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.
Abstract