The study undertaken in 1992 identified the factors that contribute to the costs of operating vehicles on unsealed roads compared to those costs on sealed roads in New Zealand. However, the results of a review of international literature and of the vehicle operating costs obtained from a survey of New Zealand transport operators indicated that road surface type (unsealed or sealed) was not a significant source of cost differences over that attributed to increased road surface roughness. Any effect of road surface type is unlikely to exceed 5% of total vehicle operating costs.
The study reinforced the notion that road surface roughness is a significant determinant for vehicle operating costs. Also it showed that the relationship currently used in the Transit New Zealand Project Evaluation Manual (1991) is appropriate for unsealed roads.
Keywords: Costs, paved roads, pavement, roads, sealed roads, transport, unpaved roads, unsealed roads, vehicle operating costs