Boring company

[Green Baron]

Just think of the safety regulations and constructive elements tunnels need these days to be open to public traffic. This demo tunnel is in the range of the emergency rooms and side tunnels for rescue, material transport and maintenance of modern road- or train tunnels, and these are dug for km through hard rock.

240km/h for individual cars ? In case of an accident there will be a compacted plug of plastic, aluminium, battery packs and a few organic compounds in a matter of seconds. Or they'll have to increase separation between cars in a way that only a few can get through per unit of time.

Really, i expected more.

Edited December 19, 2018 by Green Baron

[YNM]

Pedestrians and Cyclist on Gasoline/Electric Cars ?

I can't see my pee boiling more than hearing this s*** crap. This is just an excuse to continue making dem freedom freeways underground isn't it.

Cars are space inefficient, period.

Edited December 19, 2018 by YNM

[tater]

55 minutes ago, YNM said:

Pedestrians and Cyclist on Gasoline/Electric Cars ?

I can't see my pee boiling more than hearing this s*** crap. This is just an excuse to continue making dem freedom freeways underground isn't it.

Cars are space inefficient, period.

Cars are what we have. What our cities are designed for. We cannot retroactively change that, and "mass transit" simply does not work given how spread out they are (you still need a car once you reach your destination on transit). Get back to us after you've spent some time in a western US city that is not SFO.

Edited December 19, 2018 by tater

[YNM]

5 minutes ago, tater said:

Cars are what we have.

Alright, yeah, I've battled with that to death in this very thread, and I'm just going to casually remind you my absolute remark for it.

 

But even so, because road vehicles are running inside it, so it's definitely a public right-of-way, where's the consent of every landowners above it whose rights has been taken ? Did they wholy agreed to it ? Were there comments ? Suggestions ? Protests ?

I hope some gas mains company start lining that tunnel with gas mains, which is absolutely legal to be put along public right-of-ways.

[tater]

It’s not a public road. Landowners don’t own deeper than they are likely to dig. Many houses (most?) in the west don’t even have basements. Regardless, they have lawyers who know more than we do about it.

The YouTube vid is not an answer (can’t watch it anyway). US cities are not changing on the sort of timescale we are talking about (say Musk’s lifetime, or his kids). LA is really spread out, and no mass transit can make it walkable. If you can’t easily walk once you get within a km of a target area, mass transit is a non-starter.

[YNM]

8 minutes ago, tater said:

Landowners don’t own deeper than they are likely to dig. 

I think I read somewhere that the tunnels are really shallow... maybe the top bit is within the "reasonable depth" sections.

If it's not a public road, shouldn't they own the land ? Or at least have a statute (like railways do). But railways need to follow FRA regulations... which "self-driving trains with GPS and surrounding sensors" aren't in the standards (and so requires extensive off-the-public testing). Not to mention if it was railways you probably have a much harder time having the environmental waiver. Mining shafts ? Hahaha.

This is why it's just all crap. If they had wanted an actual test tunnel do it in the depth of mojave desert, no one will care.

Edited December 19, 2018 by YNM

[tater]

No one cares in LA, either. Why are you so concerned with what someone is doing with his own money in LA? Tunneling has been a thing for a long, long time, and no one has decided to do it with their own money so far. It’s like old space, they would if the government paid them many billions to do it. It’s no skin off my teeth how Elon spends his cash.

[magnemoe]

3 hours ago, Green Baron said:

Just think of the safety regulations and constructive elements tunnels need these days to be open to public traffic. This demo tunnel is in the range of the emergency rooms and side tunnels for rescue, material transport and maintenance of modern road- or train tunnels, and these are dug for km through hard rock.

240km/h for individual cars ? In case of an accident there will be a compacted plug of plastic, aluminium, battery packs and a few organic compounds in a matter of seconds. Or they'll have to increase separation between cars in a way that only a few can get through per unit of time.

Really, i expected more.

This could be classified as an rail tunnel rater than an road one who is easier. 240 km/h is very fast even for rail only relevant for longer stretches. You take time accelerating and you can not turn fast. You also need serious safety margins.
Now trying to merge lanes and similar that that speed would be interesting. 

Not sure about this might work but probably more for as an extra layer of highways. One issue is capacity, capacity is far lower than roads and it will be issues getting onto the system. The idea with the street level elevator is idiotic, I would rated have terminals you drive down an ramp and wait for you trolley slot, at end location you drive off and the trolley moves to the inn queue or return. 

[YNM]

2 minutes ago, magnemoe said:

This could be classified as an rail tunnel

So it needs FRA approval then ?

