All aboard!

Crowd dynamics seen in public transportation like trains fascinate me. Like I was mentioning to Sharon the other day, in Singapore, one can see a very strange phenomenon when the train stops and people want to get out, and some want to get in. I'm sure this is not exclusive to the MRT, the trains in busy cities elsewhere probably are similar. The situation is like this. When the train stops, those that are outside should do what? They should stand aside and let the folks inside alight first, correct or not? But for some interesting reason, many do not, so the authorities draw yellow lines on the ground to emphasize that point. So fair enough, people get the idea; and will try to stand away from the doors when the train stops. Then a second funny thing happens. Those that are outside will wait for some of the people inside to get out. And they will squeeze into the train before everyone has the chance to get out. If you're still inside, you need to push your way out! (Insert Batman punch!pow!wham! speech balloons here.) Assuming the width of a person to be one quarter the width of the door, two people doing this will mean that the volume of movement per unit time gets cut by 50%. Obviously, this is a serious matter that can't be ignored. So I've thought about this for a long time. Why do people do this? Isn't it reasonable for someone outside to wait for the folks inside to get out first? What is the motivation for this? My original feeling is that for the person outside, the rational thought process that tells us that's it's more efficient to wait is secondary to the primary objective: to get in first. Now why do people want to get in first? Well, maybe they want a seat. I had the chance to observe a different setup a few days ago. I took the train back to Perth, and almost everyone alighted, and there were lots of people wanting to get in. So I decided to see if there's anything different. Firstly, there's a huge crowd outside, four lines deep, and they automatically parted like the Red Sea when the doors opened. I went out and stayed behind to watch. Do they try to get in before everyone got out? Interestingly, they didn't. It was a smooth transition between the flow of people going out, and then going in. So the big question I have is again, why?! The crowd sizes in the two scenarios were both large. It was a weekday, not a unbusy weekend. So these two situational variables were quite similar. So what might have accounted for the differences? I think it boils down to the motivation I mentioned. The whole idea is to get the seats. And the corollary is true: the probability of success in getting the seat is directly dependant on the aggressiveness of the fellow passengers! So it's actually a hard-fought struggle, against each other! That's why people wanna rush in before it's too late! But why isn't that thinking seen in the Perth train? Because the motivation is quite different. It's not that urgent to get a seat, I think. The race just isn't quite there. And this is related to another cultural difference: in Singapore, if there's a queue, just join it! Ask questions later. The idea is that if there's anything to be had (including train seats), grab it! There's this time I actually asked someone who's in this very long queue whether he knew what he's queueing up for, and he said he had no idea, so I can see how this can happen. So what's the antidote for this? I'm not saying there's anything inherently wrong with rushing for seats since everyone has understandably very tired legs. But maybe everyone can have a better quality of life and be kinder to one another if those who don't need a seat let those who need it more have it, and to see it as an unnecessary race, if they can afford to. In reality though, it's very difficult to do. The situational forces will more than overide any sense of common sense... Note that I only have a sample size of one, so this must be taken with a pinch of salt. I'd be interested in observations from places like say Japan where you can be in a train and everyone is squeezing you so tightly, the lateral forces are able to physically move you from place to place. Not exactly my idea of fun though...