Act: Inspiration

The American Alley, Part 4: Rediscovering the Forgotten Human Scale

August 27, 2021

Ed. note: You can read Parts 1, 2, and 3 on here, here, and here.

There is a human scale that has been forgotten here in America. Perhaps more than anything else, it is the human scale that so captivates Americans walking historic European cities. Because in almost all cities and towns across America, that human scale doesn’t exist anymore—to the extent that it ever did.

The cities of the New World were laid out with wide, straight roads. The short, narrow, and curving medieval streets colonists left behind in Europe were understood to be unhealthy, fire-prone, inefficient, dirty, stinky, and to be avoided if at all possible. And medieval streets were certainly all of those things. But they also reflected the human person in a way that the master-planned city streets of America did not.

Two defining characteristics of the modern streets, specifically in America, are: (a) their vast width and length in relationship to the pedestrian, and (b) their lack of spatial definition. For example, when Philadelphia was laid out in 1681, streets were platted at 100 feet wide and 50 feet wide. William Penn, unconcerned about creating a continuous street “wall,” encouraged buildings to be placed in the center of their lots. The streets of Philadelphia were arranged in a grid, creating an endless view to the horizon.

Though the “Forgotten Human Scale” never existed in most American cities, when we experience it now, we get a sense of belonging and of home. The Forgotten Human Scale awakens something deep within us.  It reflects the movement of a child and the pace of a pedestrian rather than that of the car. Its approachable size reflects the proportions of the human body. It responds to the human eye by containing space with continuous street walls. And it feels like a room of the public realm in a way that typical American streets do not. My wife Rose, who is originally from the Netherlands, describes the feeling one gets in these places as gezelligheid. She says there is no direct translation but when used to describe minor streets, it means “belonging” and “cozy” and “the feeling of home.”

In contrast, modern American cities are built along wide roads. Fire trucks and other emergency vehicles, trash trucks, delivery vehicles, parking, and traffic—all flow along wide roads.

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The broad, tree-lined American residential is a pleasure to live and walk along. But wide roads also make possible adjacent narrow streets, and the urban fabric is enriched by the contrast. In Philadelphia, as we saw earlier in this series, the juxtaposition between the wide and the narrow offers a rich and diverse urban experience.

The Opportunity Presented by ADUs

Today, more and more homeowners across the country are considering building accessory dwelling units (ADUs). Those wanting to build ADUs along alleys are presented with a choice: to accept the current condition of the alley, or to construct ADUs as part of a streetscape that fronts the alley and forms the Forgotten Human Scale in our towns and cities for the first time.

But there is some work to do first. Over the last few years, legislation has been passed by municipalities across the country promoting the development of ADUs. Yet for urban areas with alleys, ADU codes have only imagined the alley as it is now: an undefined space characterized by parking lots, garage doors, and chain link fences.

ADU lowered into a backyard.

ADU lowered into a backyard.

Panama Street; minor street of Philadelphia.

Panama Street; minor street of Philadelphia.

ADUs are like Uber. Uber empowered individuals to capitalize on their privately owned investment of a car that sat parked over 95% of the time. Over the last century, the vast majority of municipalities in America made it difficult or illegal outright to build a second dwelling in the backyard of a single-family home. But recently, legislation legalizing ADUs has swept across the country, west to east. On January 1, 2017, California passed legislation to begin the process of legalizing ADUs statewide. California coastal cities saw the potential value of real estate drastically change, and Silicon Valley startups are doing their best to seize the moment. Today, if you Google “ADU startup,” you will get results like Rent The Backyard, Abodu, United Dwelling, Dweller, OBY, Homestead, and others. The majority of these startups offer to finance, permit, build remotely, install, and manage the ADU as a rental—and with unbelievably fast timelines. In effect, they are allowing you to make your backyard cash positive within a couple months and just a few clicks on your phone.

It is yet to be seen if any of these startups will succeed, given their current business models. The complexities of construction are a huge barrier to modular construction and the exponential expectations of the tech world. Perhaps a business model will emerge to finance and streamline the paperwork and potential management side, while empowering local builders to actually do the construction.

For many West Coast cities, there are few or no alleys, and the addition of a modular ADU to a private backyard will be a valuable way many people can capitalize on their backyard resource.

For backyards that do front onto alleys, though, there is another resource that should be recognized: the historic American service alley. In the previous articles in this series, I pointed out that the inner-block, and specifically the alley, is perhaps the only place in existing American towns and cities today that will allow the development of pedestrian-scaled urban spaces. Transforming underutilized service alleys into minor streets could form a secondary street network designed around walking and biking. The construction of ADUs along alleys offer a unique opportunity to begin the transformation of a humble service alley into a much-loved minor street.

