The trade groups representing the nation's railroads and big truckers have jointly called on the House of Representatives to exclude any provisions that would change truck size and weight limits when the chamber begins debating a bill reauthorizing funding for the nation's highways.

In a joint letter signed by Edward R. Hamberger, president and CEO of the Association of American Railroads (AAR), and Bill Graves, president and CEO of the American Trucking Associations (ATA), the groups urged House members to "oppose any floor amendments" that would allow longer and heavier trucks on the nation's interstate highways.

The letter, released late Thursday, deals a potentially devastating blow to efforts to make the biggest changes in commercial truck size and weight limits in 30 years. As part of a five-year, $260 billion funding bill introduced by Rep. John L. Mica (R-Fla.), chairman of the House Transportation and Infrastructure Committee, the language would have allowed a single-trailer truck with a gross vehicle weight of up to 97,000 pounds to operate on the nation's interstates, as long as each truck was equipped with a sixth axle to maintain braking and handling characteristics at the higher weights.

The current limit is 80,000 pounds on interstate highways running through all but six states.

However, the language ran into trouble when the full committee, which approved the bill, called for a three-year feasibility study by the Transportation Research Board into the truck size and weight issue. Despite that, there had been talk of the provision being inserted as an amendment during floor debate in the full House.

"While we're disappointed that some of the productivity provisions relating to weight and harmonization of [longer-combination vehicles] did not survive the committee process, there are some significant productivity gains that remained in the bill," said the ATA in a separate statement. "Beyond that, there is a great deal for trucking to like about the House bill—ranging from crashworthiness standards to the creation of a drug and alcohol clearinghouse on the safety side to the refocusing of the federal program on national needs like freight movement.

"What this agreement allows us to do is take one potentially controversial issue off the table in the interest of moving the legislation, which is nearly 30 months overdue, forward," the group said in the statement.

The ATA's comments reinforce its lukewarm feeling toward the provision, as well as its desire not to let it stand in the way of progress to pass a multiyear reauthorization bill. The last multiyear law expired in September 2009 and has been living on short-term extensions since then.

AAR, which has for years fought federal efforts to raise truck size and weight limits, said the operator of a typical 97,000-pound, six-axle truck pays only half of the cost of repairing road damage caused by its use. Taxpayers pick up the rest of the tab, the AAR said.

The railroads argue that they pay the full cost of infrastructure improvements, while truckers have a large portion of their highway use subsidized.