3 tips for easing jams on travelator
Wednesday, December 28, 2016

This topic is always on my mind whenever I see a travelator in a crowded area. Finally decided to write about it probably because of the videos I've watched recently regarding traffic jams where they described something called the ripple effect.

This video does a good explanation of the problem with traffic and the idea is similar to what I'm going to talk about.

A little background information
I take the train to school everyday and there's a rather long travelator on the connector between the purple and yellow line (which I take). Whenever either train line arrives, a good portion of the commuters will alight and make a beeline for the connector. Unless I'm ahead of the pack, the travelator will always end up being jammed with humans and no one can walk freely on it.

The amount of people ain't the main reason for the jam, but the amount of people who don't know how traffic works causes it.

Here's an image I've drawn to illustrate the problem.

the moving speed is just an example

As you can see, the travelator is moving at 3 meters per second. Some people will to stand on the left hand side to facilitate people who want to move faster on the right hand side.

Person A and B is walking on the travelator at 4m/s, adding on to the 3m/s that the travelator is moving at, their net movement speed is 7m/s. When person B exits the travelator, he should walk at 7m/s so that person A would not bang into him. But since a typical person would not walk at nearly twice his speed, B continues walking at 4m/s.
Hence B exits the travelator at 4m/s.

Can you see the problem here?

Because B is only effectively +1m/s faster than the speed of the travelator, anybody who is walking more than 1m/s will eventually have to slow down, and by slowing down way too quickly, the people behind him have to slow down even faster and some even comes to a stop. The exact same ripple effect observed in vehicle traffic.

Even if B exits the travelator at 6m/s, it still means that the maximum available move speed of person A behind him is only 3m/s.

Of course this is only a problem when the amount of people on the travelator hits above a certain sweet spot; as long as the commuters are spread out it should not cause a jam. But during peak hours, do yourself and your friends a favour, follow these 3 simple tips to ease the jam on travelators!

1. Exit the travelator as fast as you can (faster than the net speed of your walking + travelator speed) or just clear out of the way.
2. If there's a jam infront, walk slowly. Don't walk fast and then get stuck and stand there, it makes the jam worse.
3. If you're a slow walker, just walk/stand on the left hand side it's not going to take that much longer.

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