Zoning Maps as Budgets

In 2018, the planning department released a study of Demolitions and replacement homes. Page 4 contains a bar chart showing the relative sizes of Arlington’s zoning districts:

Total Acres of Land By Zone

The folks in Arlington’s Department of Planning and Community Development were kind enough to provide me with a copy of the underlying numeric data. I’ll present that shortly, but for the moment, I’d like to make a proposition about zoning maps: that they are budgets given in acres rather than dollars. A zoning map takes a finite pool of resources (land) and allocates it among specific set of concerns (land uses).

Here’s the size of each district, along with the percentage of land that it accounts for.

ZoneDistrict NameAcres%total
B1Neighborhood Office 25.89 0.79%
B2Neighborhood Business 16.92 0.52%
B2AMajor Business 22.48 0.68%
B3Village Business 28.43 0.87%
B4Vehicular Oriented Business 29.91 0.91%
B5Central Business 10.48 0.32%
IIndustrial 48.96 1.49%
MUMulti-use 18.26 0.56%
OSOpen Space 270.99 8.25%
PUDPlanned Unit Development 16.16 0.49%
R0Large Lot Single-Family 237.85 7.24%
R1Single-family 1,777.64 54.14%
R2Two-family 619.66 18.87%
R3Three-family 8.25 0.25%
R4Townhouse 19.49 0.59%
R5Low-density Apartment 63.76 1.94%
R6Medium-density Apartment 49.10 1.50%
R7High-density apartment 18.65 0.57%
TTransportation 0.76 0.02%
TOTAL3283.65100.00%

I’m going to roll these up into four categories

  • Residential (the “R” districts)
  • Commercial (the “B” and “I” districts)
  • Open space (the “OS” district)
  • Other (the MU, PUD, and T districts)
UseAcres% total
Commercial183.085.58%
Residential2794.4085.10%
Open Space270.998.25%
Other35.181.07%
Total3283.65100.00%

I’d like to point out several things about this summary.

First, 85% of Arlington’s land is residential and 61% is exclusively set aside for single-family homes. When our zoning laws were re-written in the mid-1970’s two substantial goals were (1) limiting the potential for population growth, and (2) making Arlington a “traditional family town” (which I interpret to mean “a place for families with children”). The preference for single-family homes has arguably made those goals easier to achieve; single-family homes mean fewer homes per lot, and they offer enough floor space and bedrooms for families with children. I think we’ve met those objectives. Arlington’s population dropped from 54,000 in 1970 to around 45,000 today, we have well-respected public schools, and our single-family homes have a lot of utility for growing families. We’re a great town for raising kids. Our residential taxes are can be high, but I’d argue this is a design feature rather than a defect.

Second, 8.25% of our land is “Open Space”, aka “parcels under the jurisdiction of the Park and Recreation Commission, Conservation Commission, Arlington Redevelopment Board, Massachusetts Department of Conservation and Recreation, or Massachusetts Bay Transportation Authority (MBTA)”. It’s public land, and it’s a great asset. For better or worse, our Opens Space districts generate no tax revenue.

Third, 5.6% of the town’s land is zoned for commercial use. This is the set of land and buildings that can make up Arlington’s commercial tax base. When I moved to town in 2007, our commercial tax base was 5.4%; that figure increased for a few years (after the 2008 recession), eventually settling back down to 5.4% in 2019. With 5.6% of land zoned commercially, a 5.4% commercial tax base doesn’t strike me as unreasonable. I suspect the goal was to have enough businesses to provide local amenities, but without turning the town into a commercial center.

Finally, the “Other” category can be divided up three ways:

  1. The Multi-Use district is the former site of the Symmes hospital. It used to be known as the Hospital District, and is currently home to Arlington 360, a large apartment complex.
  2. The Planned Unit development district is also know as the Mugar Property. In the early 1980’s, David Mugar tried to develop it as office and retail space. Today, Oaktree Development is petitioning to develop the site as apartments and townhouses.
  3. Finally, the Transportation district is “bus terminals, open space, and the Minuteman Bikeway”; it’s a very small portion of the town’s land.

So that’s our land budget: 85% residential, 8.25% public open space, 5.6% commercial, and 1% other. This is a preference for how the land is used, and a preference for how the local government is funded (Arlington’s main source of income is property taxes).

