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>How do you tell it where to go? the giant ipad on the dashboard of your tesla, or your phone otherwise. >If you merge lanes, wouldn't there be jams there? If

by elif 9y ago

>How do you tell it where to go? the giant ipad on the dashboard of your tesla, or your phone otherwise. >If you merge lanes, wouldn't there be jams there? If instead you build many parallel tunnels [etc] because if the increased speed, one lane is the equivalent of about 2.5 highway lanes in terms of throughput per hour. Regarding safety distance, I think you can actually safely achieve smaller spacing with a roller-coaster style mechanism than with tires on asphalt. I would say that as well is a 2x throughput multiplier. So parallelization seems largely unnecessary. >How is it meant to compete on price or human bandwidth with subways? ok so take an 8 car subway train with 40 people per car on a 10 minute interval. 8 * 40 * 6 = 1920 people per hour travel from A to B. then take sleds each containing a car with 2 people, paced 300ft apart traveling at 125mph. that is 2 people * (125mph / 0.0568182mi) = 4400 people per hour

espadrine 9y ago
> take sleds each containing a car with 2 people, paced 300ft apart traveling at 125mph. that is 2 people (125mph / 0.0568182mi) = 4400 people per hour* I think 300 ft is for 75 mph. Using https://en.wikipedia.org/wiki/Braking_distance https://en.wikipedia.org/wiki/Braking_distance, the distance at 125 mph is 55 m/s * 55 m/s / (2 * 1 * 10 m/s2) = 150 m = 500 ft, resulting in 2 people * 125 mph / 0.09 mi = 2.8 khumans/h. (On the demo video, their vehicles look like they are tire-on-asphalt.) Also, subways have a typical capacity closer to 30 khumans/h in dense urban areas (https://www.thoughtco.com/passenger-capacity-of-transit-2798765 https://www.thoughtco.com/passenger-capacity-of-transit-2798...).
- Robotbeat 9y ago
  The vehicles use a monorail, not asphalt. Both in the concept video and the actual prototype of the electric sled in a tube video. Also, the concept video shows multi-user pods. If you pack them as full as a rush hour subway, you could probably equal or exceed a subway's throughput.
ACow_Adonis 9y ago
Using actual numbers: Melbourne's light rail E-class trams have a carrying capacity of 64 seated: 146 standing. They can regularly mix with pedestrians. The E class is the "big" one at about 40 seconds: https://www.youtube.com/watch?v=kmBlZ4xpS5Q https://www.youtube.com/watch?v=kmBlZ4xpS5Q Melbournes older, 6 car trains have a crush capacity of ~1526. Seatwise they have ~500-600, with a standard target capacity of about 800 (above that the extra variance/numbers people start to complain about overcrowding). Seen here: https://www.youtube.com/watch?v=4AfbBVXGJzY https://www.youtube.com/watch?v=4AfbBVXGJzY Now, those old trains aren't the newest, and they're single-decker and not the biggest or double-decker like sydney's, and they're not the bestest like some of the asian fully-auto metros. But, my point being is that by the numbers before we start getting too crowded, our quite average older 6 car trains have point in time comfortable capacity about 2-3 times more than your 8 car subway estimate. Hell, three of our light rail vehicles regularly move the numbers of your 8-car subway. But wait... We've not actually accounted for the trips accurately, because if a train runs the full length of its track only carrying its estimated point in time comfortable capacity, the carriages would be quite empty: the total passengers using a train aren't its point-in-time-carrying capacity, but how many get on and off between all the stops along its path. That goes for light rail too. So to find the actual number of people moved by train or light rail, you generally have to multiply the carrying capacity by some additional multiple. On the other hand, private vehicles generally, in practice have a person per vehicle estimate UNDER 2 (barring geography, time, purpose variances), meaning your estimate is overly optimistic for the cars, and out by about an order of magnitude for the rail vehicles. I was not being facetious when I made another comment in this thread when I said I was shocked by how inefficient private vehicles were when I actual went down to the intersection and started counting how long it took them to move say 100 people (equivalent of 1 of our trams), nor am I being facetious when I say not only that this is likely a problem with an already known solution, but a problem where The Boring Companies apparent solution is starting with a rough order-of-magnitude efficiency penalty. I'm honestly a bit...feel like I'm taking crazy pills...that people are talking about the proposal of putting private individual vehicles on rails...in tunnels.
- ericd 9y ago
  I totally agree with you that cars are hilariously inefficient. Let alone single occupancy cars. The problem is that most US cities are completely unwalkable, so you need a car once you hop out of the station, or you need an incredibly large subway system. This is being proposed for LA initially, which is one of the most sprawled, least walkable cities in the US. I wish we had more walkable cities here.
Gravityloss 9y ago
I think your assumptions are not valid. Subways usually go much more often than once per 10 minutes.
- elif 9y ago
  In the US?
  - mabramo 9y ago
    In NYC, yes. During rush hour, the local subways come every 5 minutes at most. I think a safe estimate is about 15 trains every hour. The express subways are spaced out a little more, closer to 8 or 10 minutes, depending on the line.
    - elif 9y ago
      peak of the most active system is not the same thing as "usual" here is LA for instance, about 10 minutes average during rush hour https://media.metro.net/documents/5a366ef8-2013-4d21-8e6d-e7716ec50478.pdf https://media.metro.net/documents/5a366ef8-2013-4d21-8e6d-e7...
      - deleted 9y ago
        [deleted]

