What's the best cabin layout for aircraft evacuation?

The Federal Aviation Administration (FAA) requires that, in the event of an emergency, all airplane passengers must be able to evacuate any aircraft within a 90-second window. But is that a realistic requirement, particularly given the increasing number of elderly passengers who might need more time and assistance? According to a new paper published in the journal AIP Advances, it is not. Various simulated scenarios showed evacuation times significantly higher than the 90-second requirement.