC, February 2012, available at: http://www-nrd.nhtsa.dot.gov/Pubs/811552.pdf.
This section of the document provides some specific examples where an HFST was placed to reduce wet-weather roadway departures and crashes. A total of four projects are included in this section.
Location 1: Madison County, Kentucky; KY-21, MP 6.7-6.9 Installation: November 2010 |
As noted above, HFST is a spot treatment that is applied to an existing roadway surface that increases the surface friction characteristics, allowing for better traction. This application consists of a binder resin system combined with polish- and abrasion-resistant aggregates. Different aggregate and binder resin system materials are available to use when applying an HFST. The following paragraphs briefly identify and explain the contracting process that was used and the materials selected for use by KYTC.
This section discusses the data collection and analysis used for site selection and monitoring after HFST placement to assess the impact on crashes and HFST friction characteristics.
As mentioned in section 3.2, the initial selection of two high-crash locations with high friction demand served Kentucky well in launching their HFST program. The significant after treatment crash reductions were realized immediately, which led to the selection of additional sites to more clearly prove the benefit. To develop an effective HFST program, however, KYTC needed a process to screen for the most appropriate locations to be treated. This section describes the evolution of KYTC's site selection screening processes.
Kentucky, the FHWA, and other agencies have reported significant crash reductions at a number of high-crash sites where an HFST was applied and monitored. While HFST is yet to be known or understood by many practitioners in the United States, that should change in the future with the increased awareness and publicity of Kentucky's successful program. In addition, the American Traffic Safety Services Association (ATSSA) is undertaking an effort to promote a better understanding of the benefits of HFSTs.
HFSTs were originally developed in the United States during the 1950s using epoxy resin, but their use has increased in recent years. An HFST wearing surface has been successfully used in Europe and Asia for decades, including on a wide scale in London in the early 1970's. HFST wearing surface has also been tried and proven at a wide variety of sites as part of the FHWA's Surface Enhancements at Horizontal Curves (SEAHC) demonstration program.