Originally Posted By: James_Van_Artsdalen
The Lunar New Year migration in China has several individual train stations seeing departures of over a million people over a few days. Change "departures" to "evacuation" and I see no reason they couldn't do a million+ population city.

Well, carrying capacity is all relative to the population. Almost a million commuters travel into just Manhattan a day, but how well could they evacuate all 8 million in a short period of time? Not very well. Super-efficient Tokyo moves almost 10 million commuters a day. Even the antiquated, overloaded system in Mumbai, India moves something like 8 million commuters a day. But neither city--megacity, really--could evacuate every resident without a lot of problems since the transportation system doesn't have such massive carrying capacity.