6 ms·

I believe driver-less cities will eventually converge to networks of microvehicles like this, as opposed to large, inefficient vehicles designed to handle highw

by yholio 6y ago

I believe driver-less cities will eventually converge to networks of microvehicles like this, as opposed to large, inefficient vehicles designed to handle highway speeds and risks. You can fit two such pods side by side in one of the tunnels of the Boring Company. If they run at 2 second intervals, one after the other, with an average occupancy of 1.5 people, a single tunnel can provide a peak throughput of 90 people per minute or 5400 per hour. That's about half of what a subway can handle. You could also create "formations" of pods even more tightly packed for longer cross-city links. Full computer control requires much less safety devices such as airbags - like in a subway, the crash is ruled out by proper management of trafic. Outside the tunnels, they can blend in easily and provide a sane mass transport alternative, as opposed to congesting the city with more full sized cars. An existing row of paralel parking spots is all of a sudden a mass transport station where pods dock perpendicularly and await commuters; no need for fancy elevators, just an steep slope to the tunnels below.

ant6n 6y ago
We need mass transport, not utopian „mass transport alternatives“. Also, active transportation in general. Btw, using the same optimistic math, mass transit can do 90,000 pphd (2k ppl every 90s), in reality the max is around 40K.
- yholio 6y ago
  Well, you cannot pack trains of 2K people at 90 seconds, because you reach a limit with people getting in and off in the stations, the whole system slows down with trains waiting their turn to enter the station, so real throughput decreases drastically. Additionally, infrastructure costs are much higher for similar peak rates since subway tunnels remove 3x more dirt volume, and require proportional structural materials (7.3 m bore holes vs the current Borring prototypes of 4.2m) Also, there is a more fundamental problem with reaching high thoughtputs with mass transit: you need to force people out of optimal routes from their distributed destinations and origins, into enforced stations. This makes sense for point to point links like LA to SF, but it's very inefficient when trying to cover a 2D city: the more routes and stations you add, the less you are likely to reach peak capacity of any one link. If you are going for city-wide subway, you will pay much, much more to build large, expensive tunnels that will stay mostly idle at the perifery of the system.
  - lmm 6y ago
    > you reach a limit with people getting in and off in the stations, the whole system slows down with trains waiting their turn to enter the station, so real throughput decreases drastically. Yes, and this would be an even bigger problem for your proposal, that's the point. > Also, there is a more fundamental problem with reaching high thoughtputs with mass transit: you need to force people out of optimal routes from their distributed destinations and origins, into enforced stations. This makes sense for point to point links like LA to SF, but it's very inefficient when trying to cover a 2D city: the more routes and stations you add, the less you are likely to reach peak capacity of any one link. If you are going for city-wide subway, you will pay much, much more to build large, expensive tunnels that will stay mostly idle at the perifery of the system. You're hugely exaggerating the problem. You get some inefficiency yes - if we imagine a grid system then many journeys require a change of line and the average journey is 1.27x longer than an ideal path between two points, assuming people don't change their actions at all (e.g. living on the same line where they work). But that's outweighed by the efficiency gains of mass transit - in a city with a decent subway system that longer journey with a change will still be significantly faster than driving. As for tunnels sitting idle at the periphery of the system, in the real world that's really not the issue you make it out to be, for a number of reasons; housing concentrates along commuting corridors, the places where the population thins out are, by the same token, the places where land is cheap and the train line can run on the surface, and if necessary then trains can turn short or split/join. If you look at the usage levels that subways actually achieve, they're incredibly cheap for what they do.