by elif 9y ago

espadrine 9y ago

> take sleds each containing a car with 2 people, paced 300ft apart traveling at 125mph. that is 2 people (125mph / 0.0568182mi) = 4400 people per hour* I think 300 ft is for 75 mph. Using https://en.wikipedia.org/wiki/Braking_distance https://en.wikipedia.org/wiki/Braking_distance, the distance at 125 mph is 55 m/s * 55 m/s / (2 * 1 * 10 m/s2) = 150 m = 500 ft, resulting in 2 people * 125 mph / 0.09 mi = 2.8 khumans/h. (On the demo video, their vehicles look like they are tire-on-asphalt.) Also, subways have a typical capacity closer to 30 khumans/h in dense urban areas (https://www.thoughtco.com/passenger-capacity-of-transit-2798765 https://www.thoughtco.com/passenger-capacity-of-transit-2798...).

Robotbeat 9y ago
The vehicles use a monorail, not asphalt. Both in the concept video and the actual prototype of the electric sled in a tube video. Also, the concept video shows multi-user pods. If you pack them as full as a rush hour subway, you could probably equal or exceed a subway's throughput.

ACow_Adonis 9y ago

Using actual numbers: Melbourne's light rail E-class trams have a carrying capacity of 64 seated: 146 standing. They can regularly mix with pedestrians. The E class is the "big" one at about 40 seconds: https://www.youtube.com/watch?v=kmBlZ4xpS5Q https://www.youtube.com/watch?v=kmBlZ4xpS5Q Melbournes older, 6 car trains have a crush capacity of ~1526. Seatwise they have ~500-600, with a standard target capacity of about 800 (above that the extra variance/numbers people start to complain about overcrowding). Seen here: https://www.youtube.com/watch?v=4AfbBVXGJzY https://www.youtube.com/watch?v=4AfbBVXGJzY Now, those old trains aren't the newest, and they're single-decker and not the biggest or double-decker like sydney's, and they're not the bestest like some of the asian fully-auto metros. But, my point being is that by the numbers before we start getting too crowded, our quite average older 6 car trains have point in time comfortable capacity about 2-3 times more than your 8 car subway estimate. Hell, three of our light rail vehicles regularly move the numbers of your 8-car subway. But wait... We've not actually accounted for the trips accurately, because if a train runs the full length of its track only carrying its estimated point in time comfortable capacity, the carriages would be quite empty: the total passengers using a train aren't its point-in-time-carrying capacity, but how many get on and off between all the stops along its path. That goes for light rail too. So to find the actual number of people moved by train or light rail, you generally have to multiply the carrying capacity by some additional multiple. On the other hand, private vehicles generally, in practice have a person per vehicle estimate UNDER 2 (barring geography, time, purpose variances), meaning your estimate is overly optimistic for the cars, and out by about an order of magnitude for the rail vehicles. I was not being facetious when I made another comment in this thread when I said I was shocked by how inefficient private vehicles were when I actual went down to the intersection and started counting how long it took them to move say 100 people (equivalent of 1 of our trams), nor am I being facetious when I say not only that this is likely a problem with an already known solution, but a problem where The Boring Companies apparent solution is starting with a rough order-of-magnitude efficiency penalty. I'm honestly a bit...feel like I'm taking crazy pills...that people are talking about the proposal of putting private individual vehicles on rails...in tunnels.

ericd 9y ago
I totally agree with you that cars are hilariously inefficient. Let alone single occupancy cars. The problem is that most US cities are completely unwalkable, so you need a car once you hop out of the station, or you need an incredibly large subway system. This is being proposed for LA initially, which is one of the most sprawled, least walkable cities in the US. I wish we had more walkable cities here.

Gravityloss 9y ago

I think your assumptions are not valid. Subways usually go much more often than once per 10 minutes.

elif 9y ago
In the US?
- mabramo 9y ago
  In NYC, yes. During rush hour, the local subways come every 5 minutes at most. I think a safe estimate is about 15 trains every hour. The express subways are spaced out a little more, closer to 8 or 10 minutes, depending on the line.
  - elif 9y ago
    peak of the most active system is not the same thing as "usual" here is LA for instance, about 10 minutes average during rush hour https://media.metro.net/documents/5a366ef8-2013-4d21-8e6d-e7716ec50478.pdf https://media.metro.net/documents/5a366ef8-2013-4d21-8e6d-e7...
    - deleted 9y ago
      [deleted]