The Problem: Current ADU Codes Do Not Recognize the Alley as a Resource

Most alleys in America are not pleasant enough to inspire homeowners to voluntarily face them with their new accessory dwelling unit. Those writing guidelines for ADU legislation are concerned with parking requirements and possible negative impacts to the main house and main street. But as far as I have seen, they never consider the design guidelines for the alley. Without such considerations, ADUs being constructed today will not only fail to transform the alley into a minor street, but will arguably degrade the alley in ways that prompted zoning codes to ban them a century ago.

In Appendix A of the e-book for this series, I lay out some of the design principles of the most-loved minor streets—principles of buildings arranged and built to form space, at a pedestrian scale, by buildings characterized by durability, beauty, and utility. Modern architectural design has lost the sensibilities and the context for pursuing these time-tried values. Instead, buildings are conceived as standalone objects (anti-spatial) and they are not placed so as to create formed space. The ADUs being offered by today’s building companies, and more importantly the eventual placement of these ADUs, are no different. When advertising their models, companies naturally place them in a remote natural landscape. That is because the designs were never intended for the urban realm. Intuitively, homeowners pull the new ADU away from the alley in an attempt to find a little more privacy for the large modern windows.

Prefabricated ADU displayed in the environment it was designed for.

Prefabricated ADU displayed in the environment it was designed for.

The same ADU being forced into the messy environment that characterizes backyards and alleys.

The same ADU being forced into the messy environment that characterizes backyards and alleys.

However, even these modern ADUs, designed to be placed in isolation in nature, could be arranged (along with garden walls, outbuildings, and hedges) along an alley in such a way that they transform the alley into a lovely pedestrian-scaled street. An Alley Form-Based Code should be written in tandem with ADU legislation that would encourage the principles of the most beloved minor streets.

Creating the Most Beloved Minor Streets Today

It is unlikely that modern ADU construction will replicate the density of the minor streets of the past. For one thing, quality of life in the private realm of the home has improved. The history of minor streets in America points to the fact that they were developed in part as a response to housing demands that required extreme urban density. It could be argued that many American minor streets were overdeveloped to their own detriment and that individual houses often lacked a comfortable amount of light, air, and privacy. While there is a housing demand in many cities in the United States today, it is not at the level that it was in the early 1800s.

In Appendix B of the e-book, I demonstrate that the principles of the most beloved minor streets can be achieved at a much lower density of dwelling units to street frontage. The diagrams there seek to uphold the improved quality of the modern “private realm,” while at the same time following the principles of the most beloved minor streets (“public realm”).

Since each property along a residential alley is privately owned, the transformation from “alley” to “minor street” requires each owner to participate to at least some degree in this shared vision. The alley will not be ”spatial” or feel like a street if more than just a few of the lots do not build along it. Given the significant financial barrier to ADU construction, as well as the number of different properties (and thus property owners) that often back onto an alley, this seems like an almost impossible barrier to overcome. Below are four possible approaches:

1. Legislation Promoting Street Walls Along Alleys (Space Formed by Homeowners)

New codes and ordinances could make huge strides toward this transformation by encouraging property owners to build a garden wall, plant trees or hedges, or otherwise delineate a common “street wall” along the edge of the alley. If a simple Alley Form-Based Code required garden walls to be built high enough to provide privacy to both the alley and the backyard, and limited the size of the openings off the alley, this alone could form the alley into a lovely urban space, extending the public realm of the city.

2. Subdividing and Developing Along the Whole Alley (Space Formed by Single Developer)

The simplest way to develop residential buildings along alleys would probably be for cities to allow homeowners to subdivide their properties parallel to the alley. This is the historic outcome of the mews of London, which were initially ADUs of the main house and then later subdivided. A developer could hypothetically buy out the inside of a residential block and develop a complete minor street. While this is perhaps the most straightforward way to create a “most beloved minor street,” there are significant values created by the relationship of primary home to ADU, and I believe the best minor streets will be created by many hands and minds over a much longer period of time than a typical development today. That being said, Daybreak Mews by Opticos Design is an excellent example of just this type of development.

