Crash experience on tined and continuously ground portland cement concrete pavements

Crash rates were compared between 290 km of continuously ground and 115 km of transversely tined portland cement concrete pavements in Wisconsin. All 11,219 reported crashes at the study sites during the 6-year period 1988 through 1993 were analyzed. Continuously ground surfaces were found to have lower crash rates than tined surfaces under dry and wet conditions during daytime and nighttime as well as under all four combinations of pavement and light conditions. Ground pavements had 58 percent the crash rates of tined pavements under dry and wet conditions; the ratio was 84 percent when snow or ice was present on the pavement; however, relatively limited vehicular travel occurred under such conditions and these results are viewed as preliminary. Ground pavements had 57 percent the crash rates of tined pavements during daytime; the ratio was 73 percent at night. On the basis of the available data, a hypothesis of increasing crash rates with time (based on frictional property deterioration with pavement age, cumulative vehicle passes since construction, or both) could not be confirmed for either type of pavement texture.