More buses and bus routes, smaller cars and eventually a move to electric vehicles. That doesn't need new infrastructure, just a different mindset.
Toronto for example developed in the same way as many US cities, but they've embraced buses and aren't as reliant on cars in the same way as Americans in similar cities.
They have been trying the whole bus thing in Cities all over the US with minimal success. Mainly due to everything being so spread out.
Like in Houston and Dallas, you want to take to bus to work but you live in the suburbs? That's a good 2 hour route and you need to be at the bus station at 430am. Also, you need to drive your car to the bus station.
The way highways are built do not include the necessary alignments for buses. And the way cities are built do not make it something that is better. That's the problem, Americans don't want to have to sacrifice their ability to be mobile. Going to work, picking up kids from school, etc. What if you have to work late? Buses stop at 8pm in certain areas.
I've been involved with urban planning early in my career. This cannot be solved retroactively.
It has to be a new set of standards moving forward. Of course, there are a handful of places it has worked, that's the case with anything.
I do agree that moving to smaller cars and EV is a good idea, but not right now. We still don't have the grid for it. And European countries have always been this way. So that's not really a basis for anything.
There has not been one city in the US that has successfully done this and there is a reason for that. It's not just the American mentality, it's simple logistics. All our big cities are so spread out it's insane.
The way our government will force this upon us, is to raise prices so high that people cannot afford to drive anymore. That's what happened in Europe and it worked pretty well. If it was cheaper and easier to drive in Germany/Denmark, you would see more people driving. But the countries were setup against it and most people are forced to travel the way they do, not by choice. When i lived in Germany every single person wanted to own a car and drive, have the independence, but they couldn't afford it.