A common budgeting exercise is to take an existing breakdown and ask “what if we allocated things differently”? For the sake of discussion, let’s say we wanted 50% of the town to be Open Space (i.e., publicly-owned and publicly-accessible green space). This might be driven by a desire for more trees and wooded areas, better stormwater management, climate resilience, heat island reduction, and so on. The conceptual change is easy: take half the town, pick it up, and set it down on the other half. Done [1].

Stacking half the town on top of the other means we’d have enough room to fit all of the homes and businesses that we currently have. The buildings would be taller, there’d likely be far fewer single-family homes, and there’d be a ton of green space. As with any budget, there’s a tradeoff.

Or suppose we wanted to increase the town’s commercial tax base. This topic surfaces from time to time, particularly when the first set of property tax bills goes out during a fiscal year. Commercial property taxes are assessed in much the same way as residential: the assessments are based on the value of land and buildings; dollars and square feet [2]. One can increase dollars (i.e., when a commercial property is sold above its assessed value), one can increase square feet (by allowing larger buildings, or allowing some non-commercial land to take on commercial uses), or one can try to find a way to reduce the total assessed value of residential properties. If none of those choices are appealing, then you probably won’t get a higher commercial tax base. Again, budget tradeoffs.

In conclusion, my goal has been to get people thinking about Zoning Maps as a form of budget. Arlington’s capital and operating budgets have changed over time, as has our zoning map. I’d like us to think of what we might do differently in the future.

[1] In reality, the implementaton details would probably be hideously complex; but the concept is simple.

[2] There’s also a “Personal” component to commercial taxes, which involves equipment and supplies used in conducting a business. This is mere sliver of Arlington’s total tax revnue.

Redlining and Urban Heat Islands

In the 1930’s the Home Owner’s Loan Corporation of America (HOLC) created actuarial maps of the United states. These maps were color coded — Green, Blue, Yellow, and Red — to reflect the amount of “risk” associated with home loans in those areas. The colors corresponded to “Best” (green), “Still Desirable” (blue), “Definitely Declining” (yellow), and “Hazardous” (red). Being in a green area made you likely to secure a federally-insured home mortgage, something that was effectively unavailable to red areas. Red areas were often associated with black populations, and these maps are where the term “redlining” comes from.

Here’s an HOLC map of Arlington, courtesy of the University of Richmond’s mapping inequality project.

"Redline" map of Arlington, MA, courtesty of the Home Owner's Loan Corporation
HOLC “redline” map of Arlington, Massachusetts

Note that Arlington does not have any “Hazardous” (red) areas; 68% of the town fell into the top two grades, meaning that we were generally a safe bet as far as federal mortgage insurers were concerned. To the extent that the HOLC preferred white communities, Arlington seems to have fit the bill. According to US census data.

  • 1930: population 36,094. No breakdown by race.
  • 1940: population 40,013. 99.8% white.
  • 1950: population 44,353. No breakdown by race.
  • 1960: population 49,953. 99.7% white.
  • 1970: population 53,524. 99.0% white.
  • 1980: population 48,219. 97.3% white.

Today, Arlington is about 84% white. But during the time that mortgage approvals were based on the HOLC maps — the mid 1930’s through the mid 1960’s — we certainly qualified as an overwhelmingly (> 99%) white community.

Arlington had four yellow-lined (“definitely declining”) areas; about 32% of the town. C1 (on the western edge of town) was noted for an “infiltration of Jews”, a “heavy concentration of relief families”, and hilly terrain which was “not conducive to good development”. But it had good schools and a nice area along Appleton St. C2 (along Mass Ave and Mill Brook) was noted for “obsolescence” with “business and housing mixed together” and “railroad tracks through [the] neighborhood”. There was an infiltration of lower-class people, a moderate number of relief families, and “little possibility of conversion of properties to business use”.

C3 (East Arlington, around the present location Thompson School and Menotomy Manor) was noted for “Obsolescence, poor reputations” and “foreign concentration”. There was an “infiltration of foreign [residents]” and a “heavy concentration of relief families”. On the positive side, there were “a few small farms in this section of high grade development of the ground [which] may be anticipated in the early future with modest houses”.

Finally, C4 (around Spy Pond, and near the Alewife T station) was “obsolescent”, with an infiltration of foreign families, and a moderately heavy concentration of relief families. The HOLC noted that “Houses East of Varnum Street [and] south of Herbert Road are built on low ground and many have damp basements which makes them difficult to keep occupied”.

