Accessory Dwelling Units: Policies, Attitudes in Boston Region

from Alexandra P. Levering , Thesis, Urban & Environmental Policy and Planning, Tufts University, August 2017

By 2017 65 out of 101 municipalities in the greater Boston (MAPC) region allowed Accessory Dwelling Units by right or by special permit. The average number of ADU’s added per year was about 3. But by 2017, Lexington had 75 ADUs, Newton had 73 and Ipswich had 66. It is a slow process for a variety of reasons, but the number of units grows over time.

AARP recommends ADU’s. The help homeonwers cover rising housing costs by providing income trhough rent. They also create a space for a caretaker or a family member to live close by, as the homeowner ages.

Autism Housing Pathways and Advocates for Autism of MA (AFAM) came together to advocate for an ADU bylaw to benefit parents of adult children with disabilities. For more information see her complete thesis (with a very useful set of tables and bibliography) HERE.

Accessory Dwelling Units (ADUs) provide multigenerational housing options for aging parents and for adult children. They help families manage changing lifestyle, fiscal and/or caretaking situations.

This type of housing is seen by many as a clear opportunity to offer more affordable residential opportunities. One reason why they are slow to develop is the cost of renovation and construction for homeowners. Some communities offer low or no interest loans to encourage more ADU development.

Transportation Emissions and MBTA Communities in Arlington

by Anson Stewart

Last year, the New York Times published The Climate Impact of Your Neighborhood, Mapped. This interactive feature shows that across the country, carbon emissions per household tend to be lower in relatively dense, walkable, and transit accessible areas. Compared to nearby communities like Winchester, Lexington, and Belmont, the average household in Arlington is responsible for much lower carbon dioxide-equivalent (CO₂e) emissions. Allowing more housing along Mass Ave and Broadway, as proposed by the town’s MBTA Communities Working Group, would enable more households to live in these lower-emissions neighborhoods and could be a meaningful step toward reducing driving and Massachusetts’ climate impact.

Zoning Artificially Limits Housing Supply

As noted in the NYT feature above, “For many people today, it is often easier and cheaper to find a home in a high-emissions community than a lower-emissions one… Many cities and local governments often artificially limit the amount of denser or transit-friendly housing available, particularly in wealthier neighborhoods, through zoning that favors single-family homes or requirements around minimum lot sizes and parking spaces.” Zoning restrictions from the 1970s severely constrain housing capacity along the corridors that help reduce climate impacts in Arlington. Those restrictions push families out to places where people drive more to meet their daily needs.

Driving (VMT) is the Largest Source of Massachusetts’ Climate Emissions

Cars are mind-bogglingly detrimental to our climate. According to the Massachusetts Clean Energy and Climate Plan for 2025 and 2030, “Transportation is the largest source of GHG emissions in the Commonwealth, responsible for 42% of statewide GHG emissions as of 2019… Emissions in the transportation sector have stagnated despite state and federal vehicle emissions standards that have gradually increased the fuel efficiency of vehicles. One major cause of increased emissions is the considerable increase in total statewide vehicle miles travelled (VMT) over the past 30 years.” Even as electric vehicles proliferate, the carbon intensity of our grid means driving will have a substantial climate impact, and reducing VMT must be a primary strategy.

The NYT analysis uses nationally available survey and expenditure data, so income and other effects may confound the estimates of transportation emissions. Massachusetts has a unique dataset that allows measuring driving emissions much more directly – the Massachusetts Vehicle Census (mentioned in the town Working Group report).

For each municipality, dividing the daily mileage driven (of cars registered there) by the population yields vehicle miles traveled (VMT) per capita, which varies widely in the Boston region. For example:

Cambridge: 8 miles per person per day
Somerville: 11
Arlington: 14
Boston: 14
Belmont: 14
Medford: 15
Lexington: 16
Winchester: 17
Waltham: 17
Woburn: 24

Thanks to Arlington’s walkable neighborhoods and transit access, our per capita VMT is lower than many nearby communities, and even on par with the City of Boston!

If Not Arlington, Then Where?

As a thought experiment, consider a climate-conscious family of four who wants to buy a condo in one of the communities above. If they can’t afford Cambridge, Somerville, or Arlington (where 2023 YTD median condo sale prices were $910k, $855k, and $810k respectively), they might consider Waltham or Woburn ($615k and $638k, respectively), or even Winchester or Lexington ($795k and $798k).

Lexington in particular might be appealing, especially as their Town Meeting recently adopted MBTA Communities zoning that allows much more multifamily housing than the minimum required (see the Lexington Cluster Housing Study Group materials in support of meaningful new housing supply). But even with that new capacity, the pace of development will be slow and most of the transportation “bones” of Lexington will be fixed. It is generally less transit accessible than Arlington, and all else equal, the family would likely end up driving more than if they lived in Arlington.

