Citation

Mahone DC. Transp. Res. Rec. 1976; 602: 69-71.

Copyright

(Copyright © 1976, Transportation Research Board, National Research Council, National Academy of Sciences USA, Publisher SAGE Publishing)

DOI

unavailable

PMID

unavailable

Abstract

Three major factors that influence the skid number and speed gradient were studied: tire tread depth, water film, and pavement surface texture. Only the effect of pavement surface is discussed in this report. The pavements were catagorized into three groups: steep gradients, (G) intermediate gradients, and flat gradients. Thirty one sites were investigated for each of the three catagories of gradients. Data was analyzed and evalauted. The results show that high speed gradient values are common to pavements that do not have a relatively high degree of macrotexture. The highest skid numbers recorded in the study were at low speeds in the steep gradient group, which means that a low macrotexture and a high macrotexture provide the best skid-resistance surface at low speeds. The opengraded mixes, which provide flat gradients, provide a very desirable surface for high-speed traffic. Grooving does not improve the skid resistance or the G value for treaded tires. Because grooving does not decrease the G value, it is suggested that the mere provision for water escape does not guarantee that the pavement surface will have a flat gradient.