| I think this covers a lot of good points and I'm happy to see it, but the final section seems like a just-so. I've wondered if the difference in bike-induced-demand=good;cars=bad follows these lines: - Roads/cars often leads to the phenomena of something like grid-lock. A network might be able to throughput 100 cars a minute when only <=100 cars are trying to get through, but try 101 and it starts dropping: If 120 cars attempt passage at once, congestion actually causes the throughput to drop to like 80 (think of those backward-propagating traffic-wave videos). If 150, throughput drops to 70 etc. - You can add more roads/highways but if it doesn't address certain chokepoints, that throughput will still start descending at some point (though maybe a bit higher now like 110 cars/minute). - Sometimes you can address the chokepoints, but after some expansion the remaining chokepoints are essentially having the buildings and city intersections themselves, at which point you can only address the bottleneck by rebuilding buildings further apart, which leads to a cycle of worsening pedestrian access, local-depopulation, and more cars. - And then finally, maybe bikes are different in that they are small and agile with a congestion-failure-mode of being walked. It's hard or unlikely to get to a bike usage level that would lead you to want to move buildings very far apart to support them. - Or maybe bikes are just simply so small that the preferred distance between buildings anyway (for sun light, privacy) can support most realistic biking numbers (which would be limited by density limits anyways: elevators only practically go so high, commuting biking trips can only be so far). - Ultimately I wish there as a bit more explained here, maybe by someone that designs traffic/city simulations if that's how the best cost/benefits are tested now. It's really confusing that urban planning advocates concentrate on the un-improving car-trip-time/congestion KPIs like it's a dunk when it really seems some throughput-capacity utility metric would be more important. |