Download or read book Developing Crash-Modification Factors for High Friction Surface Treatments written by David K. Merritt and published by . This book was released on 2020 with total page 75 pages. Available in PDF, EPUB and Kindle. Book excerpt: This report documents results and observations from friction testing of high-friction surface treatments (HFSTs) as part of an FHWA research study, Developing Crash-Modification Factors for High-Friction Surface Treatments. This larger study provides high-quality crash-modification factors and benefit–cost ratios for HFST with calcined bauxite aggregate and recommends materials and specifications for applying HFST to effectively reduce roadway departure crashes. Friction testing was performed to document the friction of the HFST and underlying pavement. For a number of sites, friction testing was performed on the existing pavement surface before HFST installation and on the HFST after installation. In some cases, testing of the pavement leading up to and away from existing HFST sites was used to estimate the friction of the underlying pavement for comparison to HFST friction. To evaluate friction change of HFST over time, friction testing was also performed on several older HFST installations where previous friction data had been collected. All friction testing was performed with a highway friction tester, a continuous fixed-slip measurement device that provides a continuous plot of friction reported in 0.30-meter (1-foot) increments through the section of pavement tested. The advantage of continuous friction measurement is that variations in friction (e.g., through a curve) can be documented. 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 within a curve.