10 BULLETIN NO. 770, U. S. DEPARTMENT OF AGRICULTURE 
rendered valueless to the operator who must run his trucks under con- 
ditions over which he has little or no control. 
Several factors must be considered in arriving at reasonable cost 
estimates. Among them are: (1) size of truck, (2) probable loads, 
(3) daily mileage, (4) condition of roads, (5) cost of gas, oil and 
repairs. Large trucks necessarily involve increased expenditures for 
operation. The cost of operation per unit of load, however, may he 
less with the large truck than with the small one. The operator whose 
prospective daily mileage will be unusually large must expect that his 
operating costs will be correspondingly large. Where the roads are 
smooth and hard, costs of operation will necessarily be much less than 
Fic. 3.—An open-top stake body, with loose canvas cover, carries a large load of grapes, 
but is not the best type of body for hauling perishable products. 
where the roads are in a poor state of repair or so soft as to be nearly 
impassable at certain seasons of the year. Gasoline, oil and repair 
bills will vary in different sections of the country. It is impossible to 
generalize on these expenses at this point. The prospective operator 
must examine his local conditions, however, and adapt his ideas to the 
prevailing scale of prices. 
In view of the fact that no two individuals operate motor trucks 
under identical conditions, it is necessary that there be some basis of 
calculation applicable under all conditions. Calculations bearing on 
costs of operating motor trucks are customarily based on the “ton- 
mile.” This expression refers to the transportation of a one-ton load 
for a distance of one mile, or the equivalent thereof. The use of such 
