1175:"Moving Sidewalks"

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Quicksilver
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1175:"Moving Sidewalks"

Postby Quicksilver » Mon Feb 18, 2013 6:09 am UTC

Image
http://xkcd.com/1175/
Alt Text:"I think I could spend hours just stepping on and of conveyor belts moving at various speeds."
I miss the childish days of going up down escalators and vice versa. Those belts would also make the best high five ever.

HagarTopeka1
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Re: 1175:"Moving Sidewalks"

Postby HagarTopeka1 » Mon Feb 18, 2013 6:11 am UTC

This one reminds me of Asimov's The Caves of Steel, where moving walkways are a primary form of high-speed public transportation.

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Re: 1175:"Moving Sidewalks"

Postby rhomboidal » Mon Feb 18, 2013 6:12 am UTC

I'd expect to battle King Koopa once I made it to the middle.

McBee
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Re: 1175:"Moving Sidewalks"

Postby McBee » Mon Feb 18, 2013 6:13 am UTC

At what speed does the high-five location move? :|

madaco
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Re: 1175:"Moving Sidewalks"

Postby madaco » Mon Feb 18, 2013 6:14 am UTC

McBee wrote:At what speed does the high-five location move? :|

six times.
duh.
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Admiralz
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Re: 1175:"Moving Sidewalks"

Postby Admiralz » Mon Feb 18, 2013 6:18 am UTC

It may just be the perspective, but each person seems to be ready to jump onto an arrow facing back at them.
Does anyone think this is intentional or an oversight by the artist?
Because it would seem as if they are taking the intentionally hard (becoming quickly harder) route to that high-five.

Abecedarius
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Re: 1175:"Moving Sidewalks"

Postby Abecedarius » Mon Feb 18, 2013 6:33 am UTC

I think I could spend hours just stepping on and of conveyor belts moving at various speeds...in Portal 2.
That would be awesome.

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Re: 1175:"Moving Sidewalks"

Postby TimXCampbell » Mon Feb 18, 2013 6:39 am UTC

I've heard that a person walks at an average of 2.5 miles per hour. Let's knock that down to 2 because of the concentration it would take to negotiate the speed changes. That means that at the High Five point both people will be travelling at 6x2=12 miles per hour, meaning that even if they keep their hands stationary they'll slap palms at 24 mph.

Hmm. If I was driving my motorcycle at 24 mph, would I want to slap a tree? I don't think I would.

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Quicksilver
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Re: 1175:"Moving Sidewalks"

Postby Quicksilver » Mon Feb 18, 2013 6:43 am UTC

Admiralz wrote:It may just be the perspective, but each person seems to be ready to jump onto an arrow facing back at them.
Does anyone think this is intentional or an oversight by the artist?
Because it would seem as if they are taking the intentionally hard (becoming quickly harder) route to that high-five.
But it makes the high five that much more satisfying.

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Re: 1175:"Moving Sidewalks"

Postby bitwiseshiftleft » Mon Feb 18, 2013 6:56 am UTC

... and this is why I like Robo Rally.

Sandor
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Re: 1175:"Moving Sidewalks"

Postby Sandor » Mon Feb 18, 2013 7:01 am UTC

HagarTopeka1 wrote:This one reminds me of Asimov's The Caves of Steel, where moving walkways are a primary form of high-speed public transportation.

For me, Heinlein's The Roads Must Roll immediately sprung to mind. That had 100 mph rolling roads, although glass partitions prevented high-fives (and wind shear).

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Re: 1175:"Moving Sidewalks"

Postby trakof » Mon Feb 18, 2013 7:22 am UTC

TimXCampbell wrote:I've heard that a person walks at an average of 2.5 miles per hour. Let's knock that down to 2 because of the concentration it would take to negotiate the speed changes. That means that at the High Five point both people will be travelling at 6x2=12 miles per hour, meaning that even if they keep their hands stationary they'll slap palms at 24 mph.

