The latest EU diesel standards for passenger cars are actually on par with the gasoline standards. Don't know what the standards are for heavy trucks though.
Can we trust any of the big automotive manufacturers to actually meet those standards without cheating?
Look at how widespread the issue is [Dieselgate](https://www.cleanenergywire.org/factsheets/dieselgate-timeli...)
https://www.forbes.com/sites/davekeating/2018/07/26/carmaker...
> The automotive industry says it has cleaned up its act. But this week the European Union’s executive branch, the European Commission, revealed it has discovered a whole new form of cheating – this time on CO2 emission tests. The 2016 scandal concerned air pollution tests on diesel vehicles, where automakers were using so-called ‘defeat devices’ during tests to make the cars seem like they were emitting less pollution. Now, the carmakers are accused of doing the opposite – artificially inflating the level of carbon emissions produced by new cars coming onto the market now. Why would automakers want their cars to look more emissions-intensive than they are? Because a new EU law will require automakers to reduce their fleet average CO2 emissions by 15% by 2025 and 30% by 2030 – based on 2021 levels.
I know this is anecdata, but at least in CO, UT, WY area there are more modified trucks than what is immediately apparent, since often a truck w/ bypassed emissions equipment isn't heavily cosmetically modified.
And, I'm sad to say, some folks just like the whole "rolling coal" thing and the ability to put out huge plumes of black smoke.
There are a fair amount of people who will actively pollute because you asked/told them not to, and I wonder if they have a significant effect on the environment