It's perfectly legal for a Mexican driver to enter the U.S. temporarily under longstanding immigration laws. The advent of North American trucking will test the jurisdiction of laws and regulations where foreign drivers are concerned. As you might imagine, since the U.S.-Mexico border is not yet open to international trucking, for the moment there are far more questions than answers.
Many legal principles have yet to be tested, according to a U.S. government official and a lawyer.
While it is easy to draw a line around a country's sovereignty, things get a little cloudy for transportation workers who cross international boundaries as a normal part of their work. If you're looking at two legal regimes over foreign drivers, you're also looking at potential conflicts, said Howard R. Dobson, an official of the Bureau of International Labor Affairs inside the Department of Labor. In general, foreign labor law is imported with the worker. Conversely, U.S. labor laws and rights apply to American workers on foreign soil. This extraterritorial application of U.S. law has been affirmed by the Supreme Court.