At first read, a new proposal to establish national standards for fuel economy and greenhouse gas emissions appears to offer a workable approach for the trucking industry, said Glen Kedzie, vice president and environmental counsel for the American Trucking Associations.

But there are some concerns about the 673-page proposal, he added, not the least of which is a potential conflict between what the federal government is proposing and what California is doing.

The federal proposals by the National Highway Traffic Safety Administration and the Environmental Protection Agency will establish standards for heavy-duty and medium-duty tractors, and for engines, starting in 2014. Trailers are not covered.

In recognition of the variety and complexity of trucking operations, the standards will be based on the work the truck does - gallons per ton-mile and grams of carbon dioxide per ton-mile, rather than the traditional miles per gallon and grams per brake horsepower hour.

The standards, which will vary among truck and engine types, will achieve fuel and emissions savings between 7 and 20 percent between 2010 and 2017, the agencies said. These gains will mainly be achieved through improvements to engines, tires, the aerodynamics of the truck and reduced idling - technologies that have been proven through the EPA's voluntary SmartWay program.

This performance-based approach is somewhat at odds with what the California Air Resources Board is doing, Kedzie said. CARB is requiring, for example, that if a carrier is using certain 2011 and newer tractors to pull 53-foot or longer trailers, both the tractor and trailer have to be SmartWay-certified.

"So if you're operating in Cali­fornia, with certain exemptions and exceptions you have to have SmartWay-certified tractors and use SmartWay-approved low rolling resistance tires when you go to California," Kedzie said.

His concern is that the California approach and the federal approach are not exactly aligned, especially since trailers are not included in the federal proposal.

"We don't want a patchwork, a California approach and a federal approach," he said, adding that ATA intends to closely follow ongoing discussions between the federal agencies and CARB.

The federal approach is more palatable to trucking because it is more flexible, he said.

Another concern: ATA wants to make sure that the green partnerships that have grown up under SmartWay are preserved.

"We have endorsed SmartWay and many carriers have worked hard to comply with SmartWay," he said. "We want to make sure SmartWay stays in effect because we don't want to jeopardize these relationships."

A third concern is that carriers may find the range of equipment choices available to them has shrunk, if manufacturers decide the best way to meet the efficiency and emissions targets is to stop offering certain engines or tractors.

The critical element in that decision will be the target itself, he said. The agencies are proposing, for example, that 70 percent of all Class 8 sleeper cab high-roof tractors be SmartWay certified for aerodynamics by 2014. That probably is a reasonable goal, since the agencies were acting on information given them by truck manufacturers and the manufacturers probably built in a margin of error, but it is not a sure thing, Kedzie said.

Carriers will be able to spec equipment as they have always done, and it will be up to manufacturers to make and market the equipment that meets the standards.

"We will have to wait and see if the OEMs can hit their targets," he said. "The market will find ways to direct people towards buying the more efficient equipment."

ATA is pleased to see that the proposal includes several elements of the sustainability plan it put together a couple of years ago, Kedzie said. These include reduced truck speeds, decreased idling, use of off-the-shelf technologies that have been proven through SmartWay, and fuel efficiency standards that are technologically and economically feasible.

"We're pleased that they're heading down that path and that they're thinking along the same lines that we're thinking," he said.

Comments on the proposal, which was published in the Nov. 30 Federal Register, are due by Jan. 31. The final rule is due by the end of July.