Person waiting by metro train

Photo by Porapak Apichodilok

November 15, 2017

As communities in an east-west stripe across Prince George’s and Montgomery Counties prepare to break ground on the Washington Metropolitan Area Transit Authority’s long-awaited Purple Line, Assistant Professor Jennifer Roberts (Kinesiology) wants to know how the new light rail might affect the health of people who live near it.

“Research has shown, when people live near public transportation they are more physically active,” Dr. Roberts said. This is because they walk from their homes to the public transportation stop and to nearby shopping and attractions as well. 

Using UMD Tier 1 grant funding, Dr. Roberts will send surveys to 11,000 adults in a study area in Langley Park, near the future Langley Park Purple Line stop. She will target households within a half-mile of the stop, and also a control group from one-half to three miles away from the stop. 

Dr. Roberts will ask survey respondents about their public transit use and the types of active transportation they use: do they walk, bike or drive to the stop? She will survey adults and, where permission is granted, their children about their attitudes towards public transportation.

A subset of the survey respondents will wear an activity monitor and GPS logger, keep a travel diary, and participate in focus group discussions. 

The study will leverage on the collaborative expertise of Dr. Brit Saksvig (Epidemiology) and Prof. Ming Hu (Architecture), and will happen in two waves: from November 2017 through January 2018, and from April through June 2018, to capture seasonal differences. 

Prince George’s County is among the Maryland counties with the highest rates of overweight and obesity, with 33% of adults having a BMI of 30 or above (according to In addition, Latina and African American women have the highest rates of obesity nationwide. Langley Park is an ethnically diverse area, with a large minority and Spanish-speaking population. “The Purple Line development would be perfect for people in this demographic in terms of health benefits,” Roberts said.

Dr. Roberts worries that the people living in Langley Park now may be pushed out when the Purple Line gets built. “When you have a new transit system coming in, particularly light rail, transportation equals gentrification,” she said. “A lot of people won’t want to leave there, but if the rent goes up, if prices go up, then they will get priced out. It’s a petri dish in terms of gentrification.” 

Dr. Roberts plans to pursue further research funding to do a follow-up study in the same area, after the Purple Line has been built. The metro system in Washington, D.C. is the third largest in the United States. She points out that the Purple Line is the first east-west line on the system, connecting suburbs to the north of D.C. without traveling through the center city. She also notes that the use of light rail on parts of the line will create a much closer connection to the streetscape than a heavy track would, making public transportation that much more accessible in the neighborhoods.

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Jennifer D. Roberts