Pemex Diesel Fuel Update

ED: There are no USA trucks travelling south in Mexico. Once in awhile there are some specialized low boys and similar trailers carrying a large tank or some other huge piece that originated in the USA. But rare. Usually a Mexican truck picks up the trailer at the border. Have you ever seen a US plated Class 8 truck deep into Mexico? Not a truck with plates from both countries. Just USA! There also may be some smaller trucks such as media satellite trucks. I do not know what happens when the NASCAR trucks get to the border. Do they switch tractors or use the USA truck? But none of the above would cause Pemex to have that fuel everywhere. I doubt any large carrier ( Swift,Werner,etc.) would take a chance on using fuel that is either LSD or contaminated with LSD. Many of the US carriers are either partnered with a Mexican firm or they simply bought a Mexican company. They have huge yards on the US side of the border and either cross dock the goods or drop the US trailer for a Mexican tractor.