Comment by davidmurdoch | Hacker News Reader

Comment by davidmurdoch | Hacker News Reader

American (US) in Tokyo for the first time here. About an hour ago (10:30 pm here) I saw two men with a bucket and washcloth scrubbing the floor right next to Shibuya Crossing ("the busiest crosswalk on the world"). Moments before that a man was sweeping a walkway between passer-bys). The clothing store withers swept each changing room in between guests. Though a block away was the smoking area, littered with thousands of cigarette butts (not sure what conclusion to draw about smokers).

I was in Osaka earlier in the week, and Kyoto after that. And these cities were also quite clean and orderly, with Osaka being the most orderly (and much more relaxed and slow paced, which makes order easier).

One of my favorite parts of Japan's cleanliness is their cars. They are all sparkling. Even the delivery trucks are shiny and splatter free! The gas/petrol station near me had at least two attendeds at each car, one to pump, and the other to clean the car's windows and paint!

Another fascinating thing is how escalators have two lanes, one for walking and one for standing. Why doesn't everyone so this?! It's so perfect!

Others in this thread don't speak too highly of Osaka, but it was definitely the most orderly and trash free of the three cities I've visited. Of course, these cities are quite huge, compared to cities in the US, so perhaps these conversations should be more fine grained, generalizing by prefecture rather than city.

I've found that I've been lining my things up neatly, and organizing my clothes and toiletries here in my in my hotel. It's been inspiring to see all the order here.

> Another fascinating thing is how escalators have two lanes, one for walking and one for standing. Why doesn't everyone so this?! It's so perfect!

I wish they'd just draw lines on escalators in Germany already. Keeping the left side of the escalator free and standing on the right is an unwritten rule here, but about one in twenty stand on the left anyways (tourists? people lost in thought?).

In the morning I often want to catch a connecting train that departs only about minute later, and pretty much every time I have to ask one or two people to step aside so I can pass. The fastest way to reach the other platform happens to be by means of two escalators. Other people who have been to Berlin Friedrichstraße station probably know which escalators I'm talking about.

The fastest way I have found of getting people to step aside is startling them with a firm "SORRY!" - works on tourists as well as Germans.

When I see more than three people on the left side I usually just give up though. By the time they'll have sorted themselves out the train will probably be gone anyways and I don't fancy breaking into a sprint just to make up for the lost seconds. I'd rather suck it up and wait a few minutes for the next train while getting a coffee on the platform.

I guess what I'm saying is that something as simple as two lines on escalators can make a difference of ten minutes or more in the commute of some people.

> Another fascinating thing is how escalators have two lanes, one for walking and one for standing. Why doesn't everyone so this?! It's so perfect!

Turns out, strangely, that it actually reduces throughput compared to just having everyone stand. So not exactly perfect I guess.

But yea I agree in the general matter. When my MIL (a master organizer) visited Japan she thought that was great.

That's generally the custom in the US as well.

Where in the US have you seen this? I've never seen it happen!

It's not strictly observed but in San Francisco BART people generally stand to the right while walkers pass on the left.

EDIT: spelling

Super common in NYC. People will yell at you if you stand in the left lane on an escalator.

First random video I googled for nyc escalator shows this behavior: https://www.youtube.com/watch?v=zmCOjC_9Iyc

Europe too. It'd surprise me if it isn't more common than not, globally.

> Turns out, strangely, that it actually reduces throughput compared to just having everyone stand

Wait, what? How can this be true?

Imagine an escalator w/ both lanes filled with people just standing. Now imagine the left lane starts walking: clearly, higher throughput.

Now, maybe you're imagining a scenario where people don't want to walk. Now everyone stands on the right, and the left lane is completely empty. OK, now we've reduced throughput by half compared to "everyone standing".

So as we consider moving between the extremes of "no walkers" and "walker saturation", there will be some break-even point of throughput. And beyond that having a walking lane will be more efficient.

(Also, besides raw throughput, having a walking lane gives you a better "fastest possible traversal time", which is also valuable, for people in a hurry.)

My first reaction to learning this was also about the same, haha.

The issue with the "everyone starts walking" is the same reason why stationary cars are closer together than moving cars. If people walked with military trained precision you could get the same density and vastly higher throughput by walking. But for civilian strangers, it turns out two lanes of standing gives high enough density to trump the increased speed of walking, in terms of total throughput. I'm fairly certain there's even a study showing this. They tested it in london underground at least.

But yes, it's certainly better for the few walkers.

Ah, I didn't consider density, that's a good point!

Taking a look at the study you mention (linked in other comments), it seems like the escalators they studied were well to the "too few people want to walk" side of the curve to be efficient.

I wonder how close the break-even point is to the simple metric, "do you have to wait to enter on the right?"

