Senator Byron Dorgan (D-ND) reportedly said the Department of Transportation (DOT) authorized the program too quickly, in view of a report that found a number of problems with Mexican truck safety records.  Supporting the test, Senator John Kyl (R-AZ) was quoted as saying that it would be worth giving the program a chance because it is more efficient and less costly for American consumers if the Mexican trucks can travel in the US.

President Bush had threatened to veto spending bills which exceeded budget limits the Administration had put on domestic programs. 

The transportation spending bill included highway projects, grants for airport ixpansion and community centers, housing projects and economic development projects.  In part, the Bush Administration proposed cutting $765 million from the $3.5 billion budget for airport improvement grants.

Teamsters General President James Hoffa praised the Senate vote, calling the Bush Administration's action opening the border to Mexican trucks "illegal" and "reckless."  He commented, "We don't want to share our highways with dangerous trucks from Mexico."  Hoffa said that since the congressional action only blocks funding for a year, the Teamsters will continue to fight against the program. 
In his comments, issued September 11th, Hoffa linked the issue to the 9/11 terror attacks saying, "I'm sure every American is relieved that the Senate voted to make sure that potential threats to national security aren't allowed to travel freely on our highways."