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.'| When highway bonds are issued it should be 
distinctly understood that there will be (besides the tax for interest 
and retirement) within 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 in 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 
ordinary 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? on most pavements can seldom be continuous. 
Repairs or resurfacing operations will be needed at intervals which 
are as yet imperfectly determined. 
1Cf. 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. 
