# Escalators: Stand right, walk left. When can this rule be ignored?

On my daily commute to work, I find a sign on all escalators, stating

Stand right, walk left

The idea behind this, obviously, is that you should leave space for people in a hurry, so they can run up the escalator and catch the train, while the majority of people just waits until they're transported to the top.

I have the gut feeling that this rule is not valid in all cases, ie. depending on the amount of people who want to use said escalator. I think that when there are a lot of people, even those in a hurry would be better off if this rule would be (temporarily) ignored by everybody, since the waiting time before the escalator can be reduced.

Now, the question is this: Given a few assumptions, where is the tipping point to use the full escalator width (which, by the way would have space for two rows of people)?

According to my observations, I think we could assume the following things:

• The ratio of people in a hurry is around 5 percent
• There is space for two people next to each other. So we have either two rows of people standing, or one row (half capacity), leaving space for the "runners"
• People who are in a hurry roughly double their speed up the escalator
• When the number of people in the queue at the foot of the staircase is greater than 11 percent more than the number of stairs. – p.s. Jan 24 '12 at 3:47