Economic constraints upon vehicle axle loading in developing countries.

The principal economic constraints on road transport are shown to be fuel cost, axle loading, and mass of payload transported. Using recent Zimbabwean costs it is shown that whilst a doubling of diesel cost will reault in only small overall cost increases, the road costs will vary from less than half a cent per payload tonne-km for heavily, to as much as 25 cents for lightly trafficked roads. From this it is suggested that any trans-continental road in Africa would be sub-economic.