U.S. and Canadian trucking interests have for a couple of years been trying to get U.S. Customs and Border Protection to loosen its restrictions on the movement of empty international trailers, but with no success so far.

CBP's interpretation of the rules promotes business inefficiency, wastes fuel and increases air pollution, say American Trucking Associations and the Canadian Trucking Alliance.

The current rule makes no sense, say officials at both trucking groups. It results in needless double movements of tractors to reposition empty foreign trailers, said Margaret Irwin, director of Customs, Immigration and Cross Border Operations at ATA.

The rules are the same on both sides of the border, but the Canadian government is willing to change if the U.S. will consent, said David Bradley, CEO of the Canadian Trucking Alliance.

"It's a funny little issue but there's an extremely important principle here," Bradley said. "If our governments are serious about making our economies competitive, if they are serious about facilitating legitimate trade, if they are serious about removing archaic bureaucratic barriers to legitimate business, then show us. If we can't accomplish this minor thing, how can they have any credibility in terms of the bigger picture? This for us is low-hanging fruit and if we can't do this then shame on us."

The U.S. and Canadian associations have petitioned half-dozen U.S. agencies for help but the buck has stopped at CBP, which contends that loosening this restriction would grant foreign drivers access to the domestic labor market.

Bradley scoffed at this view. "I would suppose that there are situations where in order to reposition a foreign empty trailer, you would have a U.S. driver with a U.S. tractor pulling an empty Canadian trailer," he said. "And right in front of him or right behind him is a Canadian tractor with a Canadian driver that's bobtailing to the distribution center so he can pick up a loaded trailer to go home. I don't know how many jobs that is, but does that make any sense?"

Bradley said that CBP has expressed concern that if the rule was relaxed, Canadian companies would set up shunt services in the U.S.

"That's ridiculous," he said. "If you enter and exit with the same trailer, an empty repositioning move is allowed. What we have here is an interpretation of the rules from many years ago that appeared in the old customs field manual. We are convinced that if the Department of Homeland Security and CBP specifically wished to make this happen, they could. The fact that they don't is something of a mystery to us."

Both Irwin and Bradley remain optimistic, however.

"There could be some kind of breakthrough," Irwin said. "The Canadians could talk to DHS Secretary Janet Napolitano. We're open to anything."

Bradley put it this way: "If you are tenacious enough and persistent enough, and if what you are proposing makes sense, common sense will prevail. These things sometimes take years, sadly, but we don't intend to simply drop the issue."