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The Boring Company FAQ

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Re: The Boring Company FAQ

#211

Post by ktta »

njarboe wrote: post #170
ktta wrote: post #116

Earlier quoted context omitted.

See I don't know what specifics they're talking about when they say 'a large network'. It'll obviously be more efficient to dig a wider tunnel than multiple tunnel on a single route. So, unless I'm wrong, to me it looks like it'll only be one tunnel, with one track to and one track back. How many people do you think can be transported in a direction in a 'sled' in one lane? I'm talking about one point to another poin…

The car in the video looks like Model S size. About 16 feet long. Add 2 feet on each end for an even 20 feet for the sled. At 125mph one gets 660,000 feet per hour. So if you can pack the cars next to each other, the maximum is 33,000 cars per hour. So 33,000 people per hour with each person getting a space that would rent in SF for $1000/month. Pack that sled space with people at the same density as a train at rush…

It is very easy to come up with theoretical numbers and look nice. We already know know the subway infrastructure works. Forget what exists currently, and try to calculate the theoretical throughput of the subway system. I bet you'll come up with much more that what it is currently.

On first look at your calculations the flaws I find are these:

1. 125mph is a very, very optimistic number in my opinion. In reality I think anywhere near 100mph is what I would expect.

2. You can't fit 50(!) people in a 20ft x 6.5ft 'sled' for hours. If something goes wrong, they'll trapped in a tunnel with no escape to surface for hours!!!

3. The numbers might make financial sense if you cram them with theoretical people at peak hours. But the thing is, most of the day (and night) those sled will mostly be empty. So you can only count the sleds to be used close to their limit for a couple hours a day morning and night.

4. You can't just daisy chain 33k sleds along the track. As I've said before, one malfunction would possibly wreck havoc in the system. Which can actually lead to people's death. Think of them as you would an airplane, but you can't land in an emergency like you can in an airplane

5. This is close to what @so33 said. The last couple miles and the first couple miles will be very congested because people slow down, and getting off them would take time and many stations. The only way to remove bottlenecks would be to make lots of places to easily disembark, which would increase the costs.

Re: The Boring Company FAQ

#212

Post by hwillis »

discodave wrote: post #48

The old strategy of hiding your outlandish claim in an assertion in the first sentence! "To solve the problem of soul-destroying traffic, roads must go 3D" The word "must" is a very strong one here, there are other options: * Reduce the amount of travel that people need to do (remote work, online shopping). * Reduce the density of cities (enabled by remote work or longer commutes with better internet access). * Incre…

Your solutions are proportional reductions, a % reduction in the number of drivers. The problem of traffic rises with the ~2nd power of population because not only are there more people, there are more intersections.

Intersections can only be solved with 3d roads, by eliminating overlaps. The bigger the city, the more artery roads you need with uninterrupted flow, and they eventually choke each other. Build tunnels and you can have point-to-point connections without choking off local flow.

Reducing the number of drivers can't fully solve gridlock because at some point you have to hit a long light when you try to move from a high flow to low flow area. The only way to avoid that is with onramps and elevated freeways, but you can't build enough of those.

Re: The Boring Company FAQ

#213

Post by hwillis »

discodave wrote: post #48

The old strategy of hiding your outlandish claim in an assertion in the first sentence! "To solve the problem of soul-destroying traffic, roads must go 3D" The word "must" is a very strong one here, there are other options: * Reduce the amount of travel that people need to do (remote work, online shopping). * Reduce the density of cities (enabled by remote work or longer commutes with better internet access). * Incre…

Your solutions are proportional reductions, a % reduction in the number of drivers. The problem of traffic rises with the ~2nd power of population because not only are there more people, there are more intersections.

Intersections can only be solved with 3d roads, by eliminating overlaps. The bigger the city, the more artery roads you need with uninterrupted flow, and they eventually choke each other. Build tunnels and you can have point-to-point connections without choking off local flow.

Reducing the number of drivers can't fully solve gridlock because at some point you have to hit a long light when you try to move from a high flow to low flow area. The only way to avoid that is with onramps and elevated freeways, but you can't build enough of those.

Re: The Boring Company FAQ

#214

Post by elif »

espadrine wrote: post #199
Animats wrote: post #61

So, the key ideas are: - Smaller diameter tunnels. 14' is suggested. This is slightly larger than the deep London Tube lines. - Electrically powered TBMs. Those exist. However, often the business end of the machine is hydraulically powered. Musk is probably thinking of going all electric, at least for the cutter head. After all, he has lots of experience with high-torque electric motors. - Do cutting and tunnel ring…

> Issues glossed over: Soil variability. … The back end. Good points. And beyond the technical aspects, there's a lot that the FAQ doesn't say about the service: - How do you tell your sled where to go? Does it always go to the same place? If so, do you merge lanes? If you merge lanes, wouldn't there be jams there? If instead you build many parallel tunnels, don't you remove the gains you had from building smaller tu…

>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

Re: The Boring Company FAQ

#216

Post by cmarschner »

agjacobson wrote: post #205

This is a little crazy. Because of too much surface traffic, let's bore tunnels and develop sleds. The problem is: inefficient use of the existing infrastructure, 1 person per car, and the like. This wii be improved by the sharing of vehicles, and the driving of vehicles in formations by filing flight paths, using driverless technology. Cars are a highly unattractive investment anyway, a $50,000 car sits unused 23 ho…

Agree with the first point - if the final goal is to move people around at low costs in terms of construction/maintenance, land use, and environmental factors, the low ratio of "transported human" vs. "transported metal" makes cars the worst of all choices. This can also only alleviated for so long by making roads more congested in a more efficient way. In the end, roads are still a massive waste.

