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Why the 405 isn't any faster with more lanes

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LOS ANGELES, CA - JULY 17: Light traffic flows on the Interstate 405 after it re-opened ahead of schedule following the10 mile shutdown of the nation's busiest freeway for bridge work the Mulholland bridge on July 17, 2011 in Los Angeles, California. Los Angeles city officials advised residents to stay home or stay away from the area over the weekend fearing massive traffic jams of what has become known as ''Carmageddon.'' which never materialized. (Photo by Kevork Djansezian/Getty Images)
Kevork Djansezian/Getty Images
Light traffic flows on the Interstate 405 after it re-opened ahead of schedule following the 10-mile shutdown of the nation's busiest freeway for bridge work the Mulholland bridge on July 17, 2011 in Los Angeles, California.

Increase the number of roads out there and drivers think it's less crowded. But once they head out, the roads get just as clogged as they were before.

Maybe you thought Carmageddon and Jamzilla were worth it: trade in weeks and months of pain on the freeway so that new lanes could be constructed, and that would make traffic better for years to come, right?

But your commute says otherwise.

Drivers on the 405 spent about one minute more in traffic than last year despite the addition of a new carpool lane.

That outcome is probably not surprising to economist Matthew Turner.

Turner co-authored a study that showed a one-to-one correlation in road capacity and the amount of drivers on the road.

"There's a lot of trips that you don't take because you don't want to drive when it's congested," he says, "and if it's little bit less congested there's a lot of trips people are willing to take."

Increase the number of roads out there and drivers think it's less crowded. But once they head out, the roads get just as clogged as they were before.

And mass transit isn't an answer either, he says.

"If you take people off the road for transit, then you expect other people will drive," says Turner. "So these transit projects are good for moving people around, but you should not think of them as solutions to the problem of congestion."

Turner says he's only encountered one tactic that successfully tackles that problem: congestion pricing.

In Los Angeles, it's already in effect on the 10 and 110

"If you charge people to get on the road, they will change their behavior so they get on the road at less congested times," he says.

Turner says it's worked well in Stockholm, London and Singapore. 

In the meantime, you'll have to settle for tuning into your favorite radio station (like SCPR!) as you slowly chug along in your car.

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