The survey by Rice University political scientist Bob Stein shows many people in non-evacuation areas evacuated anyway, and instead of listening to media reports or requests by public officials to stay put, listened to their friends and neighbors instead.
"We show a statistical model that really is quite devastating. The influence of friends and neighbors on the decision to evacuate is two-and-a-half times greater than Mayor White, weather people and public announcements."
The survey includes input from 650 people in the 8-county Houston-area who evacuated as Rita approached the Texas Gulf Coast. Stein says a bandwagon effect clogged Houston's freeways at the worst time.
"What happened in non-evacuation areas is that people reported to us that they saw more and more of their neighbors leaving and there was a point at which you went from some to many to all that everybody else in the neighborhood left and that seems for us to be the working hypothesis."
Stein says a change in who people listen to in times of crisis might be the quickest and most effective way of ensuring an orderly evacuation the next time a storm threatens the Houston area.
"47-percent of the people we surveyed in non-evacuation areas left. If we could just change when they left and we can do it with just getting them to shift from listening to their neighbors to the mayor, to the weather people, we probably can abate a significant portion of the congestion."
He says evacuating by zip code, rather than large regional zones, might be a more effective way of avoiding gridlock. There are estimates that more than 2 million people tried to leave Houston as Rita approached.