Reported January 2008

THE PHYSICS OF TRAFFIC: Conventional scientific wisdom compares traffic jams to the process of freezing, where a flowing liquid turns into a solid. On a sparsely populated highway the cars are far apart and can move at whatever speed they choose while freely moving between lanes -- much like the molecules in a gas. In heavier traffic, the cars are more densely packed with less room to maneuver, so cars move at slower average speeds and traffic behaves more like a liquid. If the cars become too densely packed, their speed is reduced, and their movement restricted, to such an extent that they almost stop moving altogether and form a "solid" expanse of traffic, "freezing" into ice.

If you would like more information, please contact:

Richard W. Backs, Ph.D.
Professor of Psychology
Central Michigan University
Mount Pleasant, MI 48859
(989) 774-6497
backs1rw@cmich.edu