Hmm. If I was driving my motorcycle at 24 mph, would I want to slap a tree? I don't think I would.


That's a myth, the hit would still only be 12mph.

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Re: 1175:"Moving Sidewalks"

Postby phlip » Mon Feb 18, 2013 7:27 am UTC

Right... it'd be more like going 24mph and hitting someone's stationary hand, not going 24mph and hitting something more solid like a tree. A hand has a lot more give to it.
The impact is much closer to going 12mph and hitting something like a tree, which is significantly more rigid than a hand. This still probably wouldn't be fun, though.

Not that it matters, since the moving platforms are actually moving the other way, and they're having to run against the treadmill (for this to be possible, I would have to assume the "1x" speed is a lot slower than the 2mph you mention) to reach the middle and achieve high-five.

Code: Select all

enum ಠ_ಠ {°□°╰=1, °Д°╰, ಠ益ಠ╰};
void ┻━┻︵​╰(ಠ_ಠ ⚠) {exit((int)⚠);}
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Re: 1175:"Moving Sidewalks"

Postby Morinfen » Mon Feb 18, 2013 7:43 am UTC

TimXCampbell wrote:I've heard that a person walks at an average of 2.5 miles per hour. Let's knock that down to 2 because of the concentration it would take to negotiate the speed changes. That means that at the High Five point both people will be travelling at 6x2=12 miles per hour, meaning that even if they keep their hands stationary they'll slap palms at 24 mph.

Hmm. If I was driving my motorcycle at 24 mph, would I want to slap a tree? I don't think I would.


Why do you assume that the first conveyor belt moves at the average human walking speed? Usually conveyor belts move much slower than that.

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Re: 1175:"Moving Sidewalks"

Postby Mikeski » Mon Feb 18, 2013 8:02 am UTC

I think I could spend hours just stepping on and of conveyor belts moving at various speeds.

Okay. Go.

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Re: 1175:"Moving Sidewalks"

Postby Ryxis » Mon Feb 18, 2013 8:10 am UTC

What kind of sick person high fives with their left hand?

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Re: 1175:"Moving Sidewalks"

Postby phlip » Mon Feb 18, 2013 8:27 am UTC

Ryxis wrote:What kind of sick person high fives with their left hand?

... They're not?

Code: Select all

enum ಠ_ಠ {°□°╰=1, °Д°╰, ಠ益ಠ╰};
void ┻━┻︵​╰(ಠ_ಠ ⚠) {exit((int)⚠);}
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Re: 1175:"Moving Sidewalks"

Postby Istaro » Mon Feb 18, 2013 8:49 am UTC

phlip wrote:
Ryxis wrote:What kind of sick person high fives with their left hand?

... They're not?


Right, surely they're not, which serves as further confirmation that

Admiralz wrote:It may just be the perspective, but each person seems to be ready to jump onto an arrow facing back at them.
Does anyone think this is intentional or an oversight by the artist?


it's intentional.

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Re: 1175:"Moving Sidewalks"

Postby oliphaunt » Mon Feb 18, 2013 9:43 am UTC

Sandor wrote:
HagarTopeka1 wrote:This one reminds me of Asimov's The Caves of Steel, where moving walkways are a primary form of high-speed public transportation.

For me, Heinlein's The Roads Must Roll immediately sprung to mind. That had 100 mph rolling roads, although glass partitions prevented high-fives (and wind shear).

For me, too. Nice story, that.
ylno thgir ot tfel morf txet siht daer esaelp

tjunction
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Re: 1175:"Moving Sidewalks"

Postby tjunction » Mon Feb 18, 2013 9:53 am UTC

phlip wrote:Right... it'd be more like going 24mph and hitting someone's stationary hand, not going 24mph and hitting something more solid like a tree


Why?

The belts are moving towards the person, not away from them - so it is more akin to running on a treadmill. You just have to outrun each treadmill section to get to the middle. We can probably assume that by the time they high-five they're both running about the same speed as the middle section of the belt, i.e. they are basically stationary relative to the ground.