That’s what the HOLC saw as the declining side of Arlington: Jews, foreigners (mostly Italian), relief families, obsolescence, damp basements, and proximity to the Boston-Maine railroad.

Exercise for the reader. Arlington has five public housing projects: Drake Village, Winslow Towers, Chestnut Manor, Cusack Terrace, and Menotomy Manor. What HOLC colors are associated with our public housing?

Buildings last for decades, and effects of the HOLC’s underwriting policies are still with us today — sometimes in unexpected ways. A 2020 paper called “The Effects of Historical Housing Policies on Resident Exposure to Intra-Urban Heat: A Study of 108 US Urban Areas” examined 108 communities, and tried to determine if there was a relationship between redlined areas and urban heat islands. Nationwide, this is what they found:

Land surface temperature as a function of HOLC risk category
Land Surface Temperature, by HOLC risk rating

LST stands for “land surface temperature” and shows how different HOLC risk categories compare to the overall temperature of a region. Green areas tend to be cooler, with less paved surface, more extensive tree canopies, and buildings with reflective exteriors. Red areas are warmer with more paved surfaces, less tree canopy, and building exteriors that absorb and release heat (e.g., brick and cinderblocks). While the degree varies across different parts of the country, the general trend is the same: as one goes from green to red, the surface temperature goes up. Formerly-redlined areas are far more likely to contain heat islands.

Exercise for the reader. Are there heat islands in Arlington? What (HOLC) color are they?

As the global temperature warms, Arlington (like many other communities) will have to contend with heat islands. The treatment is likely to be area-specific, following patterns laid out in the HOLC’s maps from the early-20th century.

The Color of Law on Sunnyside Ave

I live on Sunnyside Avenue in Arlington, Massachusetts. The neighborhood was built as two subdivisions in 1948, with 42 duplexes (84 homes total). These were starter homes with 792 square feet of finished space plus a basement with a garage. I affectionately refer to them as excellent specimens of mid-century slap-up. They were constructed in the mid 20th century, and the builder just kind of slapped them up.

Here’s one of the original newspaper ads for these homes.

Sunnyide - a Community of Duplexes in Arlington! Priced from $8750!

It’s fun to read the ad copy. The homes are “within walking distance of schools, transportation (MTA) and shopping centers” (a selling point that endures to this day); the lots are “large to provide for individual landscaping” (they’re 3,000 square feet give or take, which is unbuildably small by today’s zoning laws); and the homes have “full-sized dining rooms”, “spacious streamlined kitchens”, and “two large sunny bedrooms” (so much largeness for 792 square feet). I guess this was a time when good salesmanship took precedence over truth in advertising. It was a different time.

I have to admit, they were a pretty good deal. $8750 in 1948 is equivalent to around $95,000 in 2020 dollars; these homes, with the original floor plan, currently sell for around half a million dollars.

However, the part of the ad that most caught my attention was “All Mortgages FHA 25 years”. FHA refers to the Federal Housing Administration, who were the primary mortgage underwriters during the middle of the 20th century. They’re also an example of how the United States used housing policy as a tool for segregation; the FHA was in the business of insuring mortgages for white families in white neighborhoods. The Fair Housing Center of Greater Boston has a short summary of FHA practices. There’s also discussion of the FHA in Segregated by Design.

Which is to say, my nice little neighborhood in East Arlington was likely designed, built, and sold as a segregated development for whites.

Arlington’s biggest period of residential construction was in the 1920’s when we were building an average of 500 homes/year. But there was still a good deal of single- and two-family construction that took place from the 1930’s to the 1960’s — a bit over 5,000 homes. Since the FHA was the primary mortgage underwriter during that period, I think it’s safe to say that my neighborhood was probably not the only for-whites-only neighborhood in town.

I will end with two questions. How do we feel about this bit of history, and what (if anything) should we do about it?

Myths & Facts About Affordable Housing & Density

This timely report on the question of affordable housing vs. density comes from the California Dept. of Housing & Community Development and mirrors the situation in the region surrounding Arlington MA.

Housing production has not kept up with job and household growth.   The location and type of new housing does not meet the needs of many new house- holds. As a result, only one in five households can afford a typical home, overcrowding doubled in the 1990’s, and too many households pay more than they can afford for their housing.

Myth #1
High-density housing is affordable housing; affordable
housing is high-density housing.
Fact #1
Not all high density housing is affordable to low-income families.