Or thinking of the queue length for standers, clearly when the length is 0 allowing walking is more efficient (you've taken nothing away from the standers, and the walkers are more efficient). But there is some point where the stand-queue length, let's call it N, is big enough that the corresonding wait-time means overall throughput is lowered by allowing walking.

I think it would be quite reasonable to require standing in those situations.

So the rule could be something like, "stand on the right, walk on the left, unless there is a queue of more than N people waiting to stand on the right, in which case you may stand on the left." Easy right? ;-)

(I wonder if N would vary w/ escalator length? Intuitively, almost certainly. So we'd have to post signs next to each escalator w/ its individual stand-queue limit. :-)

That makes a lot of sense to me.

> Now, maybe you're imagining a scenario where people don't want to walk.

Agreed that this is an imagined scenario because people in a hurry will want to maximize their speed by walking/running up the escalator.

More importantly, people generally (I'm imagining) do not want to stand on the same escalator step as another person, especially if they are strangers to each other.

That means in a 2-lane standing escalator there will be breaks between people standing to the left or the right which, effectively, will turn a 2-lane standing-only escalator into a "1-lane" standing escalator.

That's actually how it should be. People should stand alternating left-right-left-... Not having one empty step in front/back of you is quite dangerous especially with packed escalator.

Standing people stand closer together than walking people. However, I think they should optimize for minimum annoyance, not maximum throughput. With a walking lane, there's lower latency for people willing to walk.

Transport for London experimented with this, and found higher overall throughput during rush hour with two standing lanes:

https://www.independent.co.uk/news/science/it-is-faster-to-s...

> Standing-only escalators had a "throughput" of up to 151 passengers per minute, while an escalator where commuters were still allowed to walk saw around 115.

Your thought experiment's completely right, but in real world circumstances, once an escalator is above a certain height, people rarely use the walking lane:

> But a 2002 study of escalator capacity on the Underground found that on machines such as those at Holborn, with a vertical height of 24 metres, only 40% would even contemplate it [walking up]. By encouraging their preference, TfL effectively halves the capacity of the escalator in question, and creates significantly more crowding below, slowing everyone down.

(from https://www.theguardian.com/uk-news/2016/jan/16/the-tube-at-... , which has a great graphic showing the two systems)

That’s in one place, which is a particular bottleneck. The general rule is that two lanes are better.

Transport for London should politely refrain from any statements like that, I believe. They hardly can allow people to enter the platform because there's no space to fit the crowd. There's sea of heads almost every morning in front of most popular stations' gates. Not because they have a gates issue, or any other unusual problem - they are just regulating flow that way. So, I'd kindly ask them start modernizing platforms to allow more throughput in the first place. Then let them experiment and play with statistics, by all means.

The volume of the escalator is reduced by greater than half, and the departure rate is a function of density, so reserving half of the escalator for people who want to depart slightly faster than others (in single file, with space) apparently doesn't overtake what a single, densely packed transit could carry.

The problem is that people who want to walk are limited in reality by how quickly the slowest person ahead of them is traveling as well as conventions that make it unlikely that people would get within 1 full step of the person in front of them, reducing the lane's volume to 1/3 (the step you're on plus the step you're taking + space) of the possible occupancy of the standing lane.

So I could definitely see that assertion being true.

Article on the London experiment: https://www.theguardian.com/uk-news/2016/jan/16/the-tube-at-...

It's a long escalator, so few people walk (40% according to the Guardian article). And then during rush hour there's a crowd in front of the escalator.

This blog post estimates walking is 26 seconds and standing is 40 seconds: https://www.capgemini.com/gb-en/2016/04/would-standing-on-th...

The optimal policy is to have everyone walk 2 abreast as densely as possible, so this about debating two suboptimal policies. Presumably if it was actually a problem they would just build another escalator.

It sounds to me that the walk/stand system is nice because it creates a priority queue. Some people would rather wait and stand than not wait and walk. The people who are in a hurry get to walk and not wait. If the norm was "always stand", the 40% of people who walk would be much more annoyed. Even when the escalator was only at 5% capacity, there would be enough side-by-side standers that they wouldn't be able to walk.

Even if it does reduce throughput, which from what I've seen comes in waves (after disembarking a train), the people who are okay standing there get to stand without being pushed, while those that are in a hurry get to hurry without pushing. Not everything has to be at max efficiency all the time, sometimes the optimal solution is relative.

I guess, that set up is optimized for latency and not throughput, which really makes sense.

Escalators having two lanes is a thing in tons of places. Generally the larger the city, the closer to the cbd you are, and the more rush hour it is, the more likely it is to be a thing that everyone does.

Each time I've been to Osaka it has been remarkably different than the other cities we traveled to in Japan. It may come down to timing. My wife and I have only visited Japan during times of Japanese festivals.

You might enjoy this: https://www.netflix.com/title/80209379

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