President Barack Obama has set a laudable goal of doubling exports within five years, but success will depend on preventing the loss of key markets such as Mexico, one of our biggest trading partners. That's why the administration should move quickly to resolve the long-festering dispute over access for Mexican trucks to the United States. A five-member arbitration panel has already ruled that Washington's ban violates the North American Free Trade Agreement. In response, Mexico has imposed tariffs of more than $2 billion on U.S. products. Soon after taking office, Obama signed legislation that wiped out a pilot program allowing access for Mexican trucks, subject to U.S. safety rules. The Federal Motor Carrier Safety Administration said no accidents involving Mexican trucks had occurred. Allowing trucks to cross the border creates substantial transportation savings — estimated at $400 million a year by the U.S. Department of Transportation — because it does away with the needless unloading, warehousing and reloading that is otherwise required. These savings could be passed on to consumers.