Phantom traffic jam on Storrow Drive

This morning, Jeannie Vincent reported a traffic jam on Storrow Drive that suddenly ended around Fenway with no evidence of an accident.

If she'd been across the river on Mem. Drive, she could have stopped into the MIT mathematics department, where some researchers spent a fair amount of time studying these phantom traffic jams - and the way they're caused by waves they've dubbed jamitons:

"We wanted to describe this using a mathematical model similar to that of fluid flow," said Kasimov, whose main research focus is detonation waves. He and his co-authors found that, like detonation waves, jamitons have a "sonic point," which separates the traffic flow into upstream and downstream components. Much like the event horizon of a black hole, the sonic point precludes communication between these distinct components so that, for example, information about free-flowing conditions just beyond the front of the jam can't reach drivers behind the sonic point. As a result, drivers stuck in dense traffic may have no idea that the jam has no external cause, such as an accident or other bottleneck. Correspondingly, they don't appreciate that traffic conditions are soon to improve and drive accordingly.

"You're stuck in traffic until all of the sudden it just clears," says Morris.

Jamitons in more detail.