In 1993, when the North American Free Trade Agreement was approved, the Mexican border was supposed to become similar to the Canadian border, where trucks are allowed to motor back and forth with just a simple weigh-in and a check of paperwork.
In 1995, the Clinton administration, under pressure from trucker unions, delayed the relaxation of that border regulation, citing highway safety concerns.
Rob Black, a spokesman for the International Brotherhood of Teamsters, said Friday those concerns are still valid.
"The drivers are not trained, the trucks are not safe and drugs are an issue as well," Black said.
In 1998, the Mexican government sued the United States under the provisions written into NAFTA to settle disputes.
Around the same time Mexico developed a database to track Mexican truck drivers and their cargo.
The border was supposed to be opened to Mexican trucks in January 2000 once all those services came online.