3 ms·

> 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

by 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.
  - yholio 6y ago
    The improvement lays in the flexibility of the system. In the financial district, you have a large station with similar costs and restraints as existing systems, and with multiple paralel lanes to handle the trafic, merging etc. When you fan out throughout the city, you can build, for the same price of a single subway tunnel, multiple links, and you can build much more micostations, close to where people need to go, with very short ramps and deceleration and acceleration handled cooperatively with the other vehicles, since throughput is no longer critical. And finally, on the last mile, the vehicles goes outside and drives to your suburban home on the existing road network, in areas of low density where no people mover will ever make economic sense. It is this flexibility that makes self driving vehicles a very practical proposition for future cities.

by qayxc 6y ago

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.
- yholio 6y ago
  The improvement lays in the flexibility of the system. In the financial district, you have a large station with similar costs and restraints as existing systems, and with multiple paralel lanes to handle the trafic, merging etc. When you fan out throughout the city, you can build, for the same price of a single subway tunnel, multiple links, and you can build much more micostations, close to where people need to go, with very short ramps and deceleration and acceleration handled cooperatively with the other vehicles, since throughput is no longer critical. And finally, on the last mile, the vehicles goes outside and drives to your suburban home on the existing road network, in areas of low density where no people mover will ever make economic sense. It is this flexibility that makes self driving vehicles a very practical proposition for future cities.