Too Heavy?

In the last decade, the number of trucks on U.S. highways has risen from 4,590,000 to 8,200,000. Since the trucks themselves have grown bigger, the amount of freight carried has risen even faster, from 51 billion ton-miles a year to 115 billion. Has this enormous new traffic damaged U.S. highways and, if so, how much?

To find out, Ohio's Governor Frank J. Lausche got the highway directors of 16 Midwest and Eastern states to form the Inter-Regional Council on Highway Transportation. Last June the council started tests to measure the damage. Maryland set aside a 1.1-mile stretch of modern, two-lane concrete highway, the Automobile Manufacturers Association provided trucks, and Engineer Asriel Taragin of the U.S. Bureau of Public Roads was put in charge.

Back & forth, day after day went the trucks, loaded with concrete blocks. On one half-mile section ran single rear-axle trucks loaded with 18,000 Ibs. (now the legal limit in 34 U.S. states) and on another, trucks with 22,400 Ibs. (Maryland's own present limit). On two other stretches ran trucks with tandem axles (two in the rear), carrying loads of 32,000 Ibs.which highway engineers recommend as a maximumand 44,800 Ibs., which six states presently allow.

Last week, at the annual meeting of the Highway Research Board in Washington, Engineer Taragin gave his preliminary findings. P: After nearly four months, traffic on the lane devoted to the 44,800-lb. load was stopped because the road was so badly damaged. It had developed 3,303 ft. of cracks after 92,166 truck passes; 96% of its slabs had been damaged. In the same number of passes, the 32,000-lb. tandem-axle load had caused 307 ft. of cracks and damaged 27% of the slabs. P: After six months and 238,000 passes of the single-axle truckloads, the 18,000-lb. load had caused 241 ft. of cracks and damaged 28% of the slabs, while the 22,400-lb. load had caused 1,210 ft. of cracks and damaged 64% of the slabs.

At the news, the American Trucking Associations' spokesman, Walter Belson, cried angrily that the Maryland road tests proved nothing. The soil under the road was so poor, said Belson, that it got washed out, causing the road to crack.

Governor Lausche, however, thought the evidence was plain. In a message to the Ohio legislature last week, he said: "Large trucks with heavy cargoes definitely damage the highways far in excess of the proportionate gross weight of such trucks compared to the gross weight of ordinary motor vehicles . . . Trucks carrying heavy loads are not contributing their fair share for the construction and maintenance of the roads of Ohio." Lausche recommended that Ohio tax heavy trucks on the basis of the ton-miles of freight they haul in addition to a license fee. (Maryland was already considering a similar tax.) Some truckers, who can only make money with huge loads, prefer to pay fines if necessary than to haul an "uneconomic" load. As proof of how widespread the practice is, Lausche's state police last fortnight stopped 4,000 trucks on busy Route 40, and found 356or 9%overloaded.

It looked as if more states would soon stop overloading, and make outsized U.S. trucks pay more for their heavier use of the highways.

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