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Of course you're right; my comment was mostly tongue-in-cheek. Actual train operator salaries probably cost BART about $50m annually, not $500m. In both the cas

by zamfi 8y ago

Of course you're right; my comment was mostly tongue-in-cheek. Actual train operator salaries probably cost BART about $50m annually, not $500m. In both the cases of BART and private cars, the money to pay for tracks or roads comes from taxpayers. The trains themselves are now 40+ years old, and are finally being replaced at a cost of ~$300m this year. Grandparent post specifically talked about operating costs though. All that said, trains are basically the most efficient mode of transport from a (number of drivers) / (number of passengers) perspective. But speaking seriously for a moment: - Lyft charges riders about $2/mile in the Bay Area [0] before fees. - The IRS lets you depreciate your vehicle at a rate of $0.545/mile. - A reasonably efficient car burns ~40 mpg on freeway, at $3.50/gallon that's ~$0.09/mile. So, of the $2/mile the riders pay, about 1/3 of that is costs associated with purchasing and operating the vehicle (according to IRS estimates) and fuel. If we eliminate the rest via autonomous driving, and taxis became 65% cheaper, I suspect many people would make much more use of them. [0]: https://www.lyft.com/pricing/SFO https://www.lyft.com/pricing/SFO

perl4ever 8y ago
Utilization rates are 50-58% for Uber or Lyft. When you take it into account that a taxi is not en route 100% of the time, and add the cost (interest, depreciation) of a much more expensive vehicle, I think your 65% savings go up in smoke.
- zamfi 8y ago
  Sorry, I'm not smart enough for this comment to stick with me. Could you walk me through how 50% utilization means the savings go up in smoke? The most compelling thing I can pull from your comment is "autonomous cars will be 3x as expensive as regular cars (at least), so you won't save anything". That may be short-term true, but is almost certainly long-term false. A 50% utilization compared with 100% utilization makes almost no difference in vehicle cost structure -- if anything, it actually increases the labor fraction of taxi cost. If you're driving your car 50% of the time, then wear and milage is the dominant depreciation factor (rather than age). But a human sitting around doing nothing but waiting for that 50% of the time doubles the labor (time) cost of the service, suggesting an even greater savings from eliminating the human driver. What am I missing?
  - perl4ever 8y ago
    I was assuming humans and self-driving cars both get revenue from riders, but don't get paid in between. And I'm interpreting utilization as the percentage of the time that riders are paying.
    - zamfi 8y ago
      The human's time has a cost, and even if the rider doesn't explicitly pay it, it is factored in to the labor cost of the driver. The machine's time cost is time-based depreciation, which is pretty low.

by zamfi 8y ago

perl4ever 8y ago

Utilization rates are 50-58% for Uber or Lyft. When you take it into account that a taxi is not en route 100% of the time, and add the cost (interest, depreciation) of a much more expensive vehicle, I think your 65% savings go up in smoke.

zamfi 8y ago
Sorry, I'm not smart enough for this comment to stick with me. Could you walk me through how 50% utilization means the savings go up in smoke? The most compelling thing I can pull from your comment is "autonomous cars will be 3x as expensive as regular cars (at least), so you won't save anything". That may be short-term true, but is almost certainly long-term false. A 50% utilization compared with 100% utilization makes almost no difference in vehicle cost structure -- if anything, it actually increases the labor fraction of taxi cost. If you're driving your car 50% of the time, then wear and milage is the dominant depreciation factor (rather than age). But a human sitting around doing nothing but waiting for that 50% of the time doubles the labor (time) cost of the service, suggesting an even greater savings from eliminating the human driver. What am I missing?
- perl4ever 8y ago
  I was assuming humans and self-driving cars both get revenue from riders, but don't get paid in between. And I'm interpreting utilization as the percentage of the time that riders are paying.
  - zamfi 8y ago
    The human's time has a cost, and even if the rider doesn't explicitly pay it, it is factored in to the labor cost of the driver. The machine's time cost is time-based depreciation, which is pretty low.