In PennDOT's ongoing mission to reach the national highway safety goal of zero fatalities, the agency's use of the innovative High Friction Surface Treatment (HFST) is having a significant impact.
Beginning in 2007 with the first application on Pennsylvania Route 611 in Northampton County, High Friction Surface Treatment has been used more than 250 locations across the state.
PennDOT has seen impressive results.
PennDOT performed a crash data analysis of 47 locations and found that for an investment of just over $3 million, the return in reduced fatalities, injuries and property damage was more than $8.5 million.
"A safety countermeasure that results in significant crash reductions like HFST is excellent," said Jason Hershock, PennDOT's manager for safety engineering and risk management. "This innovation supports PennDOT's efforts to address safety on Pennsylvania highways."
Follow-up crash data analysis at 47 locations, where crash data was available for at least three to five years after HFST installation, showed a significant crash reduction in wet road, run-off-road, hit fixed object and all crashes. Fatalities at these locations went from eight to zero and injury crashes went from 190 to 71, a 63 percent decrease.
The difference ingredient-wise in HFST is the use of an epoxy binder and calcined bauxite aggregate, which is laid on top of the surface.
"The bauxite aggregates are small in size and contains mostly alumina content that results in higher friction compared to traditional pavement," Hershock noted.
Its use is based in part on crash analysis of curves and intersections, where there is a need to help drivers stay on the road and reduce stopping distances to avoid crashes due to running stop signs or traffic signals and avoiding rear end crashes.
A Federal Highway Administration (FHWA) Every Day Counts innovation, championed by the Pennsylvania State Transportation Innovation Council, this treatment can also help PennDOT deal with safety issues where there are unusual environmental challenges.
"High Friction Surface Treatment has been successfully used on a number of sites in District 8," said Mike Keiser, district executive for PennDOT Engineering District 8, which covers south central Pennsylvania. "In each case, crash rates have been decreased."
For example, in 2013, District 8 was looking for a safety upgrade on Route 147 in Halifax, where 90-year-old historic sycamore trees planted to commemorate World War I veterans were being hit by vehicles departing the roadway resulting in fatal crashes. Knowing the trees could not be removed and guiderail was not the best option, the district turned to High Friction Surface Treatment as well as other safety improvements. As a result, fatal crashes have been eliminated at this location to date.
"On rural, low-volume, roadways with higher speed limits, this treatment is a very viable alternative compared to an expensive long-term construction effort to modify the roadway alignment," noted Keiser.