Tables are provided for estimating vehicle operating costs by component on free-flowing low volume rural roads in developing countries. The components evaluated are fuel and oil consumption, maintenance parts and labour charges, tyre wear, depreciation, crew costs and standing charges. They are estimated on a quantity or non-dimensional basis so that costs can be determined for any monetary system or environment by applying the appropriate set of unit rates. operating costs may be estimated for different road geometries, surface condition and altitude and for vehicles of different types with different prices, ages, loads and engine power. The tables are based on research carried out in Kenya by the Overseas Unit of TRRL in collaboration with the International Bank for Reconstruction and Development.