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92 highest frequency of heavy gross loads, but axle loads of 20,000 pounds or more and 22,000 pounds or more are less frequent there than in any other region. This is due to the use of more axles per vehicle and better load distribution among the axles, a condition which is encouraged by State laws and enforcement practices.

These increased traffic volumes and weights, and increased frequencies of heavy concentrated loads, followed a long period in which highway maintenance was curtailed and new construction and modernization was entirely eliminated except for some projects regarded as of special importance in the prosecution of the war. It can readily be seen that the result was the serious obsolescence of our highways as a whole, and especially of the principal, heavily traveled routes, such as those that comprise the interstate system.

VARIETY OF STATE LAWS

A condition that embarrasses the effort to achieve a reasonable uniformity of fitness for service in the highways of the United States is the continuing variety of State laws governing the maximum sizes and weights of vehicles legally permitted to use the highways. The fact that the law of a State fixes particular limits upon the sizes and weights of vehicles that may be legally operated on the roads of the