Teamsters are protesting the launch this week of a program allowing Mexican trucks to travel anywhere in the US, rather than just 20 miles inside the border. Union officials argue that Mexican trucks aren't safe because they're subject to different environmental and inspection standards, and that regulations regarding shifts and drug use will be difficult to enforce.
Unions also fear a pay drop forced by the availability of cheaper Mexican labor. The program allows a few companies from both countries to obtain permits to criss-cross the Rio Grande. The North American Free Trade Agreement requires that the US, Canada and Mexico open their roads to each other.