    - yholio 6y ago
      >> trains waiting their turn to enter the station > Yes, and this would be an even bigger problem for your proposal, that's the point. No. Trains must make every station. A low occupancy pod will only diverge from the high speed lane when it has reached a destination or pickup point. > in a city with a decent subway system that longer journey with a change will still be significantly faster than driving. I don't think anyone disputes that. But this happens because there is no comparable point to point transit system and the existing road network is inefficient. The point of building tunnels is remove those conflict areas and provide direct point to point routes with very high throughput. If, for the same price you can have similar throughput using individual vehicles, then it makes absolutely no sense cram people into comunal transport, force them into unnecessary stops, changes, and waiting times, making them compete for real-estate prices in transit corridors etc.
qayxc 6y ago
> If they run at 2 second intervals, one after the other, [...], a single tunnel can provide a peak throughput of 90 people per minute or 5400 per hour. I like optimism in general, but think about that for just a second. At the vehicles' top speed of ~45km/h, 2 seconds translate to an average distance of just 25m. This leaves very little room for error and isn't enough of a safety margin. Then there's the obvious thing which renders this idea completely impractical: have you ever tried to stop a car going at 45km/h, get out of it and have another person enter the vehicle in well under 2 seconds? That's practically impossible. Also, it's time to rethink cities instead of regurgitating failed concepts (e.g. individual transport within densely populated areas) over and over again. A liveable city should be made for people, not cars (no matter the size). Going through the insane effort of stuffing individual traffic underground wouldn't change anything - you'd just have your congestion during peak hours underground; it wouldn't go away, though.
- yholio 6y ago
  The recommended spacing for human drivers is 3s, and if you ever drive on a highway, you will see 2s is the norm most drivers actually use at much higher speeds. There is absolutely no issue to reach that spacing for computer divers at 45 Km/h, even if the front vehicle comes to an instantaneous stop, 10 meters is enough to brake. Clearly the stopping and picking up of passengers is not gonna be done on the main lane. Just like with regular cars, pods exit the speed lane, enter a deceleration lane, then stop into the actual station - a series of parking spaces - where people can embark and disembark at will.
  - qayxc 6y ago
    How on earth would you have multiple lanes within a glorified utility tunnel? That's even more unrealistic, because now you not only need a main tunnel and emergency exits, you also need a bunch of parallel tunnels with individual lifts/ramps plus lots of room for merging. This is even more impractical. Just to be clear: impractical doesn't mean impossible - it just means that there's no way this can be as economical, safe, and efficient as existing concepts. An actual station or "a series of parking spaces" as you put it, has no advantages over a traditional subway/people mover station in terms of efficiency, cost and space requirements while offering significantly less throughput. I just don't see how any of this would be an improvement in any way.
rjkennedy98 6y ago
> You can fit two such pods side by side in one of the tunnels of the Boring Company Counting cars instead of people again. You should work for the department of transportation.
- yholio 6y ago
  Some pods will indeed travel empty in the system to rebalance the supply of vehicles into areas of rush hour exodus. But this is a highly predictable event; the pods will be supplied in advance and on less congested, roundabout routes. So it should have little bearing on peak capacity of any single link. At peak, the 1.5 occupancy rate I factored is achievable and quite typical for car commuting.

