By Grace Mitchell Tada

Imagine a tool that banishes the social and environmental ills of modern urban planning and its suburban sprawl, instead constructing an approach that reconciles urbanism and environmentalism. Meanwhile, the tool also enables choice and equity in how and where individuals live.

Architect, urban designer, and DPZ CoDesign principal Andrés Duany insists such a tool exists. It’s the Rural-to-Urban Transect, at once a tool and a theory, and it’s a balm to the recklessly sprawling modern life now ubiquitous across the U.S., which takes the form of socio-economic uniformity, automobile dependence, and conspicuous land consumption.

The book Transect Urbanism: Readings in Human Ecology, edited by Duany and Brian Falk, who is director of the Center for Applied Transect Studies, presents a collection of essays and descriptive graphics that examine the Rural-to-Urban Transect and explains its potential to create both a better quality of life within communities and better environmental practices across all scales.

This transect identifies and allocates elements of urbanism and their suitability to varying environments. It’s a theory of human settlement: an “ordering system” that harnesses a geographic gradient to organize natural habitats, including human habitats. Every human activity, and its resulting element in the urban fabric, can be pegged to a locus somewhere along that gradient. These elements comprise an “interrelated continuum of natural and human habitats—natural, rural-sub-urban, and urban—with different settlement densities and opportunities for social encounter and human activity,” the authors write.

Though the concept of a transect was not defined as such until the 18th century, Duany describes it as a pattern of human settlement both timeless and cross-cultural: the rural-to-urban spectrum can be traced to settlements from ancient Pompeii to ancient China.

In the late 18th century, Alexander von Humboldt first articulated the transect in the modern sense. Joseph Meyer illustrated the concept, drawing Humboldt’s voyage to South America to include the natural habitat and conditions above and below the ground’s surface.

In the 19th century, Sir Patrick Geddes’ illustrated “Valley Section” incorporated human presence in varying habitat zones. The humans, per the times, always exploited their environment.

In 1969, Ian McHarg posited the next seminal transect. Duany finds it incomplete: it failed to include, or even suggest, human habitat. Moreover, this absence perpetuated the dualism between human and nature that underpins environmental thinking — “nature is sacred, and the city profane.” This dualism ultimately produced the chasm between environmentalism and urbanism.

In practice, McHarg-inspired planning has yielded countless communities that prioritize preserved “environmental” areas at the expense of higher density. For example, South Carolina’s Hilton Head and California’s Sea Ranch sanction only single-use zoning. “The developed areas of these projects remain, in their socioeconomic and environmental performance, indistinguishable from sprawl: everyone drives everywhere for everything,” Duany and Falk write.

In 1994, the transect was revitalized as an ordering system at the Congress for the New Urbanism (CNU), when the group — proponents of “density, connectivity, and contiguity” — sought a theory establishing connections between elements of urbanism. The Rural-to-Urban Transect did so by defining six recognizable transect zones and their interrelationships: Natural (T1), Rural (T2), Sub-urban (T3), General Urban (T4), Urban Center (T5), and Urban Core (T6).

Duany asserts that the Rural-to-Urban Transect extends “the environmental protocol of McHarg into the city,” thus including people. It becomes a tool with which to design, correlating elements along a rural-to-urban continuum, enabling “the basis for a system of zoning that creates complex, contextually appropriate human environments.” Adapted from landscape ecology, each of the six transect zones contain elements that engender and amplify a place’s character.

This transect’s extension of the McHargian protocol yields arguably two of its greatest boons: its potential to unite environmentalism and urbanism and its capacity to support diverse, equitable communities. The divide between humans and nature is not new — Duany traces this chasm back to the Old Testament — and it manifests in the 20th century as environmentalism’s defensive stance toward urbanism.

The dominant ecological disposition “privileges a pristine nature and regards the presence of humans as a disturbance” to a system understood according to its pre-human condition. “A good human community can be ‘green’ only by being invisible,” Duany and Falk argue. Urbanism has thus been viewed as “a negative condition, never as an organization of positive choices for the improvement of human communities.” And as a result, environmentalism is expressed in technical and regulatory systems that promote suburbanization — from pervasive landscaping to mandated on-site stormwater treatment.

This paradigm fails communities when prioritizing nature means seeing “social space as blight.” “Whole communities of humans have been pushed aside for highway construction, but certain fish and fowl have caused even the most single-minded transportation department officials to reconsider their designs,” Duany and Falk contend. But only certain communities get pushed aside. Favoring nature also usually translates to favoring certain social and racial groups at the expense of others.

According to the authors, their Rural-to-Urban Transect can mitigate these insidious tendencies. Rather than holding economy and culture as beyond nature, this transect accommodates all elements, rooted in the belief that humans are essential to environmental discourse, in all their various lifestyles along the rural-to-urban spectrum.

Most importantly, Duany and the other authors include everyone in their conception and explicitly those who historically have had little choice in how they live. Systems based in the Rural-to-Urban Transect encourage a plurality of viewpoints and human habitats. They promote equity.

Key to the Rural-to-Urban Transect is its basis in form. Many planning initiatives are based in use and therefore manifest as prohibitions and separation. Cities filter community-making through a sieve of engineering standards, zoning ordinances, and other regulatory mechanisms long before designers enter the scene. Duany asserts that this existing framework, however, can be re-imagined by their transect: zoning based in form can yield certain physical outcomes and settlement patterns. Rather than zones that simplify and separate, transect code ensures fruitful relationships and adjacencies, from the local to regional scale. Transect-inspired zones preserve character and diversity according to place.

Essays in Transect Urbanism explain how these successes of the transect can be achieved: one details how to analyze an urban transect, one discusses governance along the transect, another discusses retail models within it. Duany includes a chapter describing the transect-based SmartCode that he has developed and implemented across various cities. Another chapter gives hope that existing sprawl can be repaired into a paradigm more resilient. Other essays consider the Rural-to-Urban Transect ontologically: the reason for six zones, and whether it qualifies as natural law, as certain people — Duany included — claim. The range of essays, from the practical to the theoretical, and the extensive illustrations make it a book suited for the student and the professional, for the planner, the landscape architect, and others thinking critically about the built environment.

As of 2019, the Form-Based Codes Institute identified 439 transect-based codes that had been adopted worldwide. Clearly, more communities do not embrace such thinking than do, and our society has much work to accomplish before divorcing itself from suburban sprawl. Duany in part blames the theory of landscape urbanism, which he claims perpetuates sprawl through the guise of aesthetics. He argues: “human biophilia is such that an image of anything with leaves will tilt the selection in its favor.”

Certainly, though, criticisms of the Rural-to Urban Transect arise: it is too simplified; its mere six zones are insufficient to account for all settlement and natural area types; the intentional rules of its zones are undesirably prescriptive; or it lacks consideration of urban ecology and biodiversity.

Yet, as made by the case presented in Transect Urbanism, the Rural-to-Urban Transect can serve as a noble tool in the reformation of our urban fabric. In one of his essays, written in 2005, Duany warns that a failure to square environmental ethos and social equity concerns with free market choice as perpetuated by the status-quo sprawl may only be solved by “a long economic emergency…that none of us should wish upon the nation.”

As millions of Americans grapple with job and home losses, among many other kinds of loss, we’re in the midst of an emergency. Released into a pandemic climate that has made us skeptical of dense urbanism, this book arrives with special urgency.

Now is as ripe a time as ever to give a different paradigm a chance, even if doing so will also require specific and convincing accommodations to the moment.

Grace Mitchell Tada, Associate ASLA, is with Hood Design Studio and co-editor of the new book Black Landscapes Matter.