WASHINGTON, D.C — An arbitration panel has ruled the U.S. violated North American Free Trade Agreement (NAFTA) rules when it refused allowing Mexican trucks free access to all states.

The panel has nonetheless ruled that the U.S. can require trucks running out of Mexico meet tight U.S. safety standards. The U.S. can enforce its highway safety laws on a case-by-case basis, but cannot ban Mexican trucks outright.

Under NAFTA regulations, Mexico-based trucks were supposed to get unrestricted access to highways in the states bordering Mexico by 1995, with full access to all U.S. highways by January of last year.

The U.S. refused to implement that rule, noting safety concerns and pressure from the Teamsters union.

According to the Department of Transportation, about 35 per cent of Mexican trucks that entered the U.S. in 2000 were placed out of service for safety violations.

Critics of the U.S. ban, however, argued that most of those trucks were on short-haul runs, and so tend to be older and in poorer shape. Mexican long-haul trucks would be newer and in better shape, the critics say.