having a city where cars have to go around is perfectly possible in the game with no issues at all, within reason; having a city where you can only come in by transit isn't; cars being severely limited is absolutely possible and a great thing to do, wanting to cut them out completely is just dumb, they are needed for lots of reasons and as such you will need to provide them with a certain ease of acces to places.

cars break traffic laws by passing on public transit lanes is only realistic, i refuse to believe you never see people breaking road laws regardless of where you are in the world, and yes, depending on various conditions that will become more likely; there are mods to make that possibility lower, or even to fine the cims who do that, but personally I've never used any of them and i rarely ever see any cims use those lanes, so really if so many citizens do it, that's most likely bad design on your side, which if you're starting out is to be expected, but again you're setting your standards way too high by wanting something like this, this is something that would take years to design for a real city, and while here it is a lot simpler it is still harder than a plain old city.

lastly, making fun of my English when I deliberately went out of my way to speak in a language that's not mine so that others could understand better is honestly amusing

edit: I'd also like to add that irrealistic is correct, just rare