Assuming the average VMT per capita figures above, a family of four would end up driving an additional 2,920 miles per year living in Lexington versus Arlington. Assuming 30 mpg fuel efficiency and 8.9 kg CO₂e per gallon of gas, the incremental emissions from this one family would be 865 kg of CO₂e, equivalent to the annual carbon sequestered by six half-century-old red oak trees (according to Forest Service data here).

If this family moved to Woburn instead of Arlington, the incremental annual driving would be 14,600 miles. Associated emissions would be over 4.3 metric tons, equivalent to the annual carbon sequestered by 32 of those red oak trees.

Extrapolating These Emissions

How does this example of one family relate to the level of development Arlington might see from MBTA Communities zoning updates? The Working Group’s proposal had a nominal capacity of just over 7,000 housing units in an area that currently has about 2,100. The ARB recommendation to Town Meeting cuts the nominal capacity to around 3,400, for a possible net change of around 1,300 units theoretically allowed. Recent estimates (following the approach here) suggest that this capacity might result in 100 to 300 new housing units built in Arlington by 2033.

If new units enable 250 families like the one above to live in Arlington instead of Woburn, these back-of-the-envelope calculations suggest the avoided annual emissions from VMT reduction would be over 1,000 metric tons CO₂e in the year 2033.

Of course these are rough estimates, and the actual climate impact will depend on wider development trends, grid decarbonization, MBTA service, and the details of the zoning that Town Meeting adopts later this month. Low parking requirements (as originally proposed by the Working Group) and robust transportation demand management could help strengthen the climate change mitigation potential of Arlington’s MBTA Communities zoning update. On the other hand, further reductions in Arlington’s multifamily housing capacity would exacerbate emissions. Those concerned about reducing our collective climate impact should take note.

Emisssions MBTA Communities

Written by Guest Writer October 7, 2023

New Housing Offers Fiscal Benefits to Communities

Written by Guest Writer August 13, 2019

Housing

Does Building More Housing Reduce the Market Price?

Report by Vicki Been, Ingrid Gould Ellen, and Katherine O’Regan, Supply Skepticism: Housing Supply and Affordability, NYU Furman Center 8/20/18

Some affordable housing advocates question the premise that increasing the supply of market-rate housing will result in more affordable housing. This paper addresses the key arguments these “supply skeptics” make. Considering both theory and empirical evidence, the authors conclude that adding new market-rate homes moderates price increases does make housing more affordable to low- and moderate-income families.

At the outset, the authors review the relevant studies and conclude that “the preponderance of the evidence shows that restricting supply increases housing prices and that adding supply would help to make housing more affordable.” They then turn to several arguments the supply skeptics make. One key issue is whether adding housing in a part of the housing market will affect prices in another. The housing market is not uniform but composed of various submarkets. These submarkets relate to each other in complex ways. Critically, however, if demand forces up prices in a higher-end submarket, some buyers will turn to the next segment down and bid up prices there, generating a cascade. Adding supply at higher levels reduces this cascade and relieves price pressure all the way down. Empirical research indicates that this “filtering” process happens surprisingly quickly.

Supply skeptics may also fear that construction of new housing will exacerbate affordability problems by raising neighborhood rents or prices, fueling gentrification, and potentially displacing existing residents. New construction can have both positive and negative effects on prices or rents of nearby homes. New housing may an amenity that makes a neighborhood more attractive – and expensive. But it also absorbs demand and may reduce the incentive to upgrade existing housing to please high-end buyers. The evidence on the net effect of these effects is unclear. An important California study indicates that the production of market rate housing was associated with a lower probability that low-income residents in the neighborhood would experience displacement. But more research is needed.
The authors point to additional disadvantages of limiting supply, including pushing lower-wage workers to live in distant suburbs, where long commutes add to regional traffic woes and greenhouse gas emissions. They stress, however, that increased supply, while essential, is not sufficient to address the affordability challenge. Government intervention through subsidies and other measures is critical to ensure that housing supply is added at prices affordable to a range of incomes, and especially the lowest ones.

housing affordability market rate affordable housing more housing does reduce price Vicki Been

Written by Guest Writer September 2, 2019

Housing

Housing Production Plan Outreach Efforts

Arlington is in the process of update the town’s 2016 Housing Production Plan, and the Housing Plan Implementation Committee and Planning Department have put together a “meeting in a box” as part of their outreach efforts. The idea is to package a set of discussion questions and supplementary materials, so that groups can talk through the questions on their own and provide written feedback. Meeting in a box materials are available from the town website.

I tried this with a group of friends. Here are the questions, and points that came up during the group discussion. Notes that these are discussion notes (transcribed from large sheets of easel paper), and don’t represent agreement or concensus.

