McKinsey & Company has an interview question: Are there more gates at the entrance of the subway, or more gates at the exit? Theoretically, as many people come in as there are people going out of a subway station, there should be the same number of turnstiles. But the reality is that there are many gates for export. why?
On the one hand, you can regard the subway station as a closed space, and the speed of evacuation is definitely more important than the speed of entry. Because evacuation is directly about safety, access is only about efficiency. Safety takes priority over efficiency.
There is another reason: the flow of people at the entrance comes one after another, just fluctuating smoothly. But the flow of people at the exit, as a car arrives at the station, is a surge, and the flow of people will increase in an instant, so there should be more exit gates.
This is the continuous revision of the theoretical world by the real world. I think there must be the same number of designs for subway stations at the beginning. Such optimization opportunities are actually everywhere. For example, in recent years, women's restrooms have been designed to be larger than men's restrooms, which is also a late optimization.
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