Not having to wait 55 minutes if you ever miss a train, or hoping a theoretical 15 minutes for a bus with a very high chance of skipping runs or breaking down. And a system to actually be where you want to be, instead of then having to walk multiple kilometers after reaching the central station.
A lot more public transportation ( tram, bus, brt, subway, depending on the budget), mixed zoning, pedestrian zones/streets, proper bike lanes, expensive parking inside the city, bike lease (like Vélib'in Paris), trains to facilitate transit between zones without good public transportation access (like suburbs or countryside) and city center.
Sorry, more public transport works only to an extent, many examples over the world. Germany, for example, makes it kinda hard and hurtfully expensive to even get a driver's license. Above 2000 Euro and at least a year in the cities. Many just give up. But that's not the way either. I for myself would simply forbid large SUV and other large vehicles in any denser populated areas, massively support the hydrogen and fuel cell technology, stop listening to the greedy mofos who tell everyone electric cars are the future, they are not in the current state of development, only for short distance deliveries. Movement of any goods on rails, small (electric, hydrogen) vehicles to the shops. More space for bicycles is a way, but it works only to an extent, too.
Edmonton Alberta wants to introduce a concept of a 15 minute city, where wherever you are in the city it will be a quick 15 minute walk to most of your daily needs
Don't let the conservatives hear you say that. They apparently think that "15-minute city" means "you can't travel more than 15 minutes from your house" or "you can only drive your car for 15 minutes a day" or some other such nonsense.
Oh here they just make it increasingly harder to use a car inside the city without a matching increase in public transportation offer and seemingly bank on everyone becoming a cyclist or using these dumb motorized scooters things.
And given how annoying certain cyclists can be (not all of them, but many are) that ain't looking good.
Same in my area. They introduce meters, take away free parking areas, lower the speed limits, ban left turns off main streets.
But they don't fix the sidewalks, they don't make a nice alcove for the bus stops, they have the trains but you need to pay a fortune to get to them in parking, they don't install bike lanes, they treat little paths in woods like suburban streets, and they don't have the crosswalks sorted.
I like how they made my street a one way street that changes way at each intersection, making it impossible to drive in straight lines.
They also keep demolishing ugly concrete roundabouts to then rebuild a similar, just as ugly, vegetation-less concrete roundabout.
The answer is well planned mass transit.
I have been to Tokyo. Took their bus, subway, and bullet train. They work flawlessly together connecting millions of people. I believe the public transit in Japan runs far more efficient than the ones in the US. They also are profitable unlike the one here swimming in debt.
Before Vietnamese Sai Gon was still called Sai Gon, there was a lot of car on road.
When Sai Gon change name to HCMC (i.e: communism triumph over greedy capitalism), lot of cars disappeared, replace by bycycle, then motorcycle until today.
So, porverty to the point that convert car from necessity to luxury is a best way to reduce car.
Improve rural connectivity to allow more people to work remotely from a non-urban/suburban area. Starlink is decent, but still not great for video calls.