If you are running on a treadmill, and you high-five someone stading next to the treadmill, the impact is no greater than if the person on the treadmill were standing still on the floor. (Their feet may be moving at X mph relative to the belt, but their upper body isn't really moving at all relative to the floor).

If you set up two treadmills, facing opposite directions, and had two people running on them high-five each other, the same principle would hold.

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Re: 1175:"Moving Sidewalks"

Postby phlip » Mon Feb 18, 2013 9:54 am UTC

I was talking about the situation in the post I was replying to, in which they're standing on treadmills moving toward each other (at quite high speeds). As I went on to say in that same post:
phlip wrote:Not that it matters, since the moving platforms are actually moving the other way, and they're having to run against the treadmill (for this to be possible, I would have to assume the "1x" speed is a lot slower than the 2mph you mention) to reach the middle and achieve high-five.

Code: Select all

enum ಠ_ಠ {°□°╰=1, °Д°╰, ಠ益ಠ╰};
void ┻━┻︵​╰(ಠ_ಠ ⚠) {exit((int)⚠);}
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Re: 1175:"Moving Sidewalks"

Postby benhowt » Mon Feb 18, 2013 10:25 am UTC

phlip wrote:Not that it matters, since the moving platforms are actually moving the other way, and they're having to run against the treadmill (for this to be possible, I would have to assume the "1x" speed is a lot slower than the 2mph you mention) to reach the middle and achieve high-five.


Although it's very possible to run at 12 mph for short amounts of time. The high five would be slow, granted.

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Re: 1175:"Moving Sidewalks"

Postby aurizon » Mon Feb 18, 2013 11:07 am UTC

Why not a river of quicksilver, of variable depth (1 foot to 10 feet deep) and constant width and people ride in boats with dragfins so they stay at stream speed and do not over-run, and with collapsible rolls of material connecting the ends to allow for speed changes and with the mercury surface covered with solicone oil to block evaporation - could these be made into a continuous bi-directional closed travel conduit, with isolated channels to run in (no high five possible) and large ten foot deep open conduit circular areas at each end to allow travellers to get off. The boats would travel the round area at 2-3 mph, and in the shallow areas they would go at 20-30 mph. Wind in the closed conduit would be reduced by fron and rear baffles.
A unit like this would need only pumps to create flow. The high density of the mercury would reduce ripples and the silicone oil would stop mercury vapor from getting into the air.
Conventional horizontal moving sidewalks also work, but are mechanically intensive and require a number of traverses to change speed, of the increment is 2.5 MPH to go to 25 MPH = 10 up and 10 down traverses = mechanical monstrosity .

In time all subways will be like the BART, no drivers, enter and exit from opposite sides. Currently in Toronto the badly designed subway enteres and exits from the same side = very slow in rush hour versus opposite side entry like BART. and the unions require a driver and a doorman for each train = high wage costs

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Re: 1175:"Moving Sidewalks"

Postby Red Hal » Mon Feb 18, 2013 11:24 am UTC

tjunction wrote:
phlip wrote:Right... it'd be more like going 24mph and hitting someone's stationary hand, not going 24mph and hitting something more solid like a tree


Why?

The belts are moving towards the person, not away from them - so it is more akin to running on a treadmill. You just have to outrun each treadmill section to get to the middle. We can probably assume that by the time they high-five they're both running about the same speed as the middle section of the belt, i.e. they are basically stationary relative to the ground.

If you are running on a treadmill, and you high-five someone stading next to the treadmill, the impact is no greater than if the person on the treadmill were standing still on the floor. (Their feet may be moving at X mph relative to the belt, but their upper body isn't really moving at all relative to the floor).

If you set up two treadmills, facing opposite directions, and had two people running on them high-five each other, the same principle would hold.
That's all very well, but will they take off or not?
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Re: 1175:"Moving Sidewalks"

Postby J L » Mon Feb 18, 2013 11:35 am UTC

bitwiseshiftleft wrote:... and this is why I like Robo Rally.

