The performance of earthmoving plant is currently estimated through experience, often with no more than a limited inspection of the site investigation report. On site, the absolute speed of the plant is seldom considered to be critical as long as the veheciles keep moving. The different factors which affect the speed of the plant on the haul roads are discussed. The various soils test which were carried out, as well as how they relate to the apparent rolling resistance of the driver-vehicle-haul-road system, are discussed. Also, the reasons why certain tests are inadequate for the estimation of the performance of earthmoving plant are discussed. It is shown that the speed of the plant can be estimated from the data contained within the site invesitigation report, and that it can be continually monitored throughout the life of the contract, by using the consistency index.