Page:Needs of the Highway Systems, 1955–84.pdf/18

14 Simply to sustain the investment in the highway plant at the stage of development existing at the end of 1964 will require substantial continuing capital outlays in the years after 1964. For example, by the end of 1964 the highway plant then in service will represent an investment (cost new, 1954 prices) of $140 billion to $150 billion. On the basis of a 30- to 35-year life of investment, it would require an average construction expenditure of $4 billion or more annually to offset the depreciation which would be taking place. In addition, as highway facilities wear out and require rebuilding, provision must be made for substantial upgrading to take care of still further traffic growth.

In recognition of these future needs in the years following the initial 10-year period, each State supplied an estimate of such costs for each road system for the 20-year period 1965–84. These costs as reported by the States, amounted to $114.4 billion for all road systems combined. The distribution of this total by systems is shown in table 4.

Significant relations are revealed by en the capital outlay amounts during the 20-year period 1965–84 (table 4) with those for the initial 10-year period 1955–64 (table 2). Probably the most important is that for the interstate system. The needs from 1965 to 1984 are less than half the needs for the first 10 years, 1955–64. For other road systems the 1965–84 needs are greater than those of the initial 10-year period. The reason for this, of course, is that the 1955–64 estimates for development of the interstate system provide that by 1964 it shall be adequate for 1974 traffic. This substantially delays the accrual of replacement needs for a considerable period after 1964. The estimates for other road systems are based on the assumption that they will be adequate by 1964 for 1964 traffic, thus requiring continuing construction, reconstruction, and upgrading of wornout sections in substantial amount in 1965 and later years.