The game actually culls cars by default, and instead of parking they put their cars into their void pockets. There's mods that can disable both of those aspects, but that would mean you'd have to do some real traffic engineering. But then again, the game just lacks proper alternatives, especially decent bike lanes or walkable / car free neighorhoods, like mixed zoning or pedestrian zones, since everything needs to be separated and tied to a proper road. Would be cool if the game itself would feature a road designer where you can add different type of lanes, trams, greenery, parking spots etc. all by yourself and use that as a template instead of the predefined road types.