First, the customs duties and other rules which are maintained in each of the signatory parties to a free trade area and which are applicable at the time of the establishment of such a free trade area shall not be higher or more restrictive for trade with non-parties to such a free trade area than customs duties and other rules which existed in the same signatory parties before the establishment of the free trade area. In other words, the creation of a free trade area for preferential treatment among its members is legitimate under WTO law, but parties to a free trade area should not treat non-parties less favourably than before the establishment of the area. A second requirement of Article XXIV is that tariffs and other barriers to trade must essentially eliminate all trade within the free trade area.  Transportation between the three countries will be more efficient and less costly due to changes in investment restrictions. Under NAFTA, its foreign investment restrictions for motor carriers have been imposed. Since 1995, U.S., Mexican and Canadian carriers have been allowed to create cross-border routes. Prohibitions on such routes off NAFTA made shipping across the U.S.-Mexico border costly and inefficient; The goods had to be unloaded from one truck and placed on another truck when transported from Mexico to the United States or vice versa. With the entry into the twenty-first century, trade between the United States and Canada is free for a variety of reasons. For example, since January 1999, a database of driver data has been available to law enforcement officers in each of the three NAFTA countries. But border crossing procedures at the U.S.-Mexico border remain ineffective. In January 1996, an agreement was to enter into force, which would allow the United States, and Mexican carriers to pick up and deliver international shipments to states adjacent to the U.S.-Mexico border, but the agreement was blocked by the United States.
Commentators believe the decision was based on organized workers` opposition to NAFTA. In addition, the United States and Mexico are still working to harmonize safety standards for motor carriers. These occur when one country imposes trade restrictions and no other country responds. A country can also unilaterally ease trade restrictions, but this rarely happens. This would put the country at a competitive disadvantage. The United States and other industrialized countries are only doing this as a kind of external aid to help emerging countries strengthen strategic industries that are too small to be a threat. . . .