Note https://www.congress.gov/bill/118th-congress/house-bill/2436 - this would reclassify it from a civil to a criminal offense, but did not pass into law.

I stand corrected, thanks.

You should note that nobody calls the people who put them there 'illegal drivers'. (We also don't apply that moniker to people speeding, failing to signal on a lane change, or being responsible for many other moving violations. We do apply it to people driving drunk or without a license - which are criminal offenses.)

Nobody calls them "illegal" drivers because there's a more specific term, specifically "driver who parked illegally" or "speeder". The latter already incorporates an implication if illegality, and the former is basically the same as "illegal driver" but with slightly different phrasing. The equivalent for immigrants would be "person who immigrated illegally", but that's basically the same as "illegal immigrant". I suppose you can try to use the latter term as an attempt to destigmatize the term, but that feels like the whole "autism vs people with autism" thing from a few years ago all over again.