Why do railroads care so much about a trucking industry productivity issue?

Why does the public care? Why do the American Automobile Association, the Sierra Club, Environmental Action, the Teamsters Union, the National Taxpayers Union and the Center for Auto Safety - among others - care?They care because, to the trucking industry, productivity means the ability to fill longer and heavier trucks. When even current truck sizes scare many highway drivers, the trucking industry wants the public to share the road with trucks up to 135,000 pounds and as long as 120 feet.

Railroads care because bigger trucks could divert so much freight - and force down rates on so much of the rest - that large segments of the industry might be forced into bankruptcy and attendant massive layoffs and abandonment of rail service that is vital to many communities.

If truckers - like railroads - owned their right-of-way or paid all costs for which they're responsible, perhaps this could be justified as the normal workings of the free market.

But they don't. According to the federal government, a 72,000-pound rail-competitive truck pays less than 60 percent of its pavement repair responsibility. This does not even count other indirect costs, such as congestion, pollution and the costs a private citizen pays to repair front-end damage done by the ruts and potholes inherent in many truck corridors.

The subsidy is even greater for 80,000-pound trucks, since they use less fuel - and hence, pay lower fuel taxes - per ton-mile of freight generated.

But the trucking lobby has now decided that the current limit of 80,000 pounds is not enough. With the federal highway program up for reauthorization next year, the truckers are seeking permission to use even longer, heavier trucks - twin 53-foot and triple 28-foot trailers that would be nearly half as long as a football field.

Truckers recognize that the public opposes nationwide operation of longer and heavier trucks. So the American Trucking Associations says it no longer plans to ask Congress to mandate longer combination vehicles. Rather, it wants to ask Congress to permit the states to allow longer, heavier trucks.

Nostradamus I am not, but let me predict what will happen - because it has happened before. These requests for state by state approval of truck size and weight increases today will become demands in Congress for mandatory national limits in the future.

In other words, ATA will ask Congress to authorize states to determine higher weight limits. Then it will lobby hard at the state level and play recalcitrant states off against more pliable ones.

The final step is to demand uniformity from Congress, thus transforming the optional maximum into a mandatory minimum.

This is what happened between 1974 and 1982. Seeking a permissive increase from 73,280 to 80,000 pounds, the ATA testified before Congress that: "No state, under the industry's proposal, would be required to make any change whatsoever . . ."

By 1979 this had become: "For the industry to achieve nationwide productivity benefits accruing from the higher weight limits, the mandating of these standards by the federal government may be the only practical approach."

Sure enough, in 1982, the 80,000-pound weight limit became mandatory nationwide.

We can't again let trucks grow still heavier - or longer.

(William H. Dempsey is president of the Association of American Railroads.)