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> Public transportation could take the form of government-owned fleets of self-driving electric cars It absolutely could not, here simply is not enough space f

> Public transportation could take the form of government-owned fleets of self-driving electric cars It absolutely could not, here simply is not enough space for all those cars. A heavy rail metro line can carry up to 60 thousand passengers per hour per direction, which is the equivalent of a 30 lane highway.

ironmagma 4y ago
Who says the self driving vehicles won’t be articulated buses?
- asdff 4y ago
  Every company currently trying to sell a self driving car
  - ironmagma 4y ago
    Just because that’s the current market strategy doesn’t mean governments won’t hire those companies on contracts to run buses. It would be a lot cheaper than paying human drivers most likely, but even more than that it’s probably easier to build and maintain a bus and dedicated tunnel/lane than it is to build and maintain a railroad track.
    - asdff 4y ago
      People claim its an easy pivot all the time but these sorts of industries just do not seem to overlap, and these companies today seem to have zero interest making a go at this sector. There is no tesla articulated bus or a ford articulated bus. Maybe driverless busses will happen, but will it be waymo or anyone available on the market today? I doubt it. I would think it would be whoever makes an articulated bus today licensing that tech from whoever based on the fact that no one in the car market cares to bother with the articulated bus market today.
      - ironmagma 4y ago
        Whether it’s the specific car companies that exist now is sort of uninteresting to me, I guess. Once AVs are deployed, the whole sector becomes way less risky because there is an example of a successful business model, and more funding can be attracted by various parties to support more AV development, both by startups and governments. Either way, the exact vendor of the vehicle is a matter of trivia to the AV company, since the majority of the hard work goes into the software. Private companies have been servicing government contracts for decades, so I think it would happen if a government wanted it to.
kortilla 4y ago
> A heavy rail metro line can carry up to 60 thousand passengers per hour per direction, which is the equivalent of a 30 lane highway. Where did this stat come from? Caltrain fits about 650 and couldn’t possibly run once per 45 seconds to achieve that.
- thescriptkiddie 4y ago
  I got it from here: https://en.wikipedia.org/wiki/Passengers_per_hour_per_direction#/media/File:Passenger_Capacity_of_different_Transport_Modes.png https://en.wikipedia.org/wiki/Passengers_per_hour_per_direct... Heavy rail metro refers to a system like the NYC subway, whereas Caltrain would be classified as suburban rail. A typical NYC subway train has 10 cars with room for 100 passengers each, so to achieve 60k p/h/d would require 60 second headways. This is shorter than the 90 second headways achieved in practice, though theoretically possible with automatic train control and platform screen doors. For a more realistic example, the cars have a crush loading of around 150 passengers, which means 60k p/h/d is possible with 90 second headways. Suburban rail actually has a higher theoretical capacity than heavy rail metro, but this is achieved with very large trains rather than high frequency. Caltrain's new Stadler KISS EMUs will have a capacity of around 200 passengers and will operate in 7 car trains and 10 minute headways, so they will only achieve 8.4k p/h/d initially. However if we assume 300 passenger crush loading and 10 car trains, it could theoretically achieve 60k p/h/d with more reasonable 180 second headways. Now running trains at crush load routinely doesn't make for a great passenger experience, but keep in mind that we are assuming a dual track railroad here. If you are willing to spare the extra 2 highway lanes' worth of right of way, you can lay quad track and run twice as many trains. Many NYC subway lines were built quad tracked so that express trains could pass locals, and Caltrain's ROW is more than wide enough to accommodate retrofitting another pair of tracks.
- ben-schaaf 4y ago
  Caltrain lists over 1000 people on board in Sunnyvale and that's with only 5-6 cars: https://www.caltrain.com/media/3442/download?inline https://www.caltrain.com/media/3442/download?inline. Add more cars, improve signaling and boarding and a train every ~2 minutes seems entirely reasonable for the route capacity of heavy rail: https://en.wikipedia.org/wiki/Route_capacity https://en.wikipedia.org/wiki/Route_capacity

ironmagma 4y ago

Who says the self driving vehicles won’t be articulated buses?

asdff 4y ago
Every company currently trying to sell a self driving car
- ironmagma 4y ago
  Just because that’s the current market strategy doesn’t mean governments won’t hire those companies on contracts to run buses. It would be a lot cheaper than paying human drivers most likely, but even more than that it’s probably easier to build and maintain a bus and dedicated tunnel/lane than it is to build and maintain a railroad track.
  - asdff 4y ago
    People claim its an easy pivot all the time but these sorts of industries just do not seem to overlap, and these companies today seem to have zero interest making a go at this sector. There is no tesla articulated bus or a ford articulated bus. Maybe driverless busses will happen, but will it be waymo or anyone available on the market today? I doubt it. I would think it would be whoever makes an articulated bus today licensing that tech from whoever based on the fact that no one in the car market cares to bother with the articulated bus market today.
    - ironmagma 4y ago
      Whether it’s the specific car companies that exist now is sort of uninteresting to me, I guess. Once AVs are deployed, the whole sector becomes way less risky because there is an example of a successful business model, and more funding can be attracted by various parties to support more AV development, both by startups and governments. Either way, the exact vendor of the vehicle is a matter of trivia to the AV company, since the majority of the hard work goes into the software. Private companies have been servicing government contracts for decades, so I think it would happen if a government wanted it to.

kortilla 4y ago

> A heavy rail metro line can carry up to 60 thousand passengers per hour per direction, which is the equivalent of a 30 lane highway. Where did this stat come from? Caltrain fits about 650 and couldn’t possibly run once per 45 seconds to achieve that.

thescriptkiddie 4y ago
I got it from here: https://en.wikipedia.org/wiki/Passengers_per_hour_per_direction#/media/File:Passenger_Capacity_of_different_Transport_Modes.png https://en.wikipedia.org/wiki/Passengers_per_hour_per_direct... Heavy rail metro refers to a system like the NYC subway, whereas Caltrain would be classified as suburban rail. A typical NYC subway train has 10 cars with room for 100 passengers each, so to achieve 60k p/h/d would require 60 second headways. This is shorter than the 90 second headways achieved in practice, though theoretically possible with automatic train control and platform screen doors. For a more realistic example, the cars have a crush loading of around 150 passengers, which means 60k p/h/d is possible with 90 second headways. Suburban rail actually has a higher theoretical capacity than heavy rail metro, but this is achieved with very large trains rather than high frequency. Caltrain's new Stadler KISS EMUs will have a capacity of around 200 passengers and will operate in 7 car trains and 10 minute headways, so they will only achieve 8.4k p/h/d initially. However if we assume 300 passenger crush loading and 10 car trains, it could theoretically achieve 60k p/h/d with more reasonable 180 second headways. Now running trains at crush load routinely doesn't make for a great passenger experience, but keep in mind that we are assuming a dual track railroad here. If you are willing to spare the extra 2 highway lanes' worth of right of way, you can lay quad track and run twice as many trains. Many NYC subway lines were built quad tracked so that express trains could pass locals, and Caltrain's ROW is more than wide enough to accommodate retrofitting another pair of tracks.
ben-schaaf 4y ago
Caltrain lists over 1000 people on board in Sunnyvale and that's with only 5-6 cars: https://www.caltrain.com/media/3442/download?inline https://www.caltrain.com/media/3442/download?inline. Add more cars, improve signaling and boarding and a train every ~2 minutes seems entirely reasonable for the route capacity of heavy rail: https://en.wikipedia.org/wiki/Route_capacity https://en.wikipedia.org/wiki/Route_capacity