The Breakdown

Explaining Southern California's economy

405 traffic: A little slower after $1 billion upgrade

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Transit agencies spent five years and more than a billion dollars improving a stretch of the 405 freeway, in a massive project that gave us the term "Carmageddon" as crews shut down the freeway to complete upgrades. But now, after opening one of the main achievements - a ten-mile carpool lane - it doesn't appear that traffic is moving any faster during rush hour.  In fact, one study suggests travel times have slowed a bit following all of the construction - by about a minute. 

INRIX, a traffic analysis firm, examined the Northbound 405 between the 10 and 101 freeways, from 4 p.m. to 7 p.m.  The study compared travel times from the middle two weeks of September, 2013 (with only a 1.7 mile stretch of the carpool lane open) to the same period this year (with the full 10-mile carpool lane in service for nearly five months.) The average travel time this September was 35 minutes, roughly a minute slower than last September. 

405 NB Travel Time Rush hour

There was some good news from INRIX. The worst congestion of rush hour appears to be ending earlier.  A year ago, the average travel time from 7 p.m. to 8 p.m. on the northbound stretch was 28  minutes. Now, it's down to 22 minutes, according to Jim Bak, a director of INRIX in Kirkland, Washington. 

"While travel times in the peak of rush hour - 5 p.m. to 6 p.m. have not gotten better or marginally worse, we are seeing travel times getting better towards the tail end of the rush hour period," Bak told KPCC. 

For Bak, the early data does not suggest that the carpool lane was a waste of money, but a reminder that there is no silver bullet solution to traffic congestion. He also sees a link between increased congestion and improvement in the economy.

"When our economy recovers, I like to say, 'as GDP goes up, MPH goes down,'" Bak said, adding that more Southern Californians are going to work and then going out to spend the money they're earning.  "The reality is that if they hadn't added that lane on the 405, we would probably see travel times that are much worse right now than what we're seeing, because what's happening out there is our economy is getting better." 

Bak says Los Angeles is an example of trend he's seeing nationwide - traffic congestion is growing at three times the rate of GDP. 

Dave Sotero, a spokesman for the Los Angeles Metropolitan Transportation Authority, says the Sepulveda Pass improvement projects were never expected to eliminate traffic congestion completely.    

“You can’t escape the fact that carpool lanes are going to fill up during peak periods,” Sotero commented in the blog of L.A. County Supervisor Zev Yaroslavsky.  “What carpool lanes do is reduce the duration and severity of traffic.”

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