an average annual expenditure of at least $750,000,000 will be required for several years after the war, an amount that may have to be exceeded in the first years to catch up as quickly as possible with needs deferred because of the greater necessities of the war. The conservatism of this estimate is indicated by the fact that highway and street maintenance expenditures, clearly so recognized, in the 4 years, 1939–42, averaged $640,000,000 per year, as shown on table 24, and these expenditures were doubtless augmented by part of the work- relief expenditure, averaging $427,000,000 in the same period, which was made for essentially maintenance purposes. The post-war maintenance expenditure, whatever may be its reasonable amount, must be made as early as possible in order to halt the road and street deterioration which wartime neglect has permitted; and it should have first call upon the post-war current highway revenues of the States and their subdivisions.
The additional amount it will then be possible and desirable to expend for highway construction will depend upon the magnitude of the national income and the requirements of private construction and maintenance and other kinds of public construction.
It has often been suggested that the national income should not be allowed to fall below $100,000,000,000. On the assumption that this is a desirable minimum, the Committee considers the expenditure of approximately 15 percent of that sum, or $15,000,000,000, as reasonable and desirable for all classes of construction and maintenance, public and private.
The maximum past expenditure for private construction and maintenance was the average of just under $10,000,000,000 recorded in the 4 years 1927–30 (table 22). In the 4-year period leading up to the war the private expenditure averaged approximately 6.5 billion dollars per year. With due allowance for a substantial expenditure for housing and expecting that the conversion of war plants will reduce the construction essential for resumption of peacetime industry, the Committee estimates that the post-war requirement of private construction will not exceed an average of $8,000,000,000 per year, or 8 percent of a national income averaging $100,000,000,000. This will leave a balance of $7,000,000,000 of the desirable $15,000,000,000 total for all kinds of construction to be employed for public construction and maintenance of all classes.
Referring again to table 24, it will be observed that in each of the 4-year periods for which public construction expenditures are summarized, excepting only the period 1915-18 when highway improvement had been scarcely begun and the period 1939-42 when war reparation made its extraordinary demands, the expenditure for highway construction and maintenance was substantially equal to or in excess of the expenditure for all other classes of public construction and maintenance. A similar division will be observed in the work-relief expenditures of the three 4-year periods from 1931 to 1942, inclusive.
An equal division of the $7,000,000,000 estimated above as likely to be available for all classes of public construction immediately after the war, would allot to post-war highway construction and maintenance 3.5 billion dollars. As will be seen from table 24, this amount substantially exceeds the largest previous sustained highway expenditure. Nevertheless, the Committee considers that all necessary preparations
