3 ms·

Note that 2350m is 6 minute headway at a 17mph average subway speed, which isn't at all crazy for a subway. A single-tunnel Boring Loop isn't competing against

Note that 2350m is 6 minute headway at a 17mph average subway speed, which isn't at all crazy for a subway. A single-tunnel Boring Loop isn't competing against the 10th busiest subway, though. Even if Boring Loop were competing against New York City Subway, at $2.5B/mi you could build something like 50 parallel lanes at the same cost, and 2350m/50 is only ~50m. Space them out a bit so it's actually driveable and you're probably still ahead with Boring Loop, even assuming the trains are running full (which is not default). Now, if you did invest enough for 50 parallel lanes you clearly wouldn't want to do 50 parallel lanes; they pack awkwardly, don't make sense to centralize that much if you design doesn't force you to, and you go from having a regulatory advantage of being able to build under city roads to a regulatory nightmare of asking to build 50 parallel lanes underground. It makes much more sense to build point-to-point connections out like a road network, and bring in more traditional mass transit where you have particularly busy connections that can't be handled with a reasonable number of lanes.

manuelmoreale 2y ago
2350 is just the length of the cars one next to each other without factoring in any distance you obviously need to have between each car for safety. Stopping distance at 40mph is apparently around 20m (without human reaction time) With reaction time included is about double. So you need at least another extra 40m between each car. There’s 499 gaps between those 500 cars so that gives you an extra 20km. So your “train” of Model Y need roughly 23.5km worth of tunnel to move 2000 people. Doesn’t look very efficient if you ask me.
- rrnechmech 2y ago
  Fascinating to think about if and when FSD is perfected (or heaven forbid before) what a world with cars moving about with near zero reaction time would look like. That is to say, completely removing reaction time out of the equation at scale
  - manuelmoreale 2y ago
    It would cut some space for sure but you still need space in between no matter what. You also need to factor in space because these cars have to stop, people have to move in and out of them and that takes time.
- Veedrac 2y ago
  Yes I mentioned spacing them out, it doesn't change the point.

manuelmoreale 2y ago

2350 is just the length of the cars one next to each other without factoring in any distance you obviously need to have between each car for safety. Stopping distance at 40mph is apparently around 20m (without human reaction time) With reaction time included is about double. So you need at least another extra 40m between each car. There’s 499 gaps between those 500 cars so that gives you an extra 20km. So your “train” of Model Y need roughly 23.5km worth of tunnel to move 2000 people. Doesn’t look very efficient if you ask me.

rrnechmech 2y ago
Fascinating to think about if and when FSD is perfected (or heaven forbid before) what a world with cars moving about with near zero reaction time would look like. That is to say, completely removing reaction time out of the equation at scale
- manuelmoreale 2y ago
  It would cut some space for sure but you still need space in between no matter what. You also need to factor in space because these cars have to stop, people have to move in and out of them and that takes time.
Veedrac 2y ago
Yes I mentioned spacing them out, it doesn't change the point.