Under the 1993 North American Free Trade Agreement (NAFTA), Mexican truckers were promised access to all U.S. highways by the year 2000, as was access through Mexico for U.S. carriers. But although a similar exchange with Canada has already been enacted, an agreement with Mexico has yet to be reached, according to The Associated Press. U.S. trucking companies, unions and environmental groups point to Mexico’s loosely regulated trucking industry, saying that trucks used by Mexican carriers are older and poorly maintained, due to less stringent environmental and safety standards. Opponents also say the provision will cost Americans thousands of jobs, pollute the air, damage highways and threaten national security. Mexican carriers insist their rigs meet U.S. standards. Meanwhile, however, their trucks can’t go beyond a 20-mile border zone in Texas, The Associated Press reports. Mexico has said the United States is reneging on part of its NAFTA role, and a February 2001 international arbitration panel agreed. President Bush said in 2001 said he would allow the trucks. And in a June 2004 unanimous decision, the U.S. Supreme Court said that the president—not federal agencies—had ultimate say on whether the trucks could enter. But two and a half years later, the trucks are still prevented from entering the U.S. A spokesman for the Federal Motor Carrier Safety Administration and for the Bush Administration on the trucking issue, said a safety plan for Mexican trucks is ready, should the highways be opened, but added that negotiations with Mexico are ongoing. Joan Claybrook, president of Public Citizen and the former head of the NHTSA, said the sticking point is legislation calling for U.S. inspectors to perform safety checks at trucking companies in Mexico, a policy she said the Mexican government would not agree to. She said Public Citizen is also working on legislation requiring drivers from Mexico to have "black boxes" to record driving hours and prevent fatigue, something the group also is seeking in the United States.