That's taking the idea to absurd extreme. You don't flip-flop the law every day. London for example has a congestion zone around the main city, which involves multiple limits and in many places removed congestion. This doesn't mean those areas are free for all again - the zone remains to keep out / reduce the congestion which would otherwise come back.

In my defense, the OP said "banning cars." In London to deal with congestion they basically just turn large sections of the city into a toll road. That's pretty different than "banning cars"

That's true, but whether banning cars or making it less attractive to cars (e.g. with London's congestion charge), the point is that places already have people working on road planning/etc., it can be done with humans making decisions, not a piece of code going "if (congested) {ban cars} else {allow cars}".

To use Oxford as a small example of more than a toll, there's a few roads in the city centre that only buses/taxis are allowed to use, and a few roads that only pedestrians can use (with some time-specific exceptions for loading/unloading/etc.). Nobody looks at it and thinks "well now it's not congested we should allow cars again".

> If cars are banned on a road then it won't be congested anymore, so cars will be allowed on it, then it will get congested so cars get banned

Some roads are congested even with private cars banned (e.g. Oxford Street).

> in the end I think what you're suggesting is running around giving tickets to people in traffic jams.

Would that be such a bad thing? Obv. it would need to be a little more formalized than that.

You don't work in a city with shitty traffic and public transport systems, then. I live in D.C.

If I were to take public transportation to my job it would take about twice as long and involve me walking 5 miles both ways. And I get in traffic jams daily.

So yeah, if you went around penalizing people for something largely outside their ability to control, there would be riots in the streets.

You put public transport instead. At least on some city centers this is already happening.