The U.S. average factors for all Federal-aid systems combined, including estimated secondary factors, for the years 1958, 1959, and 1960 are as follows: Where the factor "0" appears in the tabulation it indicates that none or a negligible quantity of the material was reported. The dotted lines indicate that no construction was reported on the particular system for the State shown. EXHIBIT J HIGHWAY CONSTRUCTION USAGE FACTORS FOR LUMBER, TIMBER PILING, PETROLEUM PRODUCTS, AND EXPLOSIVES, 1958–60 DISCUSSION This is the sixth in a series of tabulations showing highway construction usage factors for lumber, timber piling, petroleum products, and explosives for 3-year periods. The first of the series was based on the years 1953, 1954, and 1955 and the fifth of the series covered the years 1957, 1958, and 1959. An important phase in highway construction planning is the estimating of future requirements for materials in order that industry may be geared to supply such materials. Of the various materials used in highway construction, steel and aggregates constitute the largest elements of cost, together amounting to more than 50 percent of the cost of all materials and supplies and about 30 percent of the total construction cost (not including the cost of right-of-way and engineering). The approximate comparable percentages for the materials in this tabulation are as follows: The usage factors for lumber, timber piling, petroleum products, and explosives are intended to aid producers, manufacturers, and suppliers of these commodities and related industries, as well as highway contractors, engineers, and economists in planning to meet the needs of the expanded highway construction program in the United States. These factors when applied to expected contract construction expenditures for both Federal-aid and non-Federal-aid highway construction, will generally result in reasonably accurate estimates of requirements. The data used in the development of the usage factors are supplied by contractors for projects on the Federal-aid primary system (including interstate). Investigations have indicated that for comparable standards of design, materials usage factors for non-Federal-aid work do not differ appreciably from those developed for Federal-aid construction. Information for computing Federal-aid secondary factors, by States, is not currently reported. It is recommended, therefore, that the State secondary factors on the tabulation of January 1958, covering the period 1954–56, be used for reasonably accurate estimating purposes. It should be recognized that the factors shown for individual States, in some instances, may not be truly representative of normal usage because of being based on low volume of work and/or temporary disproportionate percentages of the three major classifications of highway construction, i.e. grading and drainage, surfacing and structures. In some States, however, during the 3-year period, the volume of work is large enough and the type distribution is of suitable proportion to reflect fairly representative usage factors. As in previous tabulations of the series, the elimination of data for the first year of the last edition and the inclusion of data for the most current complete year resulted in some significant changes in the factors for some States. Generally the U.S. average factors for timber piling and explosives have increased to some extent as compared to the previous issue, while those for lumber and petroleum products have decreased. The U.S. average factors for all Federal-aid systems combined, including estimated secondary factors, for the years 1958, 1959, and 1960 are as follows: Where the factor "0" appears in the tabulation it indicates that none or a negligible quantity of the material was reported. The dotted lines indicate that no construction was reported on the particular system for the State shown. EXHIBIT K TABLE 1.-Estimate of annual highway material usage, 1962-72 |