Diesels?
I have to pull the kill handle on my tractor to get the danged thing to stop running. And, even then, it fights on for a while... '-)
TXnMA

Shouldn't take more than one or two .50BMG rounds into the block to make ANY engine quit.
Only collateral damage would be forcing the driver to change his drawers in public after that deal.
I'd bet a half dozen snipers with Barretts could turn five miles of highway into a scrapyard in minutes, then if that mob said they were walking to the US they could back up their talk with some walkin'.