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> You assert this like it's a fact. But it seems like something that could be proven wrong. I don't see any real fundamental obstacles here. I think it's just

> You assert this like it's a fact. But it seems like something that could be proven wrong. I don't see any real fundamental obstacles here. I think it's just a safe conclusion based on some reasonable assumptions. Just to pick one as an example, Wiki tells me a NY subway train is usually 8 to 10 cars. I'll use 10 to make the math easier. They're between 15m to 23m long so I'll go with 20 and that's 200m. Capacity is around 200 people each which gives us 2000 people per train. A model Y is 4.7m long and can seat up to 4 people. To get to 2000 people capacity you then need 500 model Y. 500 Model Y, one after the other in a straight line is 2350m so already to get to the same capacity you need 10x the space without even factoring in the fact you need to add space in beteen each and every one of those 500 cars as a safety measure.

jillesvangurp 2y ago
The only reason it's interesting to share farts and bad breath with that many people is that subway tunnels in NY are really expensive to make. They cost many billions to dig and even minor extensions to existing tunnels seem to to turn into multi billion$ projects. And then you need these massive subway stations that also cost billions. Doing things at that scale seems really expensive and ripe for disruption. Your assumption is that there would be just 1 tunnel instead of many. Probably because you are assuming tunnels are super expensive and that that is something that cannot improved. The premise of the Boring company was that they would be able to cut cost by some orders of magnitude by doing things at scale. They haven't yet, obviously. But that doesn't prove the basic premise wrong. Cheap tunnels mean you could have many more tunnels between many more destinations; not all of which need to be super dense cities like New York. Which means you don't have to squeeze millions of people through a single one of them. The cheaper the tunnels, the less the capacity matters. Just add tunnels to scale if things get congested. And of course the model Y is hardly the final answer in pod design. There's no good reason why we can't have a mix of smaller and bigger ones. In fact, using a big lump of an SUV designed for road traffic for this seems not very optimal.
Veedrac 2y ago
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.
cornholio 2y ago
At a 2 seconds clearance between vehicles, the Tesla system at peak capacity of 4 passengers will move 2 people per second. So it's equivalent with a subway train at crush capacity running every 1000 seconds or 16 minutes. That kind of frequency is typical for some longer haul train links, airport trains with underground sections like the RER etc. Of course, there are other factors that preclude running Loop at 2s frequency, like station capacity and ensuing bottlenecks on ramps etc., but bear in mind there is no comparison between a train filled at crush capacity, with most people standing and smelling someone else's armpit, that you have to wait for a quarter of an hour, vs a leather seated car that takes you point to point to your destination without stopping at any intermediary station. The point is, they are very different systems that don't compete against each other. If you need a subway and have the money for a subway, by all means, build a subway. Loop competes with light rail, and it says it can do better than most of the light rail systems in operation, at least in the US. Both its claimed pphpd and per mile cost are sufficient to be financially competitive, to the point that it can attract private capital and generate profits. And the pphpd they demonstrated, of nearly 5000, was achieved with Tesla cars. If they manage to introduce 8-12 seaters and cracks self driving in the tunnels (a much simpler problem then full on road self driving) than it could compete with many of the less congested subway networks. It seems very irrational not to let them demonstrate what they claim, as long as they are using their own money. It's transport capacity that does not compete with other transit options and does not capture significant urban real estate.
- eesmith 2y ago
  > the Tesla system at peak capacity of 4 passengers will move 2 people per second. Your analysis is incomplete. A moving sidewalk on the airport can move far more than 2 people per second, and needs no driver. Where is the call to revive that form of travel descried in Heinlein's "The Roads Must Roll" and Asimov's "The Caves of Steel"? You are missing speed, and acceleration, and load time. > So it's equivalent with a subway train at crush capacity running every 1000 seconds or 16 minutes. Well-frequented London lines run with something like 2-3 minute intervals, not 16 minute intervals. And you can easily carry luggage with you, push a stroller, or roll your wheelchair on in. > and smelling someone else's armpit Yes, it appeals to rich people who want to use their money to avoid even minor irritations, and don't want to pay taxes to support mass transit that helps everyone. (From the link, "some press and discussion around the Loop figures it as more of a luxury option: something that casinos can comp for high rollers, that will spare people dealing with the general disaster of getting around the strip".) But that means having an alternative for us poor stinking masses. The Loop is not that solution. By the time the subway system gets to the crowd level you describe, a Loop-type system would be well over capacity. You'll be stuck in a line waiting for the next Tesla to arrive, surrounded by stinky people. > was achieved with Tesla cars. If they manage to introduce 8-12 seaters Why are they using Teslas? As the article notes, "due to their larger seating capacity and faster boarding/deboarding, the Loop would likely achieve a higher capacity if they just shifted operations entirely to the Club Cars". With "four rows of seats", it's likely something like https://www.clubcar.com/en-us/commercial/transport/villager-8 https://www.clubcar.com/en-us/commercial/transport/villager-... which says "A long time classic on resorts, the Villager 8 moves up to eight passengers in a single trip and can replace expensive vans. Yet it also travels narrow areas not accessible to conventional vehicles." It seems they could easily increase capacity now by simply changing vehicle type. Also, since the capacity numbers were achieved with Tesla cars, that means it excluded the GEM carts which the article says is uses for people with wheelchairs. That suggests the "nearly 5000" number does not include people with mobility issues, which would need to be supported under ADA requirements. At peak capacity, even a small disturbance can greatly reduce flow. > It seems very irrational not to let them demonstrate what they claim The page says their claim is that the fully expanded system will target only 90k passengers per day. It seems very irrational to not draw conclusions from that.

