26 BULLETIN 136, U. S. DEPARTMENT OF AGRICULTURE. 



Financing maintenance. — It is undoubtedly necessary, in gene- 

 ral, to establish a direct tax for annual repair and maintenance for 

 bond-built highways. 1 When highway bonds are issued it should be 

 distinctly understood that there will be (besides the tax for interest 

 and retirement) withm a few years an additional tax for repair and 

 maintenance, if the regular road tax within the county, as is most 

 often likely, is not already sufficient to repair and maintain the new 

 roads. This repair and maintenance charge is inevitable and, since 

 the earning power of the road in reducing hauling costs tends to in- 

 crease with the degree of maintenance, it is sound business to face the 

 repair and maintenance charges hi the beginning. 



Comparisons of total costs. — When the more expensive types 

 of highways are to be built by the proceeds of a bond issue, especially 

 under increasing traffic, a question may fairly arise as to the relative 

 portions of the total cost for a series of years, which should be devoted 

 to repair and maintenance and to first construction and interest. As 

 Table 5 shows, the cost of the hard highway surface constitutes, for 

 standard types of construction, the largest percentage of total costs. 



Up to a certain point, when the cost of the surface is increased, 

 the cost per mile of maintenance correspondingly increases, but not 

 usually the cost per unit of traffic. It costs more per mile to repair 

 and maintain an ordinary macadam road, for example, than it does to 

 repair and maintain a gravel road, and the cost per mile of repair and 

 maintenance for bituminous-macadam roads is greater than for 

 ordinaiy macadam roads. The costs of repair and maintenance of 

 the best-built brick and concrete roads are apparently very low, and 

 would, therefore, not follow the above rule. 



The total necessary cost of a highway for a series of years can be 

 determined only approximately and only after a study of the charac- 

 ter and volume of traffic and a comparison of the total probable costs 

 for the kinds of surface adapted to the traffic. It may not be economy 

 to build a road of cheap first cost and high maintenance charges. If 

 exact figures were available, accurate comparisons of different sur- 

 faces would be simple, but many items are still lacking. It is not 

 known how long a concrete road will wear or what it will cost to 

 renew it, especially if it has to be broken up and removed. The life 

 of bituminous-macadam roads has not yet been fully determined, 

 nor has the life of the best modern vitrified brick pavement. Abso- 

 lute maintenance 2 on most pavements can seldom be continuous. 

 Repairs or resurfacing operations will be needed at intervals which 

 are as yet imperfectly determined. 



1 Cf. Act of September, 1913, by Legislature of Tennessee, which establishes a maintenance tax of 

 2 per cent of all highway bonds. 2 See Bulletin No. 48 of the Office of Public Roads, p. 8. 



