Since its first use in the 1960s, the locked-wheel skid testers have used the ribbed (ASTM E501) rather than the smooth (ASTM E524) tire. The early history of the ASTM E274 locked-wheel testers is discussed, and reasons the ribbed tire was originally the standard tireare explained. The use of smooth versus ribbed tires is also examined. First the effect of film thickness on the two tires is reviewed;then the use of each or both tires is discussed in the evaluation of accident data. Finally, the relationship of skid measurement usingone or both tires with texture is reviewed. It is concluded that both current research and current use would recommend that the use of both tires produces the best data; however, if a single tire is to be used, then the smooth tire would be recommended because it gives more-useful data than the ribbed tire
Abstract