Langley Park residents are the focus of a new study examining whether the coming Purple Line will make residents who live near stations more physically active. (File photo by Marvin Joseph/The Washington Post)

As construction on Maryland’s Purple Line gets underway, a University of Maryland researcher is starting to examine whether the light-rail line will make people healthier, or at least more physically active.

Jennifer Roberts, an assistant professor in the Department of Kinesiology, said previous studies have found that people who live near public transportation are generally more physically active because they often walk or bike to and from the transit stop, as well as to shop and make other trips.

But most of those studies, including in Seattle and San Diego, looked at majority-white populations, she said. Roberts said she’ll focus on the Langley Park area of Prince George’s County because it’s mostly  African American and Latino and has a broad range of ethnicity, incomes and education levels.

“It’ll be more diverse in terms of the participation,” Roberts said. “It’s the perfect kind of sample for epidemiology.”

Moreover, Roberts said, Prince George’s has one of the highest obesity rates in Maryland, and Latina and African American women have the highest obesity rates nationwide. So being able to walk to a light-rail station, she said, should benefit them in particular.

Roberts said she’s starting to conduct focus groups and send out questionnaires to find out how physically active about 11,000 residents are before the Purple Line is built. Some of the participants also will wear activity monitors and GPS trackers for seven days. Then she plans to look at how active they are one year after the light-rail line opens, three years after, and five years after.

The 16-mile Purple Line, which is being built in an arc inside the Capital Beltway between Bethesda in Montgomery County and New Carrollton in Prince George’s, is scheduled to begin carrying passengers in 2022.

Roberts said she’s also interested in how the Purple Line will affect Langley Park residents’ mental health, particularly how much stress they feel wondering if they’ll be priced out as areas around light-rail stations redevelop, driving up rents and home prices.

“Gentrification is a really big issue,” Roberts said. “We’ve seen it with other light-rail lines. If we look at it, maybe we can prevent it.”

The University of Maryland is funding the initial research with a $50,000 grant, she said. She said she plans to seek more funding, hopefully to try to determine if a new light-rail line affects nearby residents’ body mass index, blood pressure, and other health measures.

The Purple Line, she said, will bring “a melting pot of issues” that ask a larger question: “Is it going to improve people’s health in certain ways or make it worse?”