The mileage obtainable per tire cycle — original plus recapping mile- 

 age — is modified by the time factor. As more years are involved in the 

 cycle, total mileage falls. Hence, a modified iiormiila, similar to that 

 derived by Clarke and Bressler,- was used to determine total mileage 

 obtainable with various levels of annual mileage: 



TY = 



m' + 4,240 



In the preceding equation, T Y := tire life in years; m = normal 

 miles obtainable from tires for the particular truck size; m' =: annual 

 miles of travel. To obtain the annual cost for tires (and tubes), the fol- 

 lowing equation was used: 



r 



TC = 



TY 



in which C =^ the dollar cost per tire cycle for original purchase plus 

 recappings and TC r= the annual dollar cost. 



Gasoline. As truck size increases the number of miles obtained per 

 gallon declines. On the basis of data obtained in the survey and from 

 secondary sources, gasoline con^iumption was assumed to decline from 

 16 miles per gallon for the smallest truck size to 5 miles per gallon for 

 a tractor. A price of 25c per gallon of gasoline was used. 



Other investigators have divided gasoline consumption into a fixed 

 amount per day plus a variable component related to miles travelled." 

 However, the size of the fixed item is likely to be of minor importance 

 for trucks such as those used in poultry assembly, whereas for delivery 

 truck* making numerous stops it would be relatively larger. 



Other Fixed Operating Costs. These include: registration and license 

 fees, bonding charges, and purchase of anti-freeze. Registration and 

 bonding costs were established in relation to truck capacity by inter- 

 polatins fi'om information obtained on field schedules. License cost's 

 were established at $3 per vehicle, the modal value of charges levied 

 by the New England states when transfer costs were included. Cost of 

 anti-freeze. at $2 per gallon, was determined by radiator capacity. Pro- 

 vision was made for temperatures of -30°F. 



Federal Excise Tax. This has been included at $1.50 per year for each 

 1,000 pounds taxable gross weight paid by registrant on truck combi- 

 nations over 26,000 G.V.W.^ 



- Clarke, D. A., Jr., and R. G. Bressler, Jr. Efficienry of Milk Marketing in Conner- 

 ticut: 6. Truck Costs and Labor Requirements on Milk Delivery Routes. Storrs 

 (Conn.) Agr. Exp't. Sta., Bui. 248. June 1943, p. 8. 



Y ^ ; Y =r years of life; R ^ the annual rate of travel. 



R + 4,240 



This formula was intended to apply only to tires with a life of 20,000 miles. 

 For other situations the factor of 4240 should be adjusted. 



■'' Clarke, D. A. Jr., and Bressler, R. G., Jr., op.cit., p. 4. 



* Motor Truck Fnrts, Automobile Manufacturers Association, Detroit, Michigan, 

 1957 Edition, p. 28-33. 



47 



