Abstract
Tables for estimating vehicle operating costs on rural roads in developing countries have been published by the transport and road research laboratory. This report gives guidance to users of these operating cost tables on values of surface roughness, rut depth, depth of loose material and surface moisture content which correspond to various road construction standards, traffic loadings and growths and for different maintenance policies. The values of road deterioration parameters given in this report are based on field observations made by the laboratory in Kenya. (Author/publisher).