Study looks to find reason behind phantom jams

WASHINGTON - You're crawling in super-slow traffic for no apparent reason, and all of a sudden the jam clears.

Don't you hate when that happens?

Some people call them phantom traffic jams because they appear and vanish like ghosts. But WTOP traffic guru Bob Marbourg says the term is misleading.

"For the person who's not able to travel at the speed limit, the delays are very real," says Marbourg.

Researchers at the Massachusetts Institute of Technology are studying how phantom jams are formed, and how they might be prevented. They found once such a jam begins, sometimes by a single driver not paying attention, it's almost impossible to break up.

In the long term, the MIT team says adding road capacity may help. But Marbourg says it's not that simple.

"Every time we eliminate a bottleneck, we identify the next bottleneck downstream."

In the short term, every driver can do something. "In many cases we could unravel the delays if only we'd play nice out on the highways," Marbourg says.

MIT plans to look more closely how the number of lanes on a particular road affects phantom jams.

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