I work part time for a truck driver. I can assure you that when he's sitting in Laredo, TX waiting for a load to haul up north, he has no desire to ever take a load from the US into Mexico.
The last time I was in Progresso the main road leading to the bridge needed paving. I don't think it has ever been paved.
I know John Cornyn would like the U.S. to build infrastructure (pave their roads) in Mexico. How bad are the roads in inner Mexico?