Study Details

Study Title: Crash Modification Factors for High-Friction Surface Treatment in Pennsylvania

Authors: Gayah et al.

Publication Date:JUN, 2023

Abstract: The objective of this project was to develop a suite of crash modification factors (CMFs) to quantify the safety impacts of installing high-friction surface treatments (HFSTs) on horizontal curves and intersections within the Commonwealth of Pennsylvania. An empirical Bayes observational before-after study was performed to develop CMFs for this countermeasure. The propensity score matching framework was also used to identify an appropriate reference group of horizontal curves as comparison sites. CMFs were estimated for horizontal curves on two-lane rural roads, and the analysis found that HFST was associated with a statistically significant reduction in crash frequency of between 30% and 76% for all crash types considered. At intersections, HFST was associated with a statistically significant reduction in crash frequency of between 66% and 76%. The results are in line with engineering expectation, as HFST provides additional friction on the roadway surface that can help drivers maintain control.

Study Citation: Gayah, V., E.T. Donnell, and P. Zhang. "Crash Modification Factors for High-Friction Surface Treatment in Pennsylvania" Report No. PennDOT-2023-ECMS-E04834-WO15. The Pennsylvania Department of Transportation. Harrisburg, Pennsylvania. (June 2023).


CMFs Associated With This Study

Category: Roadway

Countermeasure: Install high friction surface treatment (HFST)

CMF CRF(%)QualityCrash TypeCrash SeverityRoadway TypeArea Type
0.46653.45 StarsAllAllNot specifiedRural
0.51348.75 StarsAllK,A,B,CNot specifiedRural
0.51448.65 StarsAllONot specifiedRural
0.47752.35 StarsRun off roadAllNot specifiedRural
0.49150.95 StarsFixed objectAllNot specifiedRural
0.27372.75 StarsAllAllNot specifiedRural
0.36863.24 StarsHead onAllNot specifiedRural
0.50649.44 StarsSideswipeAllNot specifiedRural
0.56445 StarsRun off roadK,A,B,CNot specifiedRural
0.58425 StarsFixed objectK,A,B,CNot specifiedRural
0.33266.84 StarsAllK,A,B,CNot specifiedRural
0.31694 StarsHead onK,A,B,CNot specifiedRural
0.33466.63 StarsAllAllNot specifiedAll
0.23476.62 StarsAllK,A,B,CNot specifiedAll
0.42255.85 StarsAllAllNot specifiedAll
0.52247.85 StarsAllK,A,B,CNot specifiedAll
0.41758.35 StarsAllONot specifiedAll
0.45754.35 StarsRun off roadAllNot specifiedAll
0.47752.35 StarsFixed objectAllNot specifiedAll
0.24475.65 StarsAllAllNot specifiedAll
0.50149.94 StarsHead onAllNot specifiedAll
0.7304 StarsSideswipeAllNot specifiedAll
0.64935.15 StarsRun off roadK,A,B,CNot specifiedAll
0.67232.85 StarsFixed objectK,A,B,CNot specifiedAll
0.32667.45 StarsAllK,A,B,CNot specifiedAll
0.44455.65 StarsAllAllNot specifiedAll
0.5505 StarsAllK,A,B,CNot specifiedAll
0.45554.55 StarsAllONot specifiedAll
0.4585 StarsRun off roadAllNot specifiedAll
0.47535 StarsFixed objectAllNot specifiedAll
0.24675.45 StarsAllAllNot specifiedAll
0.49514 StarsHead onAllNot specifiedAll
0.46753.34 StarsSideswipeAllNot specifiedAll
0.58441.65 StarsRun off roadK,A,B,CNot specifiedAll
0.6405 StarsFixed objectK,A,B,CNot specifiedAll
0.29870.25 StarsAllK,A,B,CNot specifiedAll
0.53946.14 StarsHead onK,A,B,CNot specifiedAll
0.67332.74 StarsSideswipeK,A,B,CNot specifiedAll
0.38861.25 StarsAllAllNot specifiedUrban
0.49650.45 StarsAllK,A,B,CNot specifiedUrban
0.36663.45 StarsAllONot specifiedUrban
0.45754.35 StarsRun off roadAllNot specifiedUrban
0.46253.85 StarsFixed objectAllNot specifiedUrban
0.22277.85 StarsAllAllNot specifiedUrban
0.53446.64 StarsHead onAllNot specifiedUrban
0.66733.34 StarsSideswipeAllNot specifiedUrban
0.69230.84 StarsRun off roadK,A,B,CNot specifiedUrban
0.71528.54 StarsFixed objectK,A,B,CNot specifiedUrban
0.32467.64 StarsAllK,A,B,CNot specifiedUrban
0.47852.25 StarsAllAllNot specifiedRural
0.56343.75 StarsAllK,A,B,CNot specifiedRural
0.50649.45 StarsAllONot specifiedRural
0.45754.35 StarsRun off roadAllNot specifiedRural
0.49650.45 StarsFixed objectAllNot specifiedRural
0.27972.15 StarsAllAllNot specifiedRural
0.40959.14 StarsHead onAllNot specifiedRural
0.77622.44 StarsSideswipeAllNot specifiedRural
0.60339.74 StarsRun off roadK,A,B,CNot specifiedRural
0.62637.44 StarsFixed objectK,A,B,CNot specifiedRural
0.32767.34 StarsAllK,A,B,CNot specifiedRural
0.43156.95 StarsAllAllNot specifiedUrban
0.4925 StarsAllK,A,B,CNot specifiedUrban
0.42557.55 StarsAllONot specifiedUrban
0.44555.55 StarsRun off roadAllNot specifiedUrban
0.45654.45 StarsFixed objectAllNot specifiedUrban
0.23276.85 StarsAllAllNot specifiedUrban
0.52447.64 StarsHead onAllNot specifiedUrban
0.45354.74 StarsSideswipeAllNot specifiedUrban
0.6035 StarsRun off roadK,A,B,CNot specifiedUrban
0.61638.45 StarsFixed objectK,A,B,CNot specifiedUrban
0.28725 StarsAllK,A,B,CNot specifiedUrban
0.61738.34 StarsHead onK,A,B,CNot specifiedUrban
0.68331.74 StarsSideswipeK,A,B,CNot specifiedUrban