4 ms·

What? Sure there is. There's an enormous amount of space under every city to dig through before it becomes impractical to reach.

• bobthepanda 7y ago
  The problem is access/exit points to the surface. Graded ramps are high capacity but take up a lot of space since the grade can't be all that steep. Elevators don't take up a lot of space but are really slow, and have worse reliability issues due to the moving parts. How many spots on the surface exist that you could just take a chunk out of for either? Most land in existing cities is already being used for buildings or roads or sidewalks.
  • njarboe 7y ago
    You can have stations underground where the automatic cars/busses stop and drop off people and then the people exit to the surface.
    • bluGill 7y ago
      IE a subway. Which works well for trains. No need to call them cars or buses, since they never leave the guide way and there are advantages to trains in fix route situations
      • njarboe 7y ago
        They can leave far out in the suburbs and other areas of low density and then switch in areas of high density. This would be something new. Hard to realize but a hybrid of the current system that can be the best of both.
    • bobthepanda 7y ago
      That's what subway stations are today. They are absolutely massive to move people quickly in and out, and are the main component of subway building costs. This metro station being built in Paris is 300,000 cubic meters: http://www.leparisien.fr/val-de-marne-94/villejuif-la-gare-circulaire-apparait-aux-pieds-de-gustave-roussy-20-08-2018-7858272.php http://www.leparisien.fr/val-de-marne-94/villejuif-la-gare-c...