jillesvangurp 2y ago

The only reason it's interesting to share farts and bad breath with that many people is that subway tunnels in NY are really expensive to make. They cost many billions to dig and even minor extensions to existing tunnels seem to to turn into multi billion$ projects. And then you need these massive subway stations that also cost billions. Doing things at that scale seems really expensive and ripe for disruption. Your assumption is that there would be just 1 tunnel instead of many. Probably because you are assuming tunnels are super expensive and that that is something that cannot improved. The premise of the Boring company was that they would be able to cut cost by some orders of magnitude by doing things at scale. They haven't yet, obviously. But that doesn't prove the basic premise wrong. Cheap tunnels mean you could have many more tunnels between many more destinations; not all of which need to be super dense cities like New York. Which means you don't have to squeeze millions of people through a single one of them. The cheaper the tunnels, the less the capacity matters. Just add tunnels to scale if things get congested. And of course the model Y is hardly the final answer in pod design. There's no good reason why we can't have a mix of smaller and bigger ones. In fact, using a big lump of an SUV designed for road traffic for this seems not very optimal.

Veedrac 2y ago

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.

cornholio 2y ago

At a 2 seconds clearance between vehicles, the Tesla system at peak capacity of 4 passengers will move 2 people per second. So it's equivalent with a subway train at crush capacity running every 1000 seconds or 16 minutes. That kind of frequency is typical for some longer haul train links, airport trains with underground sections like the RER etc. Of course, there are other factors that preclude running Loop at 2s frequency, like station capacity and ensuing bottlenecks on ramps etc., but bear in mind there is no comparison between a train filled at crush capacity, with most people standing and smelling someone else's armpit, that you have to wait for a quarter of an hour, vs a leather seated car that takes you point to point to your destination without stopping at any intermediary station. The point is, they are very different systems that don't compete against each other. If you need a subway and have the money for a subway, by all means, build a subway. Loop competes with light rail, and it says it can do better than most of the light rail systems in operation, at least in the US. Both its claimed pphpd and per mile cost are sufficient to be financially competitive, to the point that it can attract private capital and generate profits. And the pphpd they demonstrated, of nearly 5000, was achieved with Tesla cars. If they manage to introduce 8-12 seaters and cracks self driving in the tunnels (a much simpler problem then full on road self driving) than it could compete with many of the less congested subway networks. It seems very irrational not to let them demonstrate what they claim, as long as they are using their own money. It's transport capacity that does not compete with other transit options and does not capture significant urban real estate.

eesmith 2y ago
> the Tesla system at peak capacity of 4 passengers will move 2 people per second. Your analysis is incomplete. A moving sidewalk on the airport can move far more than 2 people per second, and needs no driver. Where is the call to revive that form of travel descried in Heinlein's "The Roads Must Roll" and Asimov's "The Caves of Steel"? You are missing speed, and acceleration, and load time. > So it's equivalent with a subway train at crush capacity running every 1000 seconds or 16 minutes. Well-frequented London lines run with something like 2-3 minute intervals, not 16 minute intervals. And you can easily carry luggage with you, push a stroller, or roll your wheelchair on in. > and smelling someone else's armpit Yes, it appeals to rich people who want to use their money to avoid even minor irritations, and don't want to pay taxes to support mass transit that helps everyone. (From the link, "some press and discussion around the Loop figures it as more of a luxury option: something that casinos can comp for high rollers, that will spare people dealing with the general disaster of getting around the strip".) But that means having an alternative for us poor stinking masses. The Loop is not that solution. By the time the subway system gets to the crowd level you describe, a Loop-type system would be well over capacity. You'll be stuck in a line waiting for the next Tesla to arrive, surrounded by stinky people. > was achieved with Tesla cars. If they manage to introduce 8-12 seaters Why are they using Teslas? As the article notes, "due to their larger seating capacity and faster boarding/deboarding, the Loop would likely achieve a higher capacity if they just shifted operations entirely to the Club Cars". With "four rows of seats", it's likely something like https://www.clubcar.com/en-us/commercial/transport/villager-8 https://www.clubcar.com/en-us/commercial/transport/villager-... which says "A long time classic on resorts, the Villager 8 moves up to eight passengers in a single trip and can replace expensive vans. Yet it also travels narrow areas not accessible to conventional vehicles." It seems they could easily increase capacity now by simply changing vehicle type. Also, since the capacity numbers were achieved with Tesla cars, that means it excluded the GEM carts which the article says is uses for people with wheelchairs. That suggests the "nearly 5000" number does not include people with mobility issues, which would need to be supported under ADA requirements. At peak capacity, even a small disturbance can greatly reduce flow. > It seems very irrational not to let them demonstrate what they claim The page says their claim is that the fully expanded system will target only 90k passengers per day. It seems very irrational to not draw conclusions from that.