Car-Free Urban Design

City planners could just make narrower streets (like 1-way alley kind of narrow). No need to ban cars, instead design the streets so other modes of transport are more convenient.As a bonus the land you would have used for wider streets can be used for something better.

Actually you need people in the city to not depend on cars. Public transport, cycle lanes and a reason to stay in the city centre like good restaurants, cafes, some festivals. Just closing a street to cars might just make everyone drive around and miss it. Also don‘t let big shopping malls be build at the outside of the city with huge parking areas. Create parks instead.

People don't have to be in cars, and most cities have way more people in cars than necessary.

put the cars underground, not the pedestrians. let the cars go fast and let the people stroll in the sunshine.

Which is the whole point of designing cities so cars are not needed

Designing cities for car is a huge mistake!

Agreed on the shared roads, but in cities it is better to put the cars on pillars. Removing cars from roads does wonders and makes neighborhoods look much nicer. Instead of the pillars you can remove cars from most roads and have limited one-way roads that are fast and without traffic lights. The cars can park in a parking garage and continue on foot/bike/tram. I believe this is faster for the cars as well.

Car oriented cities are a bad idea.

Well, traffic doesn’t exist in a vacuum. One could engineer a system where this is less likely to happen, by simply engineering a system where people are less likely to drive. Many European cities are systematically reducing incentives to drive at all, by improving alternative means like public transport and biking, removing parking, narrowing or eliminating car lanes, and cutting off through streets for cars.

Not just bike lanes. Ban private car traffic from cities completely. Only allow private cars between cities.