SHORT-TERM, WEATHER-RELATED SKID RESISTANCE VARIATIONS

A three-year research program was initiated in 1978 at the Pennsylvania Transportation Institute by the U.S. Department of Transportation to investigate possible causes for seasonal and short-term skid resistance variations. The primary objective is to determine the parameters that can be used to predict the influence of seasonal and short-term effects. Results concerning short-term, weather-related skid resistance variations are presented and discussed. Twenty-one test surfaces in State College, Pennsylvania, were selected for testing. The testing program includes daily skid measurements according to ASTM test method E274 and the collection of daily weather data. After the data are adjusted for long-term variations, the short-term residuals are regressed against rainfall and temperature parameters. The number of days since the last significant rainfall and the test pavement temperature are both found to be significant causes of short-term skid resistance variations. Further unexplained variations are attributable to measurement errors, particularly the lateral placement of the skid test trailer. The Pennsylvania results are supported by data collected in a similar study of 10 sites located in North Carolina and Tennessee (Federal Highway Administration Region 15). (Authors)