The 17,000-pound solution

The bills known as S. 747 and H.R. 763 may not mean much to the casual observer, but they could be a game-changer for the freight industry. Recently reintroduced in the U.S. Congress at the urging of the Coalition for Transportation Productivity (CTP), the bills are the House and Senate versions of the Safe and Efficient Transportation Act (SETA), a measure that would allow states to raise the gross vehicle weight limit on trucks operating over their portion of the interstate highway system to 97,000 pounds from 80,000 pounds.

In order to qualify for the higher limit, trucks would have to be equipped with an additional, sixth axle to compensate for the extra weight. Proponents say the extra axle makes it possible to maintain the current weight per tire as well as the current braking capacity, which means stopping distances would remain the same. Truck size would be unaffected.

The measure's backers say raising the limit will make trucking operations more efficient. With the current limit in place, it's not uncommon for trucks to max out on weight before the trailer is filled, forcing shippers and carriers to use additional vehicles. Raising the weight limit would allow those companies to use fewer trucks to haul the same amount of freight.

The benefits would extend beyond truckers and shippers to the economy at large. Truck traffic has been growing far faster than road capacity for some time now, and the load will continue to grow. The U.S. Department of Transportation (DOT) has projected that motor freight volumes will jump by 87 percent over 2000 levels by 2020, and the American Trucking Associations has estimated that truck tonnage will double by 2035. Allowing companies to consolidate freight on fewer trucks could be an important step toward averting gridlock of epic proportions.

And the advantages wouldn't end there, according to the CTP and its 180 member firms and associations. Passage of SETA would also have a beneficial effect on roads and bridges, safety, and the environment, they say.

To begin with, the measure would reduce wear and tear on the nation's highways. A DOT study projected that raising the weight limit would save $2.4 billion in pavement restoration costs over 20 years, largely by reducing the number of trucks needed to move a given volume of freight. Furthermore, SETA would require operators of 97,000-pound trucks to pay user fees, with the revenues channeled into a special fund for much-needed bridge repairs.

The highways would be safer as well, proponents say. The single biggest factor in tractor-trailer accidents is the number of vehicle miles traveled, which suggests that any steps taken to minimize those miles would have a corresponding effect on the accident rate. The U.K.'s experience bears that out. In 2001, the U.K. raised the allowable weight on a six-axle truck to 97,000 pounds. Through 2007, tonnage continued to increase, yet vehicles miles traveled remained flat and accident rates declined.

On top of that, several studies have indicated that the measure would cut fuel use and result in cleaner air. For example, a study by the American Transportation Research Institute showed that six-axle trucks carrying 97,000 pounds get 17 more ton miles per gallon than an 80,000-pound truck with five axles. A DOT study estimated that the higher limits would save 2 billion gallons of fuel per year and result in a 19-percent drop in emissions and fuel consumption per ton mile.

It's important to note that no state would be forced to raise truck weight limits. SETA would simply give them the option of setting higher limits on routes they consider suitable for heavier trucks. On balance, it seems to be a good, at least partial, solution to a problem that's not going to go away.