Myth #2
High-density and affordable housing will cause too much traffic.
Fact #2
People who live in affordable housing own fewer cars and
drive less.

Myth #3
High-density development strains public services and
infrastructure.
Fact #3
Compact development offers greater efficiency in use of
public services and infrastructure.

Myth #4
People who live in high-density and affordable housing
won’t fit into my neighborhood.
Fact #4
People who need affordable housing already live and work
in your community.

Myth #5
Affordable housing reduces property values.
Fact #5
No study in California has ever shown that affordable
housing developments reduce property values.

Myth #6
Residents of affordable housing move too often to be stable
community members.
Fact #6
When rents are guaranteed to remain stable, tenants
move less often.

Myth #7
High-density and affordable housing undermine community
character.
Fact #7
New affordable and high-density housing can always be
designed to fit into existing communities.

Myth #8
High-density and affordable housing increase crime.
Fact #8
The design and use of public spaces has a far more
significant affect on crime than density or income levels.

See an example of a “case study” of two affordable housing developments in Irvine CA, San Marcos at 64 units per acre.

Affordable housing: San Marcos Apartments, Irvine CA, 64 units/ acre

San Paulo at 25 units per acre.

Affordable housing at San Paulo apartments, Irvine CA, 25 units/ acre.

Both are designed to blend with nearby homes.

The Gentrification of Arlington

(Comments presented to the Arlington Redevelopment Board and Select Board during a public hearing on Jan 13, 2020)

Steve Revilak, 111 Sunnyside Ave. In the interest of disclosure, I live in market rate housing that was built by a developer. Among Arlington residents, I’m not unusual in that regard.

At the end of December, a friend sent me an article that appeared on Redfin’s blog, which ranked the most competitive real estate markets in 2019. Out of 20 listings, three were neighborhoods in Arlington: East Arlington at #3, the Brattle Street Area at #5, and Arlington Center at #12. This is only one data point, but Redfin is a national realtor and works in markets all across the country. Arlington is a desirable place to live.

Housing costs have steadily increased over the last 20 years, modulo a brief reset during the economic recession of 2008. For example, the prior owner of my house purchased it for $151,000 is 1999. I purchased it for $359,000 in 2007 (when it was assessed at $287k). Today, it’s assessed at $501k, which is consistent with similar home sales from 2018.

The net effect: each year a new family moves to town, they have to have a more money (or be willing to spend more on housing) than a family who moved in the year before. With that in mind, I’d like to cite a few figures from the 2019 Town Survey:

  • Question 37: Indicate the number of years lived in Arlington. 59% of respondents indicated 15 years or less. Nearly 30% indicated five years or less. Despite the prices, people still move here.
  • Question 40: What was your annual household income in 2018. The most common response was “more than $200,000”, with over 28% answering that way. Nearly 71% of respondents indicated earning $100,000/year or more. Arlington’s median income is likely higher than HUD’s AMI for the Metro Boston area.
  • Question 41: What is the highest level of educated completed by a member of your household. Over 73% indicated having a masters degree or higher.

I don’t mean to knock people who’ve lived here 15 or fewer years, have advanced degrees, or have household earnings of $200,000 or more per year. I check every single one of those boxes myself. But I do want to point out that we are a highly educated and affluent community. Put another way, we have a population that matches the cost of our housing.

Twenty years of gentrification haven’t killed us: we’ve expanded town staff and services, we’re renovating public buildings, and we’re getting a new high school. Those are all good things, made possible because residents have the money to pay for them, and have been willing to do so.

We can absolutely keep the status quo we’ve had, but I want to recognize that the combination of the housing market and Arlington’s policies have created an economic barrier to living here. I see two issues: one is affordability, and the other is an imbalance between supply and demand.

There are a variety of things we could do, and I think we should consider all of them. I don’t see a viable way to relieve housing pressure that doesn’t involve more housing. And that’s what I hope we can do over the coming years: find ways to build more housing.

Improving Residential Inclusiveness, Sustainability, and Affordability by Ending Single-Family Zoning

(Contributed by Ben Rudick and Steve Revilak)

We should end exclusionary Single Family Zoning in Arlington. This is inspired by Minneapolis which ended Single Family Zoning city-wide last year, as Oregon did. To be clear, we’re not suggesting an end to single family homes, only to exclusionary Single Family Zoning; you can still have a single-family house, but now you’d have the option to build a two-family or duplex instead.

