Off-highway dump trucks, from small 18 ton to huge 160 ton capacity, are usually driven on unpaved job site road rougher than paved roads where automobiles are driven. It is not rare for off-highway dump trucks to be operated in the same job site for more than five years and to make more than ten thousand round trips on the same roads. Therefore, the condition of the haul road strongly affects the dump trucks' endurance and performance.First, this paper describes the road profilometer which was designed to measure off-highway road roughness using a Laser beam. Second, this paper talks about the haul road conditions for off-highway dump trucks by world-wide job site surveys. Then, the paper expresses how loading weight, vehicle speed and road roughness affect the endurance and riding comfort of off-highway dump trucks. Finall, the paper describes briefly field and laboratory tests for off-highway dumpers based on worldwide job site surveys.