Some of your other points make too many assumptions of maintaining a status quo. E.g. automated cars will make sharing schemes more feasible. You can either hop on an uber-like car to get home, or lease your car out in the 96% of the time it sits idle.

Unfortunately (depending on the right price) I think this will make car travel more attractive compared to other forms of transport. One can think of a lot of sharing schemes - individual cars, minibuses, or large busses like we have today - with different price points. Overall costs of motorized travel is likely to fall. So I would think that overall we will see that vehicle use will go up (at the expense of walking on foot, for example) and use of parking lots will go down. In fact if traffic wasn't as cyclic as it is one wouldn't need any parking lots at all.

Also, if you can really get to the 130 or so MPH in the tunnel, then travel time will not be such an issue.

The main fallacy of the whole initiative, however, is that it is based on status quo of the structure of cities. Compare the urban sprawl of a post-WW2 US city with those of a medieval town. The main difference was that travel was slower, and faster travel was incredibly expensive (mostly unreachable due to lacking technology). It led to a much more efficient use of resources. If anything we need to redesign our cities based on these old principles in order to reduce overall resource consumption.

Re: The Boring Company FAQ

#217

Post by cel1ne »

Angostura wrote: post #200
cel1ne wrote: post #187

Earlier quoted context omitted.

Off topic: The more I think about organizations the more I they seem to be the key players preventing change to me. (Which is not necessarily a bad thing) Business says: We had this great idea, now let's freeze everything in time and let's make money of this snapshot forever, because who knows when we'll find gold again. Entertainment industry likes to do that especially.

That's not businesses - that's humans. Or do you apply for a new job every two weeks whenever you see a higher salary advertised?

More precisely it's humans when they form a bunch / organization ;).

Re: The Boring Company FAQ

#218

Post by hwillis »

flashman wrote: post #154
deftnerd wrote: post #41

I'm more interested in the nuances of tunneling, like how they'll handle water seepage and flooding. Flooding is actually a huge problem with climate change causing larger and more frequent major weather events. After Hurricane Sandy, it took almost a week to reopen the subway tunnels. I can just imagine the kind of kinetic force that'll occur if a sled carrying a car slams into a section that has a few feet of water…

> Airflow is necessary to keep passengers safe. This has just made me wonder what happens in emergencies or system failures. Are the tunnels wide enough to open your door or climb out a window? How far apart and numerous are emergency exit hatches? Is there off-grid emergency lighting (e.g. battery-backed)? There would be few things more upsetting than your sled coming to a halt, inside a dark tunnel, and being unabl…

Air isn't really a problem. A person breathes about .5 cubic meters of air per hour, so 100 people trapped for 6 hours will go through 300 cubic meters of air. The diameter of the tunnel being 14', that air supply would take up 68' of tunnel lengthwise. And that's one breath, the air can be breathed many times before the co2 level becomes too high.

The air inside the volume of a coffin can last you a few hours. Unless you are literally shoulder to shoulder with no other air, your oxygen will last as long as you need.

Re: The Boring Company FAQ

#219

Post by adrianN »

astrocat wrote: post #20
atarian wrote: post #3

I'd like to see more details about edge case scenarios. What happens if a sled gets stuck? What would be the procedure and response time for getting the right personnel down there? What failsafes are in place for disasters? What if the power grid went offline or there was a flood? How do you prevent human error? What if people left their gas vehicles on and there was a toxic level of carbon monoxide in the tunnels? W…

> I'd like to see more details about edge case scenarios. The thing is, we're all MUCH more comfortable with the danger we're familiar with, than the danger we're unfamiliar with. Imagine if planes were just being introduced today - what are the edge case scenarios? What happens if there's mechanical failure at 30,000 feet? What happens if there's turbulence, lightning, birds, volcanic ash? What happens if the pilot…

We actually care a lot about all the problems you mentioned with airplanes and there are extremely strict regulations that you need to fulfill before you can put people in your plane.

Re: The Boring Company FAQ

#220

Post by ACow_Adonis »

BurningFrog wrote: post #183
djsumdog wrote: post #151

Earlier quoted context omitted.

But even with the stations, escalators and everything else, you're talking about orders of magnitude between trains and cars. London during peak hour has trains arriving less than 1 min 30 sec apart. They move an absolutely insane amount of people. Singapore's trains are entirely automated and arrive at Everything about Musk's idea seems absolutely terrible. If America had better trains and subways, it could move mas…

One problem is that trains only move an insane amount of people that are all going the same way. Another problem is that all those people have to walk to and from the end station. A "packet switched" system of sending individual cars at high speed solves both those problems, and going just by my gut feel, should have a quite high throughput too.

Here in Melbourne, I used to have a bit of a "gut feel" that it might not be efficient to give over two entire lanes of our roads to our light rail vehicles. Having two lanes sit empty for so long between trams seemed so wasteful. And for what, a single vehicle to come through every minute or two?

Then I sat at an intersection one day and counted how many individuals were being moved through two lanes of regular car traffic vs how many came through on the light rail.

I was shocked by how inefficient regular traffic is.

So now MY gut feel is that without any technological breakthrough, this sort of system would already be starting with an order of magnitude disadvantage: which is to say, shockingly inefficient compared to allready available technology and solutions...

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