79% of all residential land in Arlington is zoned exclusively for single family homes (in the R0 and R1 districts), meaning the only legal use of that land is for a single home built upon a large lot (source: Arlington GIS via the Department of Planning and Community Development). This is a problem for three key reasons:

  1. Single Family Zoning has a deeply racist past. It came into being after a 1917 Supreme Court ruling made it illegal to have “Whites only” neighborhoods. Instead, towns and cities, as encouraged by the federal government, enacted zoning that used economics instead of explicit racism to segregate neighborhoods. A popular strategy was to require large lots on which only expensive, individual homes could be built. Here’s an excellent short video on the topic: https://www.segregatedbydesign.com/
  2. It’s terrible for the environment. Living in a Single Family Home is akin to driving alone instead of carpooling or taking the bus: it’s the most carbon-intensive way to put a roof over your head. The more people you can house in the same structure, the less energy you spend per person. By spreading people out, we’re increasing the amount we drive and the carbon we emit. And we’re contributing to traffic congestion too.
  3. Arlington is becoming increasingly unaffordable. We have a massive (and growing) housing shortage; combined with continued job growth in the Greater Boston area, housing has gotten dramatically more expensive over the last 20 years. The only way for us to keep rising home prices in check is to significantly increase supply, which will be extremely difficult to do while keeping so much of our land reserved for single family homes.

If you’d like to support us, please share this post and join our Facebook group, Arlington Neighbors for More Neighbors, where we’ll post updates and hearing times for the warrant article we’ve submitted to effect this change.

Consider the Schools: Add More Housing

Jennifer Susse authored this letter on January 20, 2020. Ms. Susse is a member of the Arlington School Committee and a Town Meeting Member. She closely follows the costs and demographic trends of school enrollment and of Town finances.

I write in support of efforts to increase housing in Arlington, both as a resident and as a member of the School Committee. I support these efforts not in spite of their potential effects on our schools, but because of their potential effects on both schools and town.

I have often spoken to the community about our rapid enrollment growth — over 2,000 students added in the last 25 years, 60 percent of those in the last 10 years. Because of these large enrollment increases the Arlington Public Schools have had to add capacity, which the town has generously supported. So how can I be in favor of adding more housing to Arlington, and thus potentially adding even more students to our already stressed school facilities?

Losing diversity
I will get to the capacity issue in a bit, but first I want to point out that in the last 30 years Arlington has lost both economic and generational diversity. The story about the loss of economic diversity is well known; the loss of generational diversity less so.

Between 1990 and 2010, the percentage of residents between 20 and 34 dropped from 28 percent to 17 percent. During that same period, the population over 65 dropped from 18 percent to 16 percent. What replaced these demographic groups were primarily residents between the ages of 35 and 54 and 0 and 14. In other words, mostly families with school-aged children. The loss of both types of diversity weakens the fabric of our community. However, the loss of generational diversity also weakens the town’s finances.

The average cost to the town of an additional student is about $8,500, a number that includes what’s known as the Enrollment Growth Factor (the amount that the town gives to the schools for each additional student in the system, currently at 50 percent of the per pupil cost of the preceding year, or $7,297), as well as the average cost of the benefits that the town pays for new hires.

What this means is that during the time a household has children in the school system, it is likely receiving more in benefits than it pays in taxes. For the town’s finances to work, we also need people who do not have children to live and pay taxes in Arlington, including young adults and older adults for whom Arlington is becoming less affordable because of condo conversions, teardowns, etc.

Overcrowded classrooms
But what about our overcrowded classrooms? The answer is that given the type of housing likely to be created on the main corridors, and the timing of that housing construction, I am not worried about further stresses to our school facilities.

By the time new housing is built, our elementary-aged population will likely be in modest decline. Five to 10 years out we expect to see enrollment stabilize at the middle and high school levels as well. That does not mean that we will have tons of extra space; just that we will no longer be in danger of taking over art, music, and literacy rooms for general classroom use.

Enrollment projections made by Dr. Jerome McKibbin in 2015 have so far been fairly accurate. His revised projections show that, without additional housing, we are expected to have 350 fewer elementary-aged students in the Arlington Public Schools 12 years from now than we have today.

The discussion about housing in Arlington reminds me of the discussion a few years ago over the Affordable Care Act. At that time, there was a lot of anxiety about potential changes to the health-care system, but insufficient appreciation (in my opinion) of the then current trends.

