Optimum Axle Loads of Commercial Vehicles in Developing Countries

摘要

The Road Transport Investment Model for developing countries has been used to examine the effects of different axle loading characteristics on the total costs of road transport. It is shown that the sum of vehicle operating costs, road construction costs and road maintenance and rehabilitation costs for a two lane highway initially decrease rapidly as the axle load of the most heavily loaded vehicles increases and passes through a shallow minimum at the optimum axle load. The value of this optimum axle load was found to be strongly dependent on the total freight tonnages carried by the heavily loaded vehicles, the load condition of these vehicles on the return trip, the exponent of the pavement damage -- axle load relationship, and the relative prices of the major components of road transport cost. The optimum axle load was found to be virtually independent of the road alignment and strength of the subgrade, but the road construction and strengthening policy and the composition of the vehicle fleet had a small but significant effect on its value. (Copyright (c) Crown Copyright 1981.)