In this rendering, a tree-lined boulevard allows for both pedestrian and autonomous vehicle traffic to safely intermingle. (HOK)

By the early 2020s, a significant number of cars with self-driving capabilities could be on North America’s freeways and city streets. Fast-forward to 2030 and 95 percent of U.S. passenger miles traveled could be served by autonomous vehicles (AVs) owned by companies providing transportation as a service (TaaS), according to the RethinkX research report Rethinking Transportation 2020–2030: The Disruption of Transportation and the Collapse of the ICE Vehicle and Oil Industries. This adoption of driverless cars will be life-altering for people from all walks of life—from those who currently cannot afford to own a car to millions of frazzled daily commuters.

Just as a century ago, when the arrival of the personal automobile fundamentally changed our society, the advent of AVs as our main mode of transportation will trigger another shift in people’s lives. To ensure that the changes will enhance the urban experience, cities and their private sector partners need to start planning for this new world.

Rethinking Parking

As car ownership evolves to a subscription service with intelligent fleets of AVs, land currently used for parking will become available for conversion to other uses. A McKinsey & Company report predicts that by the middle of the century, driverless cars will cut the need for parking in the United States by more than 61 billion square feet (5.7 billion sq m)—more than the entire state of Delaware.

Today, San Francisco’s central business district has 301 acres (122 ha) devoted to surface parking lots. AVs are narrower than conventional cars and, because they don’t have swinging doors and are guided by ultra-precise navigation technology, need as little as four inches (10 cm) on either side to park. Spaces in a self-parking AV lot could be 15 percent tighter, reclaiming 69 acres (30 ha) of valuable land in San Francisco for parks, community gardens, or buildings. This would also ease urban congestion, since a large portion of vehicles on city streets are drivers looking for parking. Likewise, dedicating entire parking lots at suburban office campuses to AVs would increase vehicle capacity while freeing up land for new development.

Think about the ubiquitous above-grade, freestanding parking garage. You see it in the suburbs and downtown, alongside your hospital, airport, university, shopping mall, and stadium. But developers of projects being planned today justifiably see these garages as dubious investments. As more people are driven to these places and events through subscription services like Uber or Lyft, managing the momentary but high-volume interactions and complex synchronizations at elongated curb spaces takes priority over the short-term storage of private vehicles at 180 square feet (16.7 sq m) per parking space.

A parking structure adapted for reuse as office space.

To prepare for 2030 and beyond, designers are envisioning parking garages as universal structures that, as personal vehicles (and the associated parking revenue) go away, can easily adapt to future commercial or residential uses on the same footprint.

Designing adaptive parking garages requires the input of site planners, architects, engineers, and interior designers, who must collaborate on an integrated design that encompasses everything from selecting the right site to designing a removable building enclosure. Other considerations include optimal structural rigidity, accommodating exiting requirements, and providing efficient MEP systems that will contribute to efforts to achieve carbon neutrality in future uses. Through this multidisciplinary collaboration, these garages can be designed as responsive facilities, ready to be converted into an office space, a hotel, shops, residences, or even a vertical farm.

Though incorporating flexibility for future conversion requires an upfront cost premium, this pre-investment will more than pay for itself. And down the line, it will allow an owner to avoid the need to tear down a garage and then navigate through a lengthy public planning process and the associated environmental impact report.

More of the street is dedicated to walking and pedestrian space as less space is dedicated to parking and driving. (HOK/Riggs Skepnek)

Living Streets

The impact of AVs on the built environment extends far beyond parking garages. Imagine a world in which land reclaimed from today’s streets actually contributes to a community’s broader culture and social fabric.

The arrival of self-driving cars brings opportunities to do much more than simply compress the size of streets, tweak curb heights, and regain a few feet of sidewalk space on each side. The 4.12 million miles (6.63 million km) of roadways in the United States, some of which pass through the country’s highest-value urban real estate, serve as an unparalleled land bank. As AVs leverage the “internet of things” to connect with the surrounding infrastructure, municipalities will be able to create truly universal streets.

