This (specifically car/bike traffic) may be the first real-life example of a Giffen Good I've come across: https://en.wikipedia.org/wiki/Giffen_good

You'd think that people avoiding public transport would result in increased car traffic. But in a scenario where the roads were already at or near capacity, that's impossible. Not only would a number equivalent to those switching from public transport have to use bikes. Because bikes also need (some, but less) space on the roads, car traffic actually needs to decrease.