by yholio 6y ago

ant6n 6y ago

We need mass transport, not utopian „mass transport alternatives“. Also, active transportation in general. Btw, using the same optimistic math, mass transit can do 90,000 pphd (2k ppl every 90s), in reality the max is around 40K.

yholio 6y ago
Well, you cannot pack trains of 2K people at 90 seconds, because you reach a limit with people getting in and off in the stations, the whole system slows down with trains waiting their turn to enter the station, so real throughput decreases drastically. Additionally, infrastructure costs are much higher for similar peak rates since subway tunnels remove 3x more dirt volume, and require proportional structural materials (7.3 m bore holes vs the current Borring prototypes of 4.2m) Also, there is a more fundamental problem with reaching high thoughtputs with mass transit: you need to force people out of optimal routes from their distributed destinations and origins, into enforced stations. This makes sense for point to point links like LA to SF, but it's very inefficient when trying to cover a 2D city: the more routes and stations you add, the less you are likely to reach peak capacity of any one link. If you are going for city-wide subway, you will pay much, much more to build large, expensive tunnels that will stay mostly idle at the perifery of the system.
- lmm 6y ago
  > you reach a limit with people getting in and off in the stations, the whole system slows down with trains waiting their turn to enter the station, so real throughput decreases drastically. Yes, and this would be an even bigger problem for your proposal, that's the point. > Also, there is a more fundamental problem with reaching high thoughtputs with mass transit: you need to force people out of optimal routes from their distributed destinations and origins, into enforced stations. This makes sense for point to point links like LA to SF, but it's very inefficient when trying to cover a 2D city: the more routes and stations you add, the less you are likely to reach peak capacity of any one link. If you are going for city-wide subway, you will pay much, much more to build large, expensive tunnels that will stay mostly idle at the perifery of the system. You're hugely exaggerating the problem. You get some inefficiency yes - if we imagine a grid system then many journeys require a change of line and the average journey is 1.27x longer than an ideal path between two points, assuming people don't change their actions at all (e.g. living on the same line where they work). But that's outweighed by the efficiency gains of mass transit - in a city with a decent subway system that longer journey with a change will still be significantly faster than driving. As for tunnels sitting idle at the periphery of the system, in the real world that's really not the issue you make it out to be, for a number of reasons; housing concentrates along commuting corridors, the places where the population thins out are, by the same token, the places where land is cheap and the train line can run on the surface, and if necessary then trains can turn short or split/join. If you look at the usage levels that subways actually achieve, they're incredibly cheap for what they do.
  - yholio 6y ago
    >> trains waiting their turn to enter the station > Yes, and this would be an even bigger problem for your proposal, that's the point. No. Trains must make every station. A low occupancy pod will only diverge from the high speed lane when it has reached a destination or pickup point. > in a city with a decent subway system that longer journey with a change will still be significantly faster than driving. I don't think anyone disputes that. But this happens because there is no comparable point to point transit system and the existing road network is inefficient. The point of building tunnels is remove those conflict areas and provide direct point to point routes with very high throughput. If, for the same price you can have similar throughput using individual vehicles, then it makes absolutely no sense cram people into comunal transport, force them into unnecessary stops, changes, and waiting times, making them compete for real-estate prices in transit corridors etc.

qayxc 6y ago

> If they run at 2 second intervals, one after the other, [...], a single tunnel can provide a peak throughput of 90 people per minute or 5400 per hour. I like optimism in general, but think about that for just a second. At the vehicles' top speed of ~45km/h, 2 seconds translate to an average distance of just 25m. This leaves very little room for error and isn't enough of a safety margin. Then there's the obvious thing which renders this idea completely impractical: have you ever tried to stop a car going at 45km/h, get out of it and have another person enter the vehicle in well under 2 seconds? That's practically impossible. Also, it's time to rethink cities instead of regurgitating failed concepts (e.g. individual transport within densely populated areas) over and over again. A liveable city should be made for people, not cars (no matter the size). Going through the insane effort of stuffing individual traffic underground wouldn't change anything - you'd just have your congestion during peak hours underground; it wouldn't go away, though.

yholio 6y ago
The recommended spacing for human drivers is 3s, and if you ever drive on a highway, you will see 2s is the norm most drivers actually use at much higher speeds. There is absolutely no issue to reach that spacing for computer divers at 45 Km/h, even if the front vehicle comes to an instantaneous stop, 10 meters is enough to brake. Clearly the stopping and picking up of passengers is not gonna be done on the main lane. Just like with regular cars, pods exit the speed lane, enter a deceleration lane, then stop into the actual station - a series of parking spaces - where people can embark and disembark at will.
- qayxc 6y ago
  How on earth would you have multiple lanes within a glorified utility tunnel? That's even more unrealistic, because now you not only need a main tunnel and emergency exits, you also need a bunch of parallel tunnels with individual lifts/ramps plus lots of room for merging. This is even more impractical. Just to be clear: impractical doesn't mean impossible - it just means that there's no way this can be as economical, safe, and efficient as existing concepts. An actual station or "a series of parking spaces" as you put it, has no advantages over a traditional subway/people mover station in terms of efficiency, cost and space requirements while offering significantly less throughput. I just don't see how any of this would be an improvement in any way.

rjkennedy98 6y ago

> You can fit two such pods side by side in one of the tunnels of the Boring Company Counting cars instead of people again. You should work for the department of transportation.

yholio 6y ago
Some pods will indeed travel empty in the system to rebalance the supply of vehicles into areas of rush hour exodus. But this is a highly predictable event; the pods will be supplied in advance and on less congested, roundabout routes. So it should have little bearing on peak capacity of any single link. At peak, the 1.5 occupancy rate I factored is achievable and quite typical for car commuting.