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USC study finds no lessening of traffic with Expo Line

FILE: An Expo Line train heads out of Farmdale Station heading for Culver City.
FILE: An Expo Line train heads out of Farmdale Station heading for Culver City.
Sharon McNary/KPCC

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A new University of Southern California study has found the $980 million Expo Line failed to reduce traffic on the adjacent I-10 Freeway.

The study published in the Journal of Planning, Education and Research adds to studies that suggest urban rail projects, even when effective, aren't likely to reduce car traffic congestion.

The researchers used sensors along the freeway and arterial roads over three months and concluded the first phase of the Expo Line from downtown to Culver City had little to any impact on congestion on the freeways or local streets.

Reducing traffic congestion and providing traffic relief are favorite benefits touted by officials to win support for expensive transit projects like the Expo Line.

At a press preview for the second phase of the Expo Line to Santa Monica in June, Los Angeles Mayor Eric Garcetti said: ‘The Expo Line will carry over 64,000 riders each day, which provides traffic relief.”

The mayor's office did not immediately return a request for comment.

The study authors said the marketing of transit projects overlooks other valid reasons for supporting public transportation efforts.

The study found a "significant overall rise in transit ridership" on the downtown-Culver City corridor along the Expo Line. The authors point out this improves productivity and travel opportunities for many low-income people or those who can't drive due to physical limitations.

Metro Transportation Authority spokesman Rick Jager also stressed that those who use public transit like the Expo Line do get relief from packed roadways.

“All of our projects are viable transportation alternatives and are providing thousands of commuters relief from mobility congestion in the region and improving the quality of life,” he said.

Transportation planners have long observed a phenomenon of transit construction: that when you build more transit lines or bigger freeways, there's initial improvement in road congestion, but that actually encourages more drivers to take road trips they might have avoided or taken by other means. 

The USC study is the first to emerge from a "big data" archive run by the university and designed to help transportation officials make science-based decisions on taxpayer-funded projects.

The study's authors include Genevieve Giuliano, chair of Effective Local Government at the USC Sol Price School of Public Policy; Sandip Chakrabarti, a post-doctoral researcher at METRANS Transportation Center, a partnership between USC and California State University, Long Beach; and Mohja Rhoads of South Bay Cities Council of Governments. The study was funded in part by L.A. County Metro.

“Looking into the future, this study shows us how to be more realistic in what we should expect from transit,” said Chakrabarti.