In the most common scenario, Mexican shipping companies move goods to a border city — Mexicali, for instance.
They then ship the goods over the border with mid-size rigs to U.S. "drop yards" within the zone, where the trailers full of goods are interchanged with American rigs and shipped to points throughout the country, according to Calexico customhouse broker Bill Polkinhorn.
This flow of the mostly diesel trucks to and from Calexico drop yards affects local road conditions, traffic and air quality.
The U.S. Environmental Protection Agency reported more than 1,000 trucks a day rumble through Calexico and surrounding areas in the commercial zone.
Some trucks in that number are the shuttle trucks (mid-size tractor-trailer rigs), that can make three or four trips across the border in a day.
At the recent budget workshop, Mayor Pro Tem John Renison singled out the worsening condition of Cole Road as one of his "top priorities" of the upcoming fiscal year.
Cole Road is used by truckers and Mexican tourists coming from the Calexico East Port of Entry. It has numerous potholes and fissures because it wasn't designed for the stress of so much traffic.
Other roads that feed off Highway 98 toward Highway 111 or Interstate 8 suffer similar fates. Those roads include Heber Road, Barbara Worth Road (parts of which are closed for repairs), Jasper Road and Anderholt Road.
The EPA has labeled certain local intersections, including the Cole and Bowker roads intersection, as "hazardous" because some of the trucks carry hazardous materials and pose considerable danger if involved in an accident.
If the U.S. Department of Transportation had been allowed to enact the recommendations of President George W. Bush's administration, some effects of truck traffic might be reduced, said Steve Birdsall, county air pollution control officer.
"There could be a reduction in emissions if the trucks weren't required to go back and forth in that zone," Birdsall said.
Bush administration plans would have allowed the trucks to motor around Calexico and head straight for their destinations.
But some Mexican shipping companies would stick with the back-and-forth border zone shuttle system that makes Calexico itself the "destination," said Polkinhorn.
He said if the Bush administration allows Mexican trucks to legally travel on U.S. highways, it would have little to no effect because the trucking companies that want to bypass the zone regulations find ways to do so.
"It would be a very low percentage of carriers who took advantage of the proposed changes," Polkinhorn said.
According to the North American Free Trade Agreement, Mexican trucks should have been granted full access to American roads in January 2000, but the Clinton administration, citing safety concerns and under union pressure, blocked that provision of the treaty, according to The Associated Press.
At the Wednesday morning White House press briefing, Bush Press Secretary Ari Fleischer said the president believes strongly what the House did Tuesday was wrong.
"The House action had nothing to do with safety. It has to do with banning trucks because they happen to be operated by our friends to the south," Fleischer said.
He added, "The president thinks that's wrong."
A reporter asked if the House's action, if not done for safety reasons, could be construed as racist.
"The House action was not tied to safety; in fact, the House action went in the opposite direction on safety by striking the president's request to more than double the number of inspectors," Fleischer said.
Citing the number of Republicans who voted for blocking the trucks, a reporter asked Fleischer if the president is losing ground with his own party.
"No, I think you're seeing a president who has, frankly, been very successful on legislative matters," Fleischer said.
Hunter's press secretary, Mike Harrison, said the issue for Hunter is infrastructure.
"In the Imperial Valley we lack the infrastructure to support the amount of traffic that has resulted from NAFTA," he said.
He added, "When you allow trucks to come through that are unsafe it only compounds the problem."
At the briefing Fleischer addressed concerns about the safety of Mexican trucks.
"Under the rules as announced by President Bush's DOT, all trucks are subject to the same safety requirements," he said.
Polkinhorn said not only are the trucks held to the same standard, sometimes they are safer than trucks operating on U.S. highways.
"They (Mexican trucks) are subject to a much higher degree of safety than most trucks that are running around," Polkinhorn said.
He added, "In Los Angeles there are thousands of trucks that never cross (inspection) scales. The trucks that cross the border here are checked every time they go through."
Staff Writer Aaron Claverie can be reached at 337-3419.