alt Hacker Newsusually at the expense of one or the other, usually cars.
FWIW I think that is a fine trade-off. I think people don’t truly realise how poorly cars scale until they take a really large step back and take a holistic view on infrastructure- which is inherently difficult for most people as they are so close and bought-in that they can’t even conceive of life being different than what they’re used to.
And they reach for exceptions to prove the requirement, when less cars in cities frees up the roads for those that truly need it (LGV and disabled access, but slow thus disincentivised unless actually required and thus less likely to cause accidents).
It's not necessarily at the expense of cars; the people riding bicycles on the bike lane are no longer driving cars blocking the way ahead of you, and parking their car in your favourite spot. Since bicycles use space more efficiently than cars, this can actually be a win for both the cyclists and the remaining drivers (who now have one less lane, but even less traffic). However this only happens if cycling adoption is high enough, which is why the bike routes have to be well connected.
Sometimes it doesn't even require sacrificing a lane, because many North American cities have lanes that are wildly larger than necessary or even appropriate given the posted speed limits. The lanes can simply be narrowed, and then this also causes the drivers to naturally drive at safer speeds, reducing traffic accidents, speeding tickets, and the unplanned delays that those both cause.