Zoning changes
Any discussion of zoning changes in Arlington must take an honest look at where we are now, and the direction we are headed in if there were no zoning changes. Our current trends have us losing natural affordability and economic and demographic diversity because of teardowns, condo conversions and sharp price increases. We don’t have the option to freeze Arlington as we know it today (or 10 years ago) in place.

In closing, I would like to say that I am proud of our excellent schools and strongly believe that families who have recently moved to Arlington have strengthened our community, but I do not want Arlington to become a place where people move in with toddlers and move out soon as their children graduate from high school. The current trends have us losing both economic and generational diversity, which threatens not only our community and civic life, but our financial health as well. Adding more and diverse housing can help.

“Surging Seas” Risk Zone Map Shows Arlington Wetlands Threat

Climate Central’s Surging Seas global Risk Zone Map provides the ability to explore inundation ​risk ​up to 30 meters across the world’s coastlines as well as local sea level rise projections at over 1,000 tide gauges on 6 continents.

Set the map for Boston MA and focus in on the Arlington area to see how the town would be affected by rising sea levels, as predicted over the next few decades.

Map areas below the selected water level are displayed as satellite imagery shaded in blue indicating vulnerability to flooding from combined sea level rise, storm surge, and tides, or to permanent submergence by long-term sea level rise. Map areas above the selected water level are shown in map style using white and pale grays. The map is searchable by city, state, postal code, and other location names. The map is embeddable, and users can customize and download map screenshots using the camera icon in the top right of the screen.

For map areas in the U.S., the Risk Zone map incorporates the latest, high-resolution, high-accuracy lidar elevation data supplied by NOAA, displays points of interest, and contains layers displaying social vulnerability and population density. For map areas outside the U.S. the map utilizes elevation data from NASA’s Shuttle Radar Topography Mission (SRTM).

Arlington wetlands on interactive map set to show future 8 foot water rise.

https://ss2.climatecentral.org/?#13/42.4074/-71.1100?show=satellite&projections=0-K14_RCP85-SLR&level=8&unit=feet&pois=hide

Arlington Can’t Wait for Affordable Housing to Just Naturally Occur

This letter appeared in the Boston Globe on Dec. 19th. It’s reprinted
here with permission from the author, Eugene Benson.

The Dec. 12 letter from Jo Anne Preston unfortunately repeats misinformation making the rounds in Arlington (“Arlington is a case study in grappling with rezoning“).

At April Town Meeting, the Arlington Redevelopment Board recommended a vote of no action on its warrant article that would have allowed increased density along the town’s commercial corridors in exchange for building more affordable housing (known as “incentive zoning”), when it became obvious that the article would be unlikely to gain a two-thirds vote for passage, in part because of the complexity of what was proposed.

A warrant article to allow accessory dwelling units in existing housing (“in-law apartments”) gained more than 60 percent of the vote at Town Meeting but not the two-thirds vote necessary to change zoning.

The letter writer mentioned “naturally occurring affordable apartment buildings.” The typical monthly rent for an apartment in those older buildings ranges from about $1,700 for a one-bedroom to about $2,300 for a two-bedroom, according to real estate data from CoStar. Those are not affordable rents for lower-income people. For example, a senior couple with the national average Social Security income of about $2,500 per month would spend most of their income just to pay the rent.

We need to protect the ability of people with lower incomes to withstand rent increases and gentrification. That, however, requires a different approach than hoping for naturally occurring affordable housing to be there even five years from now.

Eugene B. Benson

Arlington

The writer’s views expressed here are his own, and are not offered on behalf of the Arlington Redevelopment Board, of which he is a member.

Transit Corridor Strategy for More Housing

from Karen Kelleher, Reporter

Interested in new policy developments on housing production in the Greater Boston area? The latest research from Mass Housing Partnership (MHP) is of interest.  They just released (Dec. 18, 2019) in interactive map showing relative housing density around every mass transit and commuter rail station in the system, concluding that the region could add 235,000 units if every community allowed density as of right in the area around transit.

CHAPA has legislation pending that would require municipalities served by transit to allow higher density as of right within a certain distance from transit stations. You’ll see that the density around Alewife is not too bad in the context of the entire system.

This is mostly because of very high density in Cambridge near Alewife, but the density of two and three families in East Arlington shows better housing density than the sea of single family zoning around many commuter rail stops.  
You can check it out here:https://www.mhp.net/news/2019/todex-research-brief