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This is already a solved problem. BART may have huge headways, but Vancouver's fully automated Skytrain can run at 75 second headways (!!!).

There is no universe where an SUV holding 4 people is more space efficient than a Skytrain car.




Point to point transport in most cities is not at all a solved problem.

While this was demonstrated with a SUV there’s no reason why this can’t be used for a larger van carrying 6-12 people and tied to a carpool service. 12 people hurtling down this each second is pretty decent capacity, especially multiplied by many tunnels that do an even better job at getting people to the last mile.

It’s a platform, not just a Tesla-mover.


>There is no universe where an SUV holding 4 people is more space efficient than a Skytrain car.

Except universes where a train doesn't pick you up at your house, drive you to the front door at work, take you to your kid's school after work, then take you to drop the kid off at karate practice, then take you directly to the grocery, then back to karate practice, then home but allowing you rapidly move your vehicle through a congested city thereby reducing surface congestion making overall travel conditions more efficient and reducing the need for car parks at public transportation stop for people that live in suburbs.


75 seconds is really, really long. Cars on a highway don't leave 75 seconds in between each other; if a cutting-edge train does, that starts to imply that density issues do exist for subway systems.

And how expensive was it to build the train? If you can build 3x the tunnels for AVs as you can train tunnels and trains for the same price, actual throughput dollar-for-dollar in infra spend would be much better with Boring Co tunnels.

Update with data: it cost $2 billion to build 50 miles of Skytrain. Apparently this prototype Boring Co tunnel cost $10 million per mile. That's a 4x cost advantage for Boring Co mile-for-mile, and I imagine they'll try to strengthen that advantage even further; after all, that's their whole company's purpose: cheap, efficient boring.


>75 seconds is really, really long. Cars on a highway don't leave 75 seconds in between each other

..and? A car also doesn't carry 500 people.


Right, but 15 SUVs 5s apart carry 105 people, and if they can actually travel at an average 150mph, that's faster than the average speed of Skytrain's fastest line by another 3x — so, now we're looking at 315 people moved through the space at the same time.

Factor in cost advantages of the tunnel — 4x cheaper mile-for-mile for the prototype, it seems like? — and the same dollars spent on Boring Co tunnels could actually move a lot more people than Skytrain: you can build 4x the tunnels, moving nearly 1300 people instead of 500.

Even if SUVs can only match the fastest average Skytrain line (50mph), that's still fairly competitive even at the current cost per mile of a Boring Co tunnel. Assuming they can bring cost down further (which is the goal of the company), they could still end up beating trains in terms of people moved per dollar spent.

Listen, I'm not saying it'll happen. But the dismissiveness here reminds me of the "Model 3 will never cost less to build than the price to sell it!!!!!" or "Tesla will never make more than 1000 cars per week!!!" or cash crunch or etc hysteria. I guess Elon attracts that by constantly missing deadlines, but he often still delivers; he just delivers a year or so late.


>15 SUVs, Travelling 150 mph, a second apart

You're fond of throwing in a lot of utterly implausible figures to support your argument here


Despite your pretend block quote, that isn't a direct quote from me (you're taking quotes from someone else in the thread and splicing them into my post, using your made-up version as a strawman). I said 5s apart, which is over 1000ft of spacing — nearly a quarter of a mile, plenty of room for braking — at 150mph; the 15 SUVs is because 75/5 = 15, and we're comparing it to a train system with mandatory minimum 75s gaps.


But 75 cars spaced 1 second apart...


Somehow you assume they will be able to get into that tunnel at these intervals


haha yep.

This plan is like when a city widens a highway but doesn't touch other parts of the road network? What happens? It just moves the choke point somewhere else in the network.


Agreed 1s gaps are too tiny — seems unsafe and that'd be a lot of elevator traffic. 5s seems doable though: assuming 5s gaps, you need an elevator system capable of moving one car every 5s, and then the tunnel is optimally saturated. That doesn't seem insurmountably hard: two elevators that take 10s each to go from surface to tunnel would be enough, along with a bit of on-ramp tunnel to allow cars to accelerate to speed before merging. Throw in a third elevator or a fourth for redundancy while you're at it because elevators are way cheaper than a mile of tunnel, and seems doable.


You're assuming you can get cars into the elevators at 5s intervals.

Almost all assumtions in the discussion start directly in the tunnel, and sometimes at the elevator. Almost no one thinks about: how will cars get into that thing from the road, how the cars will get out of that thing onto the road.


Presumably they'd drive into the elevator on one side, and drive out of the elevator on the other side.


Even if you have a separate elevator for entry and a separate eleveotr for exit: how do you get to a 5s interval?


It's probably just me but I really wouldn't get into anything that was going to be travelling 150mph at 1s intervals. All you need is a tire to go (or something loose on the floor or a dead battery or ...) and you've got not only a huge twisted lump of metal and body parts to untangle, you've almost certainly ruined your tunnel.


You're comparing a prototype with a real life operating system that was built to be um, you know safe and good, unlike what has been shown with this prototype.

The fact is that a 500 capacity train running at 75-100s headways destroys this system capacitywise.

Musk has a long, long way to go before he shows that this idea of his is better than the 1986 era technology at the core of Vancouver's system.


> The fact is that a 500 capacity train running at 75-100s headways destroys this system capacitywise.

This is like that linked tweet: all assertion, no data. What are you using to estimate the theoretical throughput of a Boring Co tunnel system vs Skytrain? Let's debate that. Right now it's all just thin air.

Assumptions I'm willing to believe, and thus make me interested in this prototype's viability:

1. Cars need less space in between them. 5-10s gaps seem more than reasonable based on highway driving. This seems especially true since these are operated autonomously in highly controlled environments, meaning we might need even less distance between cars than free-wheeling, human-operated highway driving.

2. Most train stops are useless for most people — maybe 3x stops per ride on average? Having only one stop per ride would dramatically improve average speed, since a smaller percentage would be spent slowing down, speeding up, or waiting at a station.

3. Smaller tunnels are cheaper to dig, meaning dollar-for-dollar you can build more of them to make up any remaining capacity difference.


You need dozens of those tunnels: the main transport, the side tunnels to speed up incoming and slow down exiting cars etc. etc.

And we also assume that all cars can enter and exit the system with no delays.

It'll be a miracle if it reaches bus capacity, much less train/subway capacity: https://www.thoughtco.com/passenger-capacity-of-transit-2798...


> What are you using to estimate the theoretical throughput of a Boring Co tunnel system vs Skytrain? Let's debate that.

Basic geometry.


That’s not an argument.




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