Lots of traffic, little data

Los Angeles' traffic signal system is the envy of traffic planners around the world, recording millions of cars each year as they pass over sensors embedded in city streets.

The data beep and shine on screens in a state-of-the-art traffic control center that looks like something out of a science fiction movie. The information -- Wilshire Boulevard jammed in Westwood, Broadway wide-open through downtown -- is used to adjust the timing of traffic lights, easing the flow of vehicles through the city's busy streets. The data are instantly placed on the Internet, available to commuters and traffic reporters.

But although the sensors and computers collect massive amounts of data about traffic patterns and congestion, they do little to help engineers plan for the city's growing transportation needs -- or determine how development is affecting traffic.

That's because the city does not save the information for more than a few days, using it only to direct traffic in real time by adjusting the speed at which lights turn from green to amber to red.

Because the information is discarded, it cannot be used to determine over time where traffic is increasing -- or by how much.

In fact, city officials said they don't have traffic counts for some of the city's busiest intersections -- and can't say how much congestion has increased over the years

The lack of traffic data is becoming more of a vexing issue at City Hall and in L.A. neighborhoods, especially in the midst of a building boom that has increased both residential and office development.

And it will probably be on the agenda for the new head of the Los Angeles Department of Transportation, Rita Robinson, who until last week was the city's sanitation director. The former chief, Gloria Jeff, was fired by Mayor Antonio Villaraigosa on Friday. Jeff's ouster came after months of grumbling that the department was slow in making improvements aimed at lessening worsening street congestion.

Many at City Hall believe getting better traffic data is crucial.

"It's appalling," said Councilwoman Wendy Greuel. The chronic lack of information makes it impossible to determine "where density should go and where it shouldn't go."

Consider Hollywood.

Over the last decade, several huge developments have been built, including the Hollywood & Highland shopping center, the ArcLight movie theater and the W Hotel complex at Hollywood and Vine, a mixed-used project now rising at the famous intersection.

But city officials said that they don't know how much the boom has affected traffic, because there is little historical data.

City codes require developers to produce a traffic study before building a new project, and city traffic engineers conduct a count of surrounding streets at that time.

But the developer and city traffic planners generally are not required to follow that up with updated counts after the project goes in.

As a result, planners might know how much traffic an area had before a development was built, but not afterward.

"One of the challenges that the city of Los Angeles has had over the years is that they have reduced the staffing that's been available to do data collection," said Jeff in an interview before her dismissal. Although Jeff was politic in her description of the problem, an aide said that the former Michigan official had been shocked when she arrived two years ago at how little information Los Angeles gathered about traffic.

Bill Reichmuth, transportation chairman for the American Public Works Assn. and a top traffic planner in Monterey, Calif., said planners in built-out cities like Los Angeles need such historical data to decide how large redevelopment projects should be, and where they should go.

"If you don't have it, you're hamstrung," Reichmuth said. "Without that data, you've got no way to make those kinds of assessments."

City Council President Eric Garcetti said it would cost about $1 million to start organizing and archiving data from the city's traffic control system.