A thesis submitted in partial fulfillment of the requirements for the degree of Master of Engineering of the Asian Institute of Technology, Bangkok, Thailand.

Thesis (M.Eng.) - Asian Institute of Technology, 1973

Skidding has been shown by many investigators as a contribu tory factor to road accidents, especially when road surfaces are wet. There are no accident data available in Bangkok from which the contribution of skidding to road accidents can be assessed. An estimate made of the period of time when the road surface is wet suggests that this is of the order of 3 percent of a year. Measurements of skid resistance value were made on different types of road pavement surfaces --namely, Portland cement concrete, bituminous seal-coat, bituminous semi-grout) and bituminous plant mix surfacings -- occuring in Bangkok. Laboratory experiments have been made to determine the polished-stone value on a range of road stones which are available in Thailand. Basalt, as a group, have shown long-lasting skid resistance characteristics. Although the wet road surface time is small, a large number of surfaces are dangerously slippery when wet.