I'm aware we're technically strict, but I don't see the EPA shutting down roll coal culture any time soon. It took us this long to catch Cummins[1] after VW got dragged through the courts. At this point I find it hard to believe any diesel motor truly passes US emission standards.
[1]https://cleantechnica.com/2023/12/27/cummins-fined-1-67-bill...