Montgomery County Executive Isiah Leggett, left, Prince George’s County Executive Rushern L. Baker III, center, and University of Maryland President Wallace Loh are among the signers of an agreement on Nov. 28 to preserve affordable housing, create jobs and protect businesses along the 16-mile Purple Line corridor. (Katherine Shaver/The Washington Post)

Government, business and community leaders from Montgomery and Prince George’s counties agreed Tuesday to preserve affordable housing and create jobs along the Purple Line corridor where construction is expected to drive up land values around its 21 stations.

The agreement, thought to be the second of its kind in the country, isn’t legally binding. But signatories called it a public commitment to help those who live and work in the 16-mile light-rail corridor stay and benefit from the state’s $5.6 billion transit investment.

“There are billions of dollars that will be invested to build this shiny new transit system, and that’s good . . .The question is, who’s going to be along the corridor in five years, 10 years, 15 years when it’s built?” said David Bowers of the nonprofit group Enterprise Community Partners.

Without governments, foundations and developers working to maintain affordable housing, Bowers said, residents will be displaced.

“We know it’s happening,” Bowers said. “You can go 15 minutes down the road to the nation’s capital and go neighborhood by neighborhood.”

Prince George’s County Executive Rushern L. Baker III (D) said he has heard from residents, particularly in the heavily Latino Langley Park area, who welcome the Purple Line but are concerned about being priced out.

“This agreement says, ‘We hear you,’ ” Baker said. “We’re looking at ways . . . to give them every opportunity they want to stay there.”

Purple Line supporters have long touted the light-rail project, which started construction in August, as a way to rejuvenate aging suburbs between Bethesda and New Carrollton, in addition to providing faster, more reliable public transportation. It was no coincidence that the signing occurred before nearly 200 people amid the scent of new carpet at The Hotel at the University of Maryland, upscale lodgings that opened two months ago on Route 1 in College Park, near the site of a future Purple Line station.

But even Purple Line supporters say they are well aware that the new hotels, restaurants, shops and homes that the Purple Line will attract could push aside lower-income residents who most need it to reach jobs and schools.

Officials said it took three years to work out the agreement reached by members of the Purple Line Corridor Coalition, a group formed by the University of Maryland’s National Center For Smart Growth. It includes community officials, nonprofit groups and businesses along the route.

Gerrit Knaap, executive director of the National Center for Smart Growth, said the discussions grew out of concerns voiced by CASA, an immigrant rights organization in Langley Park.

Knaap said the coalition modeled the pact on one in the Seattle area.

“You can feel the energy here,” Knaap said after the signing. “People are here with the right frame of mind and the tools to really pull this off.”

The agreement doesn’t prescribe how the suburbs will accomplish the four goals: supporting and growing local businesses, creating jobs, maintaining lower-income and workforce housing, and supporting “vibrant, sustainable” communities.

All of them, Knaap said, will require cooperation among governments, the private sector, nonprofit organizations and community groups.

Montgomery County Executive Isiah Leggett (D) said he wished the county had had a similar commitment in place to protect small businesses as downtown Silver Spring was redeveloped.

With the Purple Line coming, Leggett said, “We’re trying to get out in front of those bumps and challenges.”

The Purple Line, which is estimated to cost $2.4 billion to build, is scheduled to open in 2022. It is being built as part of a 36-year public-private partnership valued at $5.6 billion. A lawsuit opposing the project’s ridership projections is pending before the U.S. Court of Appeals for the D.C. Circuit.

Knaap said the smart-growth center will continue to analyze rents, home sales, wages, unemployment and other economic indicators annually as the Purple Line is built and after it opens.

“Our goals is to hold us all accountable,” Knaap said. “If it’s not moving in the right direction, we’ll change course.”