3. Development of a Pedestrian Court Through the Block (Space Formed by Single Developer)

Exterior “urban space” should feel like a room, with identifiable edges. The first incremental development adjacent to alleys will need to form both sides of its own space. This could be as simple as developing on two adjacent lots, creating a pedestrian court that connects the front street to the alley or another front street. Croskey St. Mews (1964) in Philadelphia, Warren Place Mews in Brooklyn (1870s), , and Euclid Mews (1980), and Kalorma Mews (1974) in Washington, DC, are a few good examples I have visited. The following study explores this inner-block development type. In time, if the alley is transformed into a minor street, a beautiful juncture may appear where the minor street and pedestrian court meet.

4. ADU Legislation as Part of an Alley Form-Based Code (Space Formed by Homeowners and Incremental Developers; i.e., “The Swarm”)

Most importantly for this research on minor streets and alleys, new ADU legislation could provide design guidelines to encourage principles of the most beloved minor streets for new ADU construction when built in blocks with alleys. The construction of new ADUs has the potential to radically improve the civic realm of the city. ADU legislation is being adopted by municipalities across the country. In West Coast cities that first passed ADU codes, significant investment can already be seen in the building of thousands of new ADUs. Towns and cities of traditional blocks with alleys have the opportunity to craft a simple, Alley Form-Based Code, based on principles of the most beloved minor streets (see: Appendix A of this series). The code could then accompany new ADU legislation so as to set the stage for the transformation of the service alley into a minor street and bringing the “forgotten human scale” to American cities for the first time.

“Alleys are richer, more flexible, and more subject to creative social interpretation than the frontage street. They will play an ever-greater part in the future of New Urbanism.” —Andres Duany

“Alleys are richer, more flexible, and more subject to creative social interpretation than the frontage street. They will play an ever-greater part in the future of New Urbanism.” —Andres Duany


From where I am sitting writing, I can look up at the wall of my studio where I have pinned figure grounds of West Chester, Pennsylvania, where I live, along with Bruges, and Rome. All are at the same scale. The city plans are remarkably similar in size. The juxtaposition allows me to reference the scale and sequence of urban spaces from beautiful cities I know well, and compare them with the city I live in.



There is a vast divide between the gridded layout of a traditional American town and the rich diversity of piazzas and human-scaled streets that make up cities such as Rome and Bruges. It is hard to imagine creating a highly spatial piazza or European street in the grid of West Chester. Private property rights and zoning regulations found throughout the United States make the feasibility of that transformation even more impossible.



West Chester will never be Rome, and I wouldn’t want it to try. Instead, I keep these images on my wall because of the humanist values that are implicit in the figural layout. The figure grounds of Rome and Bruges show the size and sequence of piazzas, and the width and length of streets that make up the public realm of the city. The character of these cities, and the piazzas and streets which shape them, are very different. However, they were composed at the scale of the pedestrian and the human eye.

West Chester.

West Chester.

When I look at the existing residential alleys in West Chester, when I consider the fact that all the property fronting the alleys is privately owned, when I think about all the zoning codes that have made “missing middle” alley structures illegal in my town, when I consider a Borough Council whose greatest concern is providing off-street parking, and when I remember the host of bureaucratic roadblocks faced by would-be incremental developers—I start to envy the greenfield developers. Then I wonder if the goal of creating beautiful, human-scaled places in America is unachievable, and that perhaps I should just try to move to Rome. But as the great R. John Anderson has written, “Brooklyn doesn’t need your ass,” and I am sure Rome is fine without mine.

And thankfully there are other values at stake. My wife Rose and I are working hard to make our townhouse a home, and our small children are blessed to have grandparents just a couple blocks away. I will stick here in West Chester. I have intentionally committed to the place where I live and that I love, and I have chosen to help it mature into a place that is more beautiful, more lovable, and more prosperous.

And, despite the potential roadblocks, this is a very exciting time to live in a town or city composed of urban blocks with alleys. New ADU legislation is opening up the door to developing the alley and the inner block for the first time in a century. The inner block—which for traditional towns and cities is full of human-scaled courts, passages, narrow streets lined even narrower townhouses, and more—is finally being noticed in the United States. American demographics are changing and so are its housing needs. There is a market demand for small rental housing options in walkable urban centers. Our oldest neighbors are asking for housing options other than the institutional car-centered ones available now. “Human scale” is valued more, and the auto-oriented scale (and price tag) valued less.

It is time that we recognize that the potential for spatially formed, human-scaled, beautiful, and prosperous urban places already lies within every urban block.

All images provided by the author.

Thomas Dougherty

Thomas Dougherty works as an architect in West Chester, Pennsylvania, where he lives with his wife Rose and three children. He holds a Master of Architecture and a Master of Architectural Design and Urbanism from the University of Notre Dame.

Tags: building resilient cities, New Urbanism, walkable cities