odd things I post on facebook
 

Pedestrians moving in a stream require average areas of 24.73 square feet (2.297 square
meters) per person to attain normal walking speed, and to pass and avoid others.
At 10 square feet (0.929 square meters) per person, walking becomes significantly
restricted, and speeds noticeably reduced.
At 4.95 square feet (0.46 square meters) per person, the maximum capacity of a corridor
or walkway is attained with movement at a shuffling gait and movement possible only as
a group. This would be characteristic of a group exiting a stadium or theater.
At less than 4.95 square feet (0.46 square meters) per person average, individual
pedestrian mobility becomes increasingly restricted.
At approximately 3 square feet (0.2787 square meters) per person, involuntary contact
and brushing against others occurs. This is a behavioral threshold generally avoided by
the public, except in crowded elevators and buses.
Below 2 square feet (0.1858 square meters) per person, potentially dangerous crowd
forces and psychological pressures begin to develop.