here's a question that probably only has one dumb answer (because the govt said so) but I'll ask it anyway

Why is it that the vehicles the govt will not allow Americans to buy and drive (they don't pass crash standards, safety standards) whatever the issues are that prevent Eurospec cars, and cars only sold in Mexico and South America, from being available for American citizens and consumers to purchase and drive and in the USA. (Examples, Buick Century SS, VW Crossfox, Nissan March, Ramirez R-15, Cajoma, Pena, Mago, Tractocasa

Why is it the trucking industry in Mexico is allowed to drive semis that burn fuels that are less expensive and create more smog, with out DEF on diesel engines, and I'm guessing, without catalytic converters, without the crash testing the US DOT requires, etc etc. 

See where this is going? In the USA, the vehicles the govt will allow to be sold, cost more, and must pass crash testing, and smog certs, and we can't import the cars from Mexico... but those cars can drive across the border and into the USA, and those trucking companies that buy and operate less expensive semis in Mexico are allowed to operate in the USA. 

I'm wondering why we Americans can't go into Mexico, buy some cheap car, and bring it back into the USA and drive it as a commuter, when someone in Mexico can. 

Oh, and this ain't racist, but the USA and Mexico have a very long border, with many border crossings, and different smog and crash standards, but Canada has the same as American. So, since we don't have borders with other countries, and the Eurospec stuff ain't allowed to get imported unless you're a billionaire (Jerry Seinfeld and his Porsches) I'm not discussing those because they can't drive into the USA.

Can American companies buy Mexican trucking companies and bring their fleet into the USA and operate it? Or, can only Mexican trucking companies operate in the USA? 

So, I'm also ready with a solution, the vehicles get registered, and smogged, in the USA, and are only allowed to cross into the USA with an American state registration, insurance, and smog test. 

That makes sense, and there's legal precedent, truckers used to be required to have a license plate from every state they did business in, am I right?