You Do the Math

    Next time you're stuck on the freeway think of waves radiating outward from a gas explosion.

    August 27, 2010

    Next time you finally extricate yourself from a freeway traffic jam only to discover no known cause for the snarl-up, think of waves radiating outwards from a gas explosion. U of A mechanical engineering professor Morris Flynn, ’00 BSc(ChemEng), ’03 MSc, did, and won 39th place on Discover magazine’s “Top 100 Stories of 2009.”

    Flynn’s theoretical paper, published in the American Physical Society Physical Review E, compared traffic jams with exploding gases and found that “when you look at traffic jams mathematically, it’s very similar to the detonation waves that radiate outwards from the ignition point of an exploding gas.” The complicated mathematical model devised by Flynn and his research team likens the effect of the exploding gas to that of one driver hitting the brakes lightly, thus causing a chain reaction in the drivers following the braking driver resulting in successive waves of slower and slower vehicles.

    But why a theoretical paper devoted to traffic jams? As the paper, titled “Self-sustained nonlinear waves in traffic flow,” states: “The economic costs in terms of lost productivity, atmospheric pollution, and vehicular collisions associated with traffic jams are substantial both in developed and developing nations.”

    Flynn points out that the best way to prevent phantom traffic jams is to understand their patterns and timing, and says, “I think the key is to let freeway drivers know what’s happening up ahead. With the proliferation of GPS units in vehicles today, authorities could send out warnings and suggest alternative routes.”

    For the complete paper go to: and look up volume 79, article 56113.