[tater]

1 hour ago, magnemoe said:

This could be classified as an rail tunnel rater than an road one who is easier. 240 km/h is very fast even for rail only relevant for longer stretches. You take time accelerating and you can not turn fast. You also need serious safety margins.
Now trying to merge lanes and similar that that speed would be interesting. 

Not sure about this might work but probably more for as an extra layer of highways. One issue is capacity, capacity is far lower than roads and it will be issues getting onto the system. The idea with the street level elevator is idiotic, I would rated have terminals you drive down an ramp and wait for you trolley slot, at end location you drive off and the trolley moves to the inn queue or return. 

The animations never show merging very well. You'd need multiple tubes for a given "highway" section I'd think. Side tunnels have to be somewhat non-trivial, since the righ has some substantial length to it, and a preferred direction. So a main tunnel, then an off/on ramp section that bears off, then on for each stop (assuming all such cars can accelerate at at least 0-transit speed within the on ramp section, several hundred meters I would imagine (they need to get to 240 kph). That's also the limit on how close stops can be (then can be closer, but farther off-axis).

As shown, there is no trolley slot (sled/skate/whatever). Enabled cars would have to have retractable guide wheels along the sides. The issue with this of course is that because Boring would not be in control of the skates, any failure (even out of charge for random car) stops all traffic.

This is my big issue... I don't care about Musk doing this at all, but it seems pretty kooky to me.  It seems like the tunnels need to have pedestrian access to the surface every few hundred meters at most in case of emergencies (random electric car runs out of charge in the middle of the road, there is no way to tow it, no way to get cars behind it out save exiting backwards to last exit (with all cars behind that bailing at next elevator). Seems like any such system needs some robust alternative ways to move traffic.

For example, every tube requires multiple, parallel tubes, and they need to have merge capability every few hundred meters such that one being blocked merely sorts cars to other lanes. Some side exits should not be available for users, but should perhaps contain tow vehicles that can push any stopped cars out to an exit. He shows multiple tunnels for scalability, but not the fact (seems a fact to me) that multiple tunnels are absolutely required for even minimal functionality.

[StrandedonEarth]

It would probably work better as a toll highway similar to the 407 (IIRC) tollway around Toronto, where one could pay a toll to take the tunnels under the gridlock, saving loads of time. This way the tunnels shouldn’t get overloaded if the tolls are priced right, but it would still reduce traffic on the surface streets and freeways.

The elevators would probably work pretty well for pedestrians, as the vehicle could load up with people on the surface then drop down and crank the hyperdrive.  

[tater]

2 hours ago, StrandedonEarth said:

The elevators would probably work pretty well for pedestrians, as the vehicle could load up with people on the surface then drop down and crank the hyperdrive.  

I was thinking in the event of an emergency. Tunnel fires are a thing, which is why there are requirements for exits every certain number of meters.

[Nightside]

1 hour ago, tater said:

I was thinking in the event of an emergency. Tunnel fires are a thing, which is why there are requirements for exits every certain number of meters.

That's why we need to upgrade to the vacuum version.

[Mad Rocket Scientist]

They must be confident in their braking, this is even more than 1 vehicle/sec.

Does anyone have any resources on how braking and friction works in cars? Is deceleration constant with computer controlled braking? I'd like to run some numbers on this. The first question is what kind of accidents are possible in a tunnel with self-driving cars, and how fast they would decelerate the vehicle. Anyone have any ideas?

If the above figure is within an order of magnitude of the final cost this would be an amazing boon to any underground project. 

This makes it sound like there may be some convergence with subways for loop, which brings up an interesting question in trying to judge whether this would be better or worse than subways: How should success of a transit system be measured? People using it? People's happiness with it? Cost to the user or the operator? Environmental impact?

[Green Baron]

Similar things have been extensively examined in the 60s and 70s, for example dedicated lanes and cars in a row at high speeds, automatically keeping distances via radar (systems that exist today but are still not totally reliable). But it was decided then that pulling in and out and other situations that are difficult to calculate like a defect in one car would be too dangerous and could trigger chain reactions (sedimentary processes like cross lamination and diagonal bedding, or simple diagenesis (compacting) ;-)). Then came the oil crisis and it wasn't that important any more. Today, construction of roads with money borrowed from the future apparently seems more apt ...

But, really, cars with 250km/h < 1sec spacing ? I firmly believe that is just pr ventilation, at least from a safety point of view. I can imagine they leave the compacted mess where it is, plant a cross on top, and dig a new tunnel at the side after an "anomaly" ....

Edited December 20, 2018 by Green Baron

[YNM]

1 hour ago, Green Baron said:

cars with 250km/h < 1sec spacing ?

Not even CBTC or ETCS L3 can do that.

