Maybe introduce a gradual shift instead over 50 years or so: with each next year taking the originally expected profits of public transport and gradually add those as taxes for cars while at the same time also reducing the current public transport ticket prices?
At the end of those 50 years public transportation could be free and the stubborn car owners or businesses would simply help subsidize more efficient ways of transportation.
Maybe allow reduced taxes for electric vehicles at the same time.
In the end, it wouldn't be much different than the subsidized meat production with artificially lowered meat prices in the US, nor would anyone care much about small increases like that on a year by year basis.
Private individuals are becoming less and less able to afford cars in the first place (not even talking about real estate). If legislation around predatory lending schemes would be tightened, the demand for cars would decrease.
If at the same time you'd invest aggressively in actually making sure that there is enough public transportation in place (as is the case in many European countries already but not the US), then it'd help with displacing them in the background as well.
Couple that with a remote working culture, a few decades of employee pushback and quitting their jobs if they're asked to return to the office in careers where that's not necessary, better postal services and ride sharing apps, food delivery apps or a push for cooking meals at home and you'd see even more significant changes. Even more so if the road networks and infrastructure cannot support rush hour traffic with most of society living in a single shift mode, rather than morning and afternoon shifts.
In contrast, if any initiative comes out today that calls for immediate and drastic change, it will get shot down. Real change takes a lot of patience and dozens if not hundreds of compounding factors over decades.
Either that or going out into the streets with guns in hand, but that has historically worked out horribly time and time again and humanity should be past that savagery. Protests could happen, of course, since that's a bit different.
Regardless, with more initiatives to limit heavy industry, global shipping of goods that could be locally manufactured and an overall push for less consumerist lifestyles, humanity might even have a few hundred years left to kick around on this rock before the long term environmental consequences actually start becoming visible!
At the end of those 50 years public transportation could be free and the stubborn car owners or businesses would simply help subsidize more efficient ways of transportation.
Maybe allow reduced taxes for electric vehicles at the same time.
In the end, it wouldn't be much different than the subsidized meat production with artificially lowered meat prices in the US, nor would anyone care much about small increases like that on a year by year basis.