Question 1: Housing Needs. Arlington residents have expressed concerns about the housing needs of older adults. Other needs identified so far are the cost and condition of rental housing, the impact of Arlington’s housing sale prices on the ability of young families to find a home in Arlington they can afford, and the impact of limited housing choices on racial and ethnic diversity in Arlington. What housing needs are you most concerned about?

Address historical racial injustice and land use policies.
Diversity and types of housing. Availability and affordability.
Lack of diversity of housing types.
Every house sold is a total bidding war.
Better “stage of life housing” matches.
Having an adequate range of options for lots of different needs.
Impact on the regional housing shortage.
Arlington is served by the T and buses; we have a responsibility to provide housing because we have access to transit.
I was lucky to get in a few years ago, before prices started going crazy.
We spend too much time romanticizing our old crumbling houses with lead paint.
Arlington’s zoning encourages mansionization. As a result, we get one big expensive house rather than two smaller more affordable ones.
What’s happening in Arlington today is the same thing that happened to Lexington 20 years ago — it became a community for affluent professionals only
There’s too much emphasis on keeping things the way they were 20, 30, 40, or 50 years ago.
Housing can be about preserving economic diversity, but we need a variety of housing types to do that.
I’d be happy to see more people in town.
Getting an affordable rental unit here is like winning the lottery.
The suburbs have shut down housing production. That’s one of the things causing gentrification in Boston.
Arlington’s housing mainly caters towards families with children. For our town’s financial health, we also need housing for families without children.
With climate change, our practice of low-density, car-oriented, land-intensive sprawl is no longer sustainable. Density can be an important tool for addressing climate change, and we should use it to that effect.

Question 2: Challenges to Meeting Affordable Housing Needs. Participants in interviews conducted for the Housing Plan and at the June 9 Housing Plan Meeting were asked about challenges or obstacles to providing affordable housing in Arlington. Several challenges were identified, such as difficulty finding locations that for new housing development or redevelopment, how the Town’s Housing Trust Fund and CPA funds should be used to meet housing needs, and general tensions and disagreement about growth in Arlington that make it hard for people to agree. What challenges do you think are the biggest impediments to meeting housing needs in Arlington?

There’s not a stable funding source for Arlington’s Affordable Housing Trust Fund.
Housing is really expensive here.
There are not enough affordable housing developers that are willing to navigate Arlington’s anti-development stance. They’ll build in other communities, where there’s less resistance.
There’s a lack of political will to add affordable housing, or housing in general.
There’s not enough land where multifamily housing can be built.
There’s unreasonable resistance to new multi-family buildings, like apartments.
The housing production plan identifies a number of opportunity zones. But they’re small, and there’s not enough land to create much of an opportunity.
Our housing authority is not very aggressive about utilizing the land they have. Their leadership doesn’t seem to want to do it.
The belief that “Arlington is full”. In reality, we’ve just chosen to be (by virtue of current zoning).

Question 3: Opportunities for Reaching Agreement. What steps would help to bring Arlington residents together about providing affordable housing? How can the Town balance concerns about housing needs and natural resources protection? Or concerns about housing need and preserving Arlington’s built environment? What do you think most could people agree on?

Concern about exurban sprawl.
Concern about gentrification.
Our parking requirements make housing more expensive than it needs to be.
We can agree on worries. I’m skeptical that we’ll be able to agree on solutions.
There’s an unwillingness to accept incremental progress.
Many incremental changes feel too big.
If people feel threatened by affordable housing, they’ll oppose it.
Shared values around the importance of having residents of a variety of economic situations.
Do people really care about environmental sustainability when they move into a house? Not sure how you get people to sign on.
There’s a conflict between anti-density and sustainability.
If you don’t build here, there will be evergreen builds outside of 495.
Teachers who teach here should be able to afford to live here.
We need business growth and tax base growth.
New housing should feel like it blends into the surrounding neighborhood.
Our neighborhoods are changing. The fact that we’re not doing proactive things doesn’t prevent them from changing.

As you can see, our group had a range of opinions and even a few points of disagreement – for example, “there’s an unwillingness to accept incremental progress” vs “many incremental changes feel too big”. I feel like that pair is a good illustration of how different people have different comfort zones; a situation that can be challenging to navigate. Metro Boston is growing, as are metropolitan areas all across the country. Our new arrivals will need places to live, and I’d hope to see Arlington be proactive in addressing that need.

housing production Housing Production Plan Outreach

Written by Steve Revilak August 22, 2021

Housing Developer Math

Written by Barbara Thornton July 15, 2020

A modernist tiny house with bare wooden exterior walls.

Accessory Dwelling Units 101

Written by Guest Writer July 21, 2024

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:

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/
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.
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.

Affordability exclusionary zoning single family zoning districts sustainability town meeting warrant articles

Written by Steve Revilak January 28, 2020