FutureStructure

California Fights Road Expansions in the Face of a Growing Populace

The state Department of Transportation has decided to focus on existing roads instead of expansions, citing research that shows increasing the number of lanes only adds more traffic.

by / December 1, 2015

The California Department of Transportation has decided that as the state’s population grows, it might be a bad idea to build more roads to accommodate the new residents.

That’s the news from The Sacramento Bee, which reported last week that the department is prioritizing maintenance of existing roads above expansions and new roads. It’s a reflection of a culture shift CalTrans has been touting for a while now — latching onto Gov. Jerry Brown’s environmental policies, the department is now whole-heartedly embracing a concept it previously dismissed.

The concept is called “induced travel.” It’s a marriage of economic theory with urban planning, and more or less says that if a government expands a clogged highway or builds more streets, more drivers will rush in to fill that space. That means no reduced congestion.

Induced travel has been getting a lot of play in California lately, with CalTrans embracing the idea in its January 2014 State Smart Transportation Initiative report outlining its future direction. Susan Handy, a professor in the University of California, Davis, Department of Environmental Science and Policy, published a white paper in October explaining the concept amid debates about transportation funding at the state Legislature.

The idea was featured prominently this year in analyses of a few high-profile transportation projects that were meant to help Los Angeles with its notoriously congested traffic. One was a study from the private firm INRIX, finding that a four-year, $1 billion expansion of Interstate 405 failed to improve traffic times. The other was a study from the University of Southern California looking at the impacts a new light rail line from downtown to Culver City following Interstate 10 had on traffic.

Consistent with the principal of induced travel, the study found that ridership on public transit increased along the corridor, but it didn’t do much to reduce the number of cars on I-10.

“This is all about latent demand, meaning that if you introduce a new rail line, of course there will be some redistribution,” said Sandip Chakrabarti, co-author of the study. “So people will shift from bus to rail, and people have shifted from bus to rail … and people have moved from cars to rail and there have been new trips on rail.”

The same thing happens on highways — create a new lane, and more people overall will drive on the road. That’s a problem for a department whose goals now include reducing greenhouse gas emissions from transportation. So instead of funding expansions and new roads, one of CalTrans’ new goals is to encourage multi-modal transportation, including biking and walking.

Another big theme the department has been discussing is efficient land use. In her white paper, Handy pointed to an example where removing roads — freeway segments in San Francisco — actually led to less traffic and a revitalization of neighborhoods in those areas.

It all comes back to efficiency.

“The quality of our mobility decisions contributes to economic prosperity by enhancing the safe and efficient movement of people, goods, and services,” CalTrans’ Strategic Management Plan reads. “Investments in the state’s transportation infrastructure provide significant economic returns, preserve ecological health, contribute to climate change resilient systems, and create conditions that attract businesses and employers to local communities.”