As vehicle size and weight increase, gasoline consumption per mile 

 increases. From data furnished hy a secondary source, a relationship 

 was developed between gross vehicle weight and miles per gallon of 

 gasoline. Vehicle types M, N, and O get 8.6 miles per gallon, and types 

 P and Q get 8.2 and 8.0 respectively. Gasoline has an assigned cost of 

 25 cents per gallon. 



Oil consumption is a function of mileage and oil capacity of the 

 motor. It is assumed that oil changes are made at intervals of 2,000 

 miles, and assigned amounts are added between changes. Vehicle types 

 M, N, and O require 7.2 quarts for every 1,000 miles, and types P and Q 

 require 8.9 and 9.0 quarts resiiectively. Oil has an assigned cost of 30 

 cents per quart. 



Lubrications are performed at 1,000 mile intervals. Assigned costs 

 for each vehicle type are as follows: $2.25 for types M, N, and O; $2.50 

 for type P; and $2.75 for type Q. 



Tire cost is a function of mileage and time. Information and data 

 from a secondary source indicated that tires have a useful life of six 

 years or 90,000 miles. Thirty thousand miles is derived from the original 

 tread. Tread is replaced by recapping, and a maximum of three re- 

 cappings is assumed in this study. Each recapping is assumed sufficient 

 for an additional 20,000 miles. The five vehicle types have the same 

 tire size and ply and each vehicle has six tires (dual rear wheels) and 

 a spare. New tires cost $110 and each retread costs $30. In some cases, 

 permissable tire mileage exceeds the mileage on the trucks at the time 

 of the trade-in. Tire costs were adjusted to take this factor into consider- 

 ation. 



Truck chassis and body maintenance and repair costs are a function 

 of mileage and time. As truck mileage increases over a given period of 

 time, these costs decrease on a per mile basis. Maintenance and repair 

 costs were derived from the equation: 



MR = <^ + *^-J'' -"'^ M- 

 M 



MR = Annual maintenance and repair cost 



C := Cycle cost of maintenance and repair by truck type 

 Y = Years to major overhaul at M' miles per year 

 X ^= Years to major overhaul at a rate of 10,000 miles 



per year 

 N = New cost of truck body and chassis in dollars 

 M r= Miles in cycle to major overhaul 

 M' rr: Annual mileage 



Table C-2 shows the constants developed for use in the equation. 



Annual maintenance and repair costs for vans are considerably less 

 than for truck chassis and cabs. For purposes of this study, this cost was 

 fixed at a half on one percent of new van investment for the first 20,000 

 miles of annual travel. For additional mileage, the cost increases at a 

 rate of one haK on one percent of new investment for each 20,000 miles. 



54 



