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Digging a single tunnel under the length of London (the Crossrail project) cost ~$25 billion. And that's just one tunnel. London has a population of ~8.5 millio

Digging a single tunnel under the length of London (the Crossrail project) cost ~$25 billion. And that's just one tunnel. London has a population of ~8.5 million, and a single road lane with automated vehicles can handle around ~3,000 cars per hour. Multiply it out, and the cost of tunnelling a road system large enough to carry the entire city at high speed becomes mind-bogglingly huge.

stretchwithme 11y ago
I said "WHEN our driverless cars head underground". I did not say all the travel would be underground. Small single passenger vehicles can also pass each a lot more easily in the amount of space a train takes up. You could have two levels in the amount of vertical space a train takes up. I also don't think a train takes up less of the available space and time than individual cars would, when has to stop at all the stops. All other trains must wait too. The flow is constantly interrupted. Robotic underground construction is also going to be a lot cheaper. Whatever happens and whatever the mix between walking and vehicle transportation evolves, people are going to prefer to travel in their own vehicles over being crammed into cars with strangers and having to navigate escalators. This particular system is shaped by the current technological constraints, not so much by people's desires. When technology advances, it will eventually change.
- fredoralive 11y ago
  I don't think you've seen a London Underground deep tube line, you ain't getting two levels of cars in that space. No overtaking either, as they use separate tubes for each direction. Even the larger, shallower subsurface lines are UK loading gauge, which isn't big enough for double decker trains. I doubt any double decked traffic on existing UK railway land without extensive expensive rebuilding. As for "robotic underground construction", it's not like they have a load of Navvies digging by hand nowadays, a modern tunnel boring machine is pretty damn robotic, but it still costs a fair chunk of change to tunnel.

stretchwithme 11y ago

I said "WHEN our driverless cars head underground". I did not say all the travel would be underground. Small single passenger vehicles can also pass each a lot more easily in the amount of space a train takes up. You could have two levels in the amount of vertical space a train takes up. I also don't think a train takes up less of the available space and time than individual cars would, when has to stop at all the stops. All other trains must wait too. The flow is constantly interrupted. Robotic underground construction is also going to be a lot cheaper. Whatever happens and whatever the mix between walking and vehicle transportation evolves, people are going to prefer to travel in their own vehicles over being crammed into cars with strangers and having to navigate escalators. This particular system is shaped by the current technological constraints, not so much by people's desires. When technology advances, it will eventually change.

fredoralive 11y ago
I don't think you've seen a London Underground deep tube line, you ain't getting two levels of cars in that space. No overtaking either, as they use separate tubes for each direction. Even the larger, shallower subsurface lines are UK loading gauge, which isn't big enough for double decker trains. I doubt any double decked traffic on existing UK railway land without extensive expensive rebuilding. As for "robotic underground construction", it's not like they have a load of Navvies digging by hand nowadays, a modern tunnel boring machine is pretty damn robotic, but it still costs a fair chunk of change to tunnel.