Instead of approaching streets as places used almost exclusively for linear passage, planners will integrate pedestrians, cyclists, and AVs in radically different environments that promote health, well-being, culture, and commerce. These living streets of the future will become places that respond to adjacent development and that transform the first 30 feet (9.1 m) of space extending from buildings into an activity-filled, indoor/outdoor public realm.

Designed with “nature first” concepts, these next-generation streets will offer more area for permeable surfaces and bioswales to infiltrate and clean stormwater. The robust green space and tree canopy will offer fresher air, thermal comfort, and more room to express local culture while providing quieter, conversational environments. Living streets will be active environments that cater to walkers, runners, and cyclists. The streets will create outdoor areas for workplace meetings, new retail concepts, and expanded outdoor restaurant seating.

As these integrated streets become dynamic spaces for human activity and take the place of parked cars and vehicle lanes, planners will be better equipped to create dense, walkable cities with vibrant mixed-use districts—places that truly appeal to people of all ages.

Reducing the space dedicated to parking and through ways could allow for more greenery and seating. (HOK)

People-Driven Design

Affordable transportation, including van-sharing and driverless buses made possible through AVs, will open a new world of access—the fundamental decision maker for humans—to better jobs, health care, clean food, affordable housing, and high-quality schools for underserved segments of the population.

The people-first design approach enabled by AVs will be an open invitation for happier, healthier, and safer lives. By focusing on quality of life, planners can actively encourage positive health behaviors by improving the physical spaces that shape people’s routine choices, decisions, and actions. This also will create opportunities for real estate developers to tap into new markets made up of people seeking live/work/play environments.

Sharing the Road

The technology and safety considerations associated with AVs are constantly evolving. The age-old conflict between vehicles, cyclists, and pedestrians is growing in importance, with the advent of autonomous vehicles triggering a widespread revisit to many long-established safety standards that the U.S. Department of Transportation, NATCO, and similar organizations and agencies use as a basis to formulate vehicle design, driving control, and street design standards. The technology progression will be informed by the capabilities and limits of the rapidly evolving sensing technologies used by AVs.

Toes-in-the-Water Projects

As technology evolves and the move away from an auto-centric lifestyle emerges, AVs will provide unprecedented opportunities to reshape the built environment. Progressive developers, investors, municipalities, and transportation officials already anticipating this coming transformation are beginning to work with planners to future-proof projects and visualize how cities, towns, and suburbs previously planned to accommodate vehicles first can be redesigned for people.

For now, planners still need to work with state and federal agencies to develop new policies, zoning codes, and design standards that facilitate the creation of adaptive parking structures and universal streets. But there are many incremental land use changes that can start immediately. Planners are leaning into the rise of AVs by orchestrating the coming disruption to best assist in solving our most complex planning challenges: resilience, social equity, access, and public health. They are considering how to integrate AVs with existing public transit to broaden access to the system. And property owners are adding pick-up and drop-off lanes and adjusting on-site traffic flows for AVs.

HOK’s planning studio has developed research studies of projects including subdistrict showcases, university campuses, shopping centers, and large sporting and entertainment venues supported by AV loops or planned pathways that link to nearby transit connections. AV loops also can link single-family and low-density housing to transit-oriented developments and urban centers, potentially eliminating the need for park-and-ride garages and extending living-in-place options for an aging population with driverless transport to grocery stores, pharmacies, gyms, and cafés.

In coastal or seaport cities like Seattle, operating an AV fleet connected to ferry terminals could minimize the impact on terminal infrastructure and parking. This would allow for dense, highly compact development that concentrates people and services to limit sprawl in an ecologically responsible manner.

As we advance beyond these “toes in the water” projects over the years and decades to come, planners will have abundant opportunities to reclaim the public realm for a greater purpose—increasing the value of real estate assets while creating healthier, more equitable communities.

Brian Jencek is the codirector of HOK’s global planning practice. He is based in San Francisco. Jerome Unterreiner is a senior urban designer in HOK’s Seattle studio with an international portfolio of work focused on resilience planning.