Introduce a cheap alternative, get people used to it, then slowly phasing in taxes to make the undesired behavior too expensive to be worth it for the average person, but still give the option.

I have long thought that cars should largely not exist in cities, but (in America at least) they're required for rural living. Inside cities, there should be cheap (maybe even free), readily available, and numerous public transportation options. Convert parking lots into usable land, and install large parking garages on the outskirts of the cities, again cheap or free, and make them hubs for the public transportation options.

Now, people can drive to the city on their own. We don't have to immediately redo the entire country's infrastructure so that rural citizens still have mobility. If you're just passing through the city, or want to keep your car on you, there could be a day pass option. It'd be expensive, but doable. Otherwise, you can park and do whatever you need to, and just return to your car when done.

As far as city dwellers who may want to own a car for trips, allow rental of a space in a parking garage for a reasonable rate. You can store your car there indefinitely, have free access to it, but would still need a day pass to operate inside the city.

Change is slow. We have to accept some half measures in service of getting things more in line with where we want them. Eventually we may be able to phase out cars completely, but I'd personally be fine with a drastic reduction in cars inside cities. Incentivizing alternatives works better than punishing the unwanted behavior, and works even better when the two are used in tandem.

An even more highly infectious and dangerous pandemic.

I don't think there is a "best way" - but increasing costs is one way. Singapore is an example of this - you have pay up 106K SGD for the COE (certificate of entitlement) to even be allowed to own a car.

1. Tax carbon (and equivalents)
2. give back all carbon tax to all citizens, equally
3. Increase tax linearly over time, and let folks and business plan their transition predictably.

This will incentivize people to demand affordable transportation, transition to alternatives, get low income citizens a reason to not oppose increased cost of living. Big consumers have to pay, low consumers will pay a little but get more back.

Check out Citizens Climate Lobby.

I view it as sidelining cars to improve public transportation.

• First thing is to eliminate and revise public zoning laws and removing parking minimums. This causes change the slowest but is the most important to start since it will lead to denser population centers, and parking garages can be closer to residence.
• Second move I think is to eliminate extra lanes and trim road widths. This leads to driving being something that takes more focus and is slower. This also frees space for bike lanes and even dedicated bus lanes.
• Slowly phase out free parking across the city. Start with spots directly next to crosswalks so that there is better visibility of pedestrians crossing. Then focus on bus routes to free a dedicated lane when possible. This discourages driving since there's fewer chances you'll be able to park close to the place you are going.
• While this is occurring, you should be introducing public transit as it becomes feasible. More buses or trams, guarded bike lanes, etc.
• MAINTAIN YOUR PUBLIC TRANSIT!! As trains and buses fall into disrepair the number of people willing to ride it will drop off. Also keep the bike lanes and sidewalks clear and smooth.

That's what I've got. It takes decades to break down this infrastructure for new stuff. You also need the to be having accessibility in mind whenever you are thinking about installing public amenities or removing infrastructure.

By decentralizing them. We could have less cars if less people needed then by have a car librsry that is in walking range that people can use when they need instead of everyone having one/two/4 cars per nuclear families

Lately I've been pointing out that most drives people take regularly are only a mile or two long. It's a hit and miss argument though. Probably more useful for getting people on board with smaller, lighter, cars than getting them out of cars entirely.