I think that frequently, a city will be so optimized for cars that (1) no other infrastructure can effectively work around it, and (2) any changes away from tha

I think that frequently, a city will be so optimized for cars that (1) no other infrastructure can effectively work around it, and (2) any changes away from that optimized solution feel aggressive toward cars. For example, consider curb radius at intersections. The smoother the curve, the nicer the experience for cars. If you can take the turn at 35 mph, then you don't even need to slow down. The car behind you doesn't need to slow down as you turn, and it's altogether more enjoyable to drive. But that means that the intersection is much larger, to accommodate the smoother turn. That means cars are making a right turn at higher speeds, leading to more dangerous collisions with pedestrians. And this happens for pretty much every tradeoff. That might be why you see it as an impasse between different groups, because either tradeoffs need to be made, or the overall cost goes up significantly (e.g. moving all parking spaces underground). * Bike lanes are adjacent to car traffic, decreasing usage. We could have separated bike lanes, but that space was already used for more car lanes. * Bike lanes take circuitous routes, increasing distance. We could have more direct routes, but that space was already used for wide roads. * There's no walkable area in the city center, because the shops have large set-backs, and are spaced far from each other. We could have storefronts closer together, but that wouldn't allow for as much parking space. * Bike parking is rare, and typically pretty far from your destination. We could have bike parking at every storefront, but that would require cars to be parked further away. (Though, given that you can fit 10-15 bicycles into a single car spot, the impact even there would be minimal.)