Good for them there are no lasers or crushers on this conveyor belt!

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Re: 1175:"Moving Sidewalks"

Postby Don Calvus » Mon Feb 18, 2013 11:55 am UTC

Admiralz wrote:It may just be the perspective, but each person seems to be ready to jump onto an arrow facing back at them.
Does anyone think this is intentional or an oversight by the artist?
Because it would seem as if they are taking the intentionally hard (becoming quickly harder) route to that high-five.


Sometimes I get scared.

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Re: 1175:"Moving Sidewalks"

Postby ludarp » Mon Feb 18, 2013 12:08 pm UTC

I'm surprised at the number of failed attempts of High Speed Walkways (See Moving_walkway#High-speed_walkways on wikipedia) ... Clearly there's unacceptable danger on multispeed platforms when you stand directly on the bits going at different speeds / directions.

I've often thought: why not have little caged platforms that people can step into, where the entire platform then accelerates - basically like a gondola car running at ground level. There could be multiple entry points, where the platforms could "zip together" to increase capacity of the high-speed line. Too complex/uneconomic/space-consuming I guess... but would be super cool.
Last edited by ludarp on Mon Feb 18, 2013 12:37 pm UTC, edited 1 time in total.

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Re: 1175:"Moving Sidewalks"

Postby rmsgrey » Mon Feb 18, 2013 12:14 pm UTC

J L wrote:
bitwiseshiftleft wrote:... and this is why I like Robo Rally.

Good for them there are no lasers or crushers on this conveyor belt!


But there's no flag around either...

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Re: 1175:"Moving Sidewalks"

Postby Dr. Gamera » Mon Feb 18, 2013 12:25 pm UTC

Mikeski wrote:
I think I could spend hours just stepping on and of conveyor belts moving at various speeds.

Okay. Go.


Heh.

Joke explanation in spoiler.


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Re: 1175:"Moving Sidewalks"

Postby Vir4030 » Mon Feb 18, 2013 12:30 pm UTC

trakof wrote:That's a myth, the hit would still only be 12mph.


Not a chance. Two people moving towards each other at 12mph will hit with the same force as if one was moving at 24mph and the other was stationary.

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Re: 1175:"Moving Sidewalks"

Postby gerardw » Mon Feb 18, 2013 12:46 pm UTC

The faster belts should be longer to provide a more uniform acceleration.

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Re: 1175:"Moving Sidewalks"

Postby n079614 » Mon Feb 18, 2013 1:01 pm UTC

Arggh! Beaten to the OK Go punchline!

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Philbert
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Re: 1175:"Moving Sidewalks"

Postby Philbert » Mon Feb 18, 2013 1:10 pm UTC

HagarTopeka1 wrote:This one reminds me of Asimov's The Caves of Steel, where moving walkways are a primary form of high-speed public transportation.

I came to the forum to say just that. I read it a long time ago and I'm pretty vague on the story of the book in general, but those walkways always stuck in my head.

I think they would be a great means of transportation, though they seem difficult and expensive to engineer.

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Re: 1175:"Moving Sidewalks"

Postby Milnoc » Mon Feb 18, 2013 1:25 pm UTC

As mentioned before, the two individuals are lined up with the wrong conveyor.

Also, the egress arrow at both ends should be rotated to throw the individual on the opposing belt. Infinite High Fives!

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Re: 1175:"Moving Sidewalks"

Postby luvrhino » Mon Feb 18, 2013 1:57 pm UTC

My preference for innovation in ambulation is Improv Everywhere's concept of separate Tourist Lanes and New Yorker lanes so that lollygaggers can get out of my way:

http://improveverywhere.com/2010/06/08/ ... rist-lane/

As for the comic, In the United States, we walk on the right side of sidewalk/hallway, which means that either proficiency for left-handed high fives is required or an implicit agreement that everyone runs against the moving sidewalk.

