According the this report on Forbes.com, Mexican tractor and trailers will be allowed to travel anywhere in the United States starting Saturday. Teamsters officials announced plans to seek an emergency injuction to prevent the implementation of the cross-border entry. Currently, Mexican trucks are required to stop in a 'buffer zone' and transfer their loads to US trucks.
I must admit, it's not often that I find myself in agreement with the Teamsters AND the Sierra Club, but the USDOT has enough problems enforcing standards and laws for our own trucking interests.
In my opinion, allowing Mexican trucks on US interstate highways will be taking loads from the generally safe US trucking companies and giving the bread and butter of those drivers to someone who could be smuggling narcotics, illegals, or even weapons into our country. This step is a dangerous leap forward into the Security and Prosperity Partnership. It is this organization that skeptics say will lead ultimately to the dreaded North American Union. To my thinking, this is more about practical concerns, specifically the safety and the security of America's truck drivers.