Attendees of the AIA National Convention in Washington, D.C., saw a city largely transformed for the better since 1991, the last time we met in our nation’s capital. There was a lot to take in, from the forest of construction cranes towering over large swaths of the city to the gleaming, light-filled convention center itself. However, as an avid cyclist, I continue to be impressed by the designated bike lanes throughout the city and the phenomenal success of Washington’s tax-supported bike-share program.

Similar initiatives are under way in New York, Boston, Denver, and Miami. Even in my own hometown of Dallas, automobile, cycling, and pedestrian cultures are working through their differences, opening up avenues for alternative modes of transport. If this is more than a passing fad, then we’re approaching a tipping point that has profound implications for a host of issues, from public health to the health of America’s car manufacturers. As a citizen, I’m interested in all of these. As an architect, I’m struck by how this may play out in urban design and placemaking, in particular what appears to be a growing reappraisal of our streets as vital elements of the public realm.

Until the advent of the automobile, streets were shared common spaces that supported the needs of a broad range of users. With certain exceptions, these were not designed spaces. They might follow a pre-existing Native American trail or, if legend can be believed, the paths favored by cows in colonial Boston.

The automobile changed that in two interrelated ways. First, cars increasingly narrowed the function of streets as shared public spaces, which previously had accommodated multiple functions, including mass transit. Signage in the public realm—one of my particular concerns—became optimized for highway speeds, not the pace of pedestrians. In the years following World War II, it was axiomatic that streets belonged to motorists. This view of the street paved the way—literally—for a disastrous legacy: The slicing and dicing of our cities by limited-access interstate highways, the scarring of the urban fabric with surface parking lots, and the narrowing of sidewalks to feed the bottomless appetite for travel lanes and parking. Even municipal lighting was reoriented away from the pedestrian to the motorist cruising down the street.

It could have been worse. While I was in Washington, I walked over to the National Building Museum to see “Unbuilt Washington,” an exhibition of design proposals that never saw the light of day. One of the most incredible was a 1946 scheme to run freeways on both sides of the Mall. Residents and visitors eager to experience the landmarks of our democracy would have been relegated to tunnels to gain access to the vast lawn stretching between the Capitol and the Washington Monument. That this now seems outrageous is an indication of a welcome change in our perspective.

As the role of the automobile in designing our communities is increasingly challenged, architects have an opportunity to lead the way in reconsidering the possibilities of shared public spaces. This is not a special plea for those on bikes; it’s a call to our profession to consider an emerging body of clients who need the integrative skills of architects sensitive to how the parts of healthy communities hang together, including the experience we have in going from one place to another.To get the message out that livability is a design issue, the AIA is the proud sponsor of “The Cities Project,” a National Public Radio series on city life and urban issues. Tune in because people (and your clients) will be talking about it. The future of our cities is tied to our investment in them today and the design thinking of architects, as the NPR series will underscore, is integral to its success.

Join our conversation at aia.org/citiesproject.

Jeff Potter, FAIA, 2012 President