However, all of us drivers have far too much life experience with driving behind/around giant bus and semi trucks that lay down a choking smokescreen.
Like it or not, diesels in America have a history of laying down choking smokescreens. Lack of regulation, lack of inspection, who knows.
Possibly new diesels or car diesels aren't as toxic. If you want to sell diesels to Americans you need to wait for them to forget about the last time they were "gassed" because they were nearby a bus or truck exhaust.
The other problem, living in a northern climate where diesel gels in the winter, its a huge hassle for the few diesel owners we actually have. And as if starting a gasoline engine at -15F isn't enough of a struggle, consider the poor diesel owner. They could sell well in Miami or New Orleans without the fuel issues, but inevitably someones going to move up north and the trash talking will commence. With extensive maintenance, expensive maintenance, they can be almost as reliable in the cold as a gasoline engine... almost. Why not save the extra maint money and buy a cheaper lighter higher powered gas engine? I have no question that the net gain to the environment tilts on the side of diesel in Louisiana, and it Might even net be cheaper. In the north... I strongly suspect the net overall system environmental costs of gas are significantly lower, as is the total system wide cost.