John J. Fruin is an engineer, urban planner, and author known for his work in the field of crowd science.
[3][4] He attended Polytechnic Institute of Brooklyn, where he received his M.C.E, M.S., and PhD degrees.
[4] He evaluated personal comfort zones of individuals in different situations, which is affected by national culture, the degree to which people are intimate with one another, mental health, and other factors.
[4] Now retired, he was formerly employed as a research engineer by the Port Authority of New York and New Jersey.
[8] Fruin married fellow Brooklyn resident, Rita Murray, in the spring of 1952.