7 hours ago, StrandedonEarth said:

as a toll highway

So it's a public right-of-way, and gas companies can absolutely legally put gas mains alongside it ?

3 hours ago, Nightside said:

That's why we need to upgrade to the vacuum version.

Added with gas leaks... yes. Good.

 

As I've said before, Musk avoiding all legals is just setting his own foot for the deepest legal quagmire ever imaginable (or even beyond it).

[cubinator]

4 hours ago, Nightside said:

That's why we need to upgrade to the vacuum version.

Can't have a fire in the tunnel if there's no oxygen to begin with!

Would that mean space-proof Teslas? hmmm...

Edited December 20, 2018 by cubinator

[mikegarrison]

19 hours ago, Mad Rocket Scientist said:

Does anyone have any resources on how braking and friction works in cars? Is deceleration constant with computer controlled braking? I'd like to run some numbers on this.

There is plenty of information available on this subject. The bible on this is probably Milliken. https://www.amazon.com/Vehicle-Dynamics-William-Milliken-Hardcover/dp/B00GSCTN2U

The think to know is that brakes are always designed to work better than tires, so the actual limit to braking force is the tire (unless you overload the heat capacity of the brakes).

Edited December 20, 2018 by mikegarrison

[YNM]

5 hours ago, mikegarrison said:

the actual limit to braking force is the tire (unless you overload the heat capacity of the brakes).

Additionally, the occupants want a certain level of comfort, otherwise there's no difference between "braking" and "crashing".

[mikegarrison]

9 minutes ago, YNM said:

Additionally, the occupants want a certain level of comfort, otherwise there's no difference between "braking" and "crashing".

Not really a consideration. The limit of tire adhesion in a car without significant downforce is usually about 1g of deceleration. Crashes are, of course, much higher.

In an emergency you simply want to apply the brakes to the full extent that the tires can supply grip. ABS systems are already designed to do this. (In fact, many cars now feature an emergency braking assist, because most drivers are reluctant to use their brakes to 100% capacity. Full 100% ABS braking is a rather violent experience, but still much better than a crash.)

Edited December 21, 2018 by mikegarrison

[YNM]

8 minutes ago, mikegarrison said:

In an emergency you simply want to apply the brakes to the full extent that the tires can supply grip.

I was talking of normal use here.

Usually, trains and busses are limited to around 2,5 m/s² in normal service (about 0.25 g). Not sure what the plan is to achieve 250 kph (69.5 m/s) and decelerate back in a snug-fitting 2500 m long tunnel, with bends and whatnot...

[mikegarrison]

1 minute ago, YNM said:

I was talking of normal use here.

Usually, trains and busses are limited to around 2,5 m/s² in normal service (about 0.25 g). Not sure what the plan is to achieve 250 kph (69.5 m/s) and decelerate back in a snug-fitting 2500 m long tunnel, with bends and whatnot...

I see. I think the post I was responding to was talking about maximum braking effort.

The reason people are reluctant to use maximum braking in an emergency is that it is so very much more violent than normal braking. I have ridden in cars as a performance driving instructor, and it can be difficult to convince novices to just mash down on the brake as hard as they can. As they get thrown into the belts and the ABS starts pounding like a rivet gun, they naturally want to back off the pedal.

Of course, in a car without ABS things are different, and it's much harder to approach maximum braking because it takes a tremendous amount of skill to stay right on the edge of locking up the wheels.

[YNM]

14 minutes ago, mikegarrison said:

I think the post I was responding to was talking about maximum braking effort.

Given how snug the tunnel is they probably will get more braking force than needed from air brakes (though only on the start of braking, once it slows down considerably you need the usual brakes).

Also I suppose in trains and busses it is too likely for someone not to be seated during acceleration and braking. (which is partly why it's very efficient as it crams more people in.)

[Green Baron]

6 hours ago, mikegarrison said:

The reason people are reluctant to use maximum braking in an emergency is that it is so very much more violent than normal braking. I have ridden in cars as a performance driving instructor, and it can be difficult to convince novices to just mash down on the brake as hard as they can.

Hehe :-) I recall participating in such a training way back. That was something we had to understand, switching in the brain from "stutter brake" to "just nail the pedal down".

But in this case it doesn't matter. No human and only a bf computer can react at the proposed speeds and distances.

Edited December 21, 2018 by Green Baron

[tater]

Added to this is the fact that Teslas can pretty much drive with just one pedal, right? My buddy got his a few days ago, but he has yet to drive over and take me for a ride. As I understand it, letting off the accelerator pedal can slow you down to a stop by itself (quickly) depending on the settings you choose, making the brake pedal redundant. I wonder if any such speed changes in the tunnel will be made with regenerative braking in mind...