This multiyear study provided answers to two important questions--what is the relationship between wet-pavement accidents and tire-pavement skid resistance; and what countermeasures can be employed with economic justification. Accident rate, skid number, and related data were collected for two, 1-year periods on 428 highway sections in 16 states. Extensive statistical analyses showed that a linear relationship between wet-pavement accident rate and skid number provided a reasonable fit to the data. Moreover, the slope of the ralationship (decrease in accident rate with increased skid number) was independent of highway and area types and ADT, although the magnitude of the accident rate did depend on such factors. These findings and others were incorporated into an extensive, computerized benefit-cost model for wet-pavement accident countermeasures involving surface treatments as well as geometric, traffic control, and other remedial measures. The study also thoroughly examined surface macrotexture, which is an important determinant of skid resistance, and summarized means of measuring it and modifying or controlling it.