Researchers at the organization studied and mapped development patterns around 284 stations on the Massachusetts Bay Transportation Authority’s rapid transit and commuter rail lines and found that more than 517,000 houses and apartments are within a half-mile of a station. About 253,000 more could be added if land around all of the transit system’s stations averaged 10 housing units per acre, instead of the current 6.4.

That’s the upshot of new data being released this week by the Massachusetts Housing Partnership, a nonprofit that advocates for affordable housing.


“It’s just a thought experiment,” said Tom Hopper, the group’s director of research and analytics. “But it shows us that there’s a lot of potential in the system, not just to increase our housing supply but to do it in the right way, in the right places.”

Ten units per acre is about the density of the neighborhood around Forest Hills Station at the end of the Orange Line, Wonderland Station on the Blue Line in Revere, and Savin Hill Station on the Red Line in Dorchester.

That’s far less than in the most densely populated areas around T stations: Symphony and Boylston on the Green Line and Charles/MGH on the Red all top 50 units per acre. But 10 units per acre is far more than in the sparsest areas, in outer-suburban towns like Kingston, Grafton and Littleton, where stations are ringed by parking lots and open space.

Hopper was quick to note that large-scale or even medium-scale development may not be appropriate at every commuter rail stop. But many places could handle more housing, he said. “There’s certainly some low-hanging fruit across the system,” he said. “We might focus on those areas.”

In recent years, developers have rushed to build near MBTA stations — particularly on the main rapid-transit lines. Sixty percent of the $9.6 billion worth of construction underway in Greater Boston is within a five-minute walk of one, according to a report by the commercial real estate firm Perry.


Development is straining the already-crowded MBTA system, but it is also adding more customers who will demand — and help pay for — better and more frequent transit service, the study’s authors noted.

And lately, state officials have been leaning on developers who build near the T to help pay for improving stations and operations.

The Baker administration has been trying to put more MBTA-owned land near stations into the hands of developers, signing deals like the one for a roughly 600-unit apartment building at Quincy Center Station on the Red Line and for a 67-unit building that opened last year near the Beverly Depot commuter rail station.

That building was leased quickly to tenants who wanted to live in a walkable suburban neighborhood, said Sarah Barnat, whose Barnat Development built the complex, called Holmes Beverly. With a 31-minute ride to North Station, it was appealing to couples if one person worked downtown and the other on the North Shore.

“You can live an almost-car-free existence in a suburban atmosphere,” she said. “Which a lot of people are happy to do.”

Barnat noted that Beverly had rezoned the area around the train station for larger-scale development. In many towns, though, that is not the case.


Housing advocates and some politicians on Beacon Hill have pushed in recent years for legislation that would encourage, or even require, some multifamily zoning within a half-mile of MBTA stations.

But nothing has been passed. This legislative session, a measure to promote such multifamily zoning has been waylaid by the Legislature’s Housing Committee since May, while Governor Charlie Baker is pushing a different bill that would make it easier for cities and towns to rezone, while stopping short of any transit-oriented mandates.

Hopper said the Massachusetts Housing Partnership isn’t advocating for any particular bill. Rather, it’s trying to point out that opportunities exist around train stations, he said. The group is launching a website to map each station and highlight the housing density around it. Hopper said the group hopes to start a conversation focused on how housing and transportation are inextricably linked, and how building near transit lines won’t just add housing: That could also take cars off the region’s crowded roads.

“That’s really kind of where we’re coming from,” Hopper said. “It ticks boxes on the housing crisis, the transportation crisis, the climate crisis. It makes sense that people are trying to tie this all together.”

Tim Logan can be reached at tim.logan@globe.com. Follow him on Twitter at @bytimlogan.