USC Price School of Public Policy

Price study on Expo Line’s traffic impact wins planning journal’s best paper award

November 10, 2017

Expo Line

By Matthew Kredell

USC Price School of Public Policy Professor Genevieve Giuliano and two recent Ph.D. students were awarded the 2017 Chester Rapkin Award by the Association of Collegiate Schools of Planning (ACSP) for their work analyzing the LA Metro Expo Line’s impact on transit ridership and traffic. The annual award is given in recognition of the best paper in the Journal of Planning Education and Research (JPER).

Genevieve Giuliano

Genevieve Giuliano

The USC Price team won for their paper “Using Regional Archived Multimodal Transportation System Data for Policy Analysis: A Case Study of the LA Metro Expo Line.” The award committee noted that the work “masterfully connects academic research with the world of urban planning practice to address real and pressing questions while also contributing to scholarship through methodological innovations and new insights into transit planning impacts.”

“JPER is our flagship journal in planning, and it is wonderful that our work has been recognized by the academic planning community,” said Giuliano, who serves as director of the METRANS Transportation Center. “I am particularly pleased that my co-authors are recent Ph.D. students, as this award means a great deal for junior scholars.”

Innovative use of big data

Sandip Chakrabarti

Sandip Chakrabarti

Mohja Rhoads

The paper grew from the Archived Data Management System (ADMS), a big data archive research project that Giuliano developed with colleagues from the Viterbi School of Engineering. The project was funded by LA Metro. Then-doctoral students Sandip Chakrabarti and Mohja Rhoads were research assistants on that project and served as co-authors for the paper.

In looking for test cases to show how the data could be used in urban planning, Giuliano identified the Expo Line as an ideal subject.

“I was convinced that big data could be useful to urban planners in exploring questions that we could not otherwise explore,” Giuliano said. “This paper is an example. Although there is an enormous amount of literature on the impacts of new rail lines, there was not one paper that examined impacts on traffic. This is despite the fact that transit investments are often promoted as a way to reduce congestion.”

Using transit, freeway and arterial data, the researchers explored the impact of the Expo Line on transit ridership, freeway traffic and arterial traffic within the corridor it serves.

They found that a new rail line does not divert enough passengers from cars to make a significant difference. The researchers concluded that the benefits of rail transit investments include increasing transit accessibility and person throughput within high-demand corridors; however, the effects on roadway traffic are small and localized.

“Many U.S. cities are investing heavily in light rail, and Los Angeles Metro has embarked on a massive rail expansion program,” Chakrabarti said. “I hope our findings will help transit planners design better projects that increase transit patronage and meet objectives or expectations.”

Ongoing impact

Chakrabarti, who graduated with a Ph.D. in urban planning and development in 2015, collected and analyzed all of the transit data for the paper. He has since returned to India, where he works as an assistant professor at the Indian Institute of Management Ahmedabad.

Rhoads, who finished her Ph.D. in urban planning and development in 2014, is currently a senior research associate with the South Bay Cities Council of Governments, where she’s been working for the past three years on developing innovative methodologies for suburban transportation strategies to measure greenhouse gas emissions.

“Almost every day, I see in my work how valuable a dataset like the ADMS is to transportation,” Rhoads said. “This dataset is so important to be able to evaluate the before and after effects of transportation projects and therefore asses their effectiveness. This is something that is not done enough because the data [are] lacking.”

This is the second time in three years that USC Price faculty have taken home the award. In 2015, Tridib Banerjee and Deepak Bahl received the honor for their paper, “Walking to School: The Experience of Children in Inner City Los Angeles and Implications for Policy.”