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Re: 1175:"Moving Sidewalks"

Postby Someguy945 » Mon Feb 18, 2013 2:41 pm UTC

Check the header in the comic now:

Oops! I originally put up a version with backward sidewalk arrows.
I should know better than to edit and post comics while sleep-deprived. Sorry!

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Re: 1175:"Moving Sidewalks"

Postby Plutarch » Mon Feb 18, 2013 2:41 pm UTC

Admiralz wrote:It may just be the perspective, but each person seems to be ready to jump onto an arrow facing back at them.
Does anyone think this is intentional or an oversight by the artist?
Because it would seem as if they are taking the intentionally hard (becoming quickly harder) route to that high-five.


When I first looked at this, which was a few minutes after it was posted, it also seemed to me that the figures were about to leap onto the 'wrong way' conveyor belt, with the arrow facing back at them. But now they seem clearly to be heading onto the 'right way' belts, with the arrow pointing away. Either the picture has been altered, or I've imagined it. (Yes, 'I've imagined it' is more likely.)

edit - My post become meaningless due to another post sneaking in before me! Not sure of protocol here. Is this what being 'ninjad' means? Also realise I don't know how to make 'ninja' into a verb.

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Re: 1175:"Moving Sidewalks"

Postby CharlieP » Mon Feb 18, 2013 3:00 pm UTC

I'm surprised nobody's mentioned the high-speed walkways at the Montparnasse – Bienvenüe Paris Métro station:

From Wikipedia (as I'm not allowed to post links as a ZOMG n00b):

"At the end of the 1930s, a long corridor was built to connect the Montparnasse and Bienvenüe stations. Accordingly, the stations' names were fused to create the one now known as Montparnasse-Bienvenüe on 6 October 1942. This long corridor is now equipped with moving walkways to facilitate access between the two parts of the Métro station. The old Bienvenüe station serves lines 6 and 13, while the old Montparnasse station serves lines 4 and 12.

In 2002, in an experimental move, the RATP installed a moving walkway that moved at 12 km/h, which was then termed the "fastest in the world." (The speed has however been reduced to 9 km/h afterwards). The first several metres consist of metal rollers that accelerate passengers as they hold onto the handrail, because it would be dangerous to step directly onto the fast-moving conveyor. However, RATP announced in May 2009 that they would replace the walkway with an ordinary one in March 2011 in response to 'numerous customer complaints concerning safety and unreliability'."

Randall would have loved it...

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Re: 1175:"Moving Sidewalks"

Postby NiteClerk » Mon Feb 18, 2013 3:01 pm UTC

TimXCampbell wrote:I've heard that a person walks at an average of 2.5 miles per hour. Let's knock that down to 2 because of the concentration it would take to negotiate the speed changes. That means that at the High Five point both people will be travelling at 6x2=12 miles per hour, meaning that even if they keep their hands stationary they'll slap palms at 24 mph. Hmm. If I was driving my motorcycle at 24 mph, would I want to slap a tree? I don't think I would.


I took the speed increase as a relative increase. So assuming the first one is 2 mpg, the second is 4, third is 12, fourth is 48, fifth is 240, so at the high five impact the individual speed is 1,440 mpg.

Looking at the numbers written down I see that this is silly and would only be built by a government agency such as the Ministry of Silly Walks.

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Re: 1175:"Moving Sidewalks"

Postby luvrhino » Mon Feb 18, 2013 3:02 pm UTC

The arrows were correct the way it was for the United States. People walk on the right side in hallways and sidewalks.

As it appears that Mr. Munroe's intention was for the two to be going to on the correct direction, he should have moved them instead of the arrows.

Edited to Add: If this was a Ministry of Silly Walks project, then, yes, that would explain the left-sided flow of traffic, which conveniently allows for right-handed high-fives.
Last edited by luvrhino on Mon Feb 18, 2013 5:35 pm UTC, edited 1 time in total.


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