This reminds me of the example of the placement of a barrier at an exit to reduce the number of interactions to improve pedestrian flow http://www.gkstill.com/

This reminds me of the example of the placement of a barrier at an exit to reduce the number of interactions to improve pedestrian flow http://www.gkstill.com/CV/PhD/Chapter3.html http://www.gkstill.com/CV/PhD/Chapter3.html Scroll down to 3.5.3 Flow through a door. I can't find the original article I read years ago but it showed a large round barrier to be the most effective, and more than one barrier for larger numbers of people