THE DIRT

Over four days of the Congress for New Urbanism (CNU) in Savannah, Georgia, autonomous vehicle (AV) optimists and pessimists presented their hopes and fears about the coming technology-driven transportation revolution. AVs can either increase speed and efficiency and reduce transportation costs, or create more congestion and sprawl, kill off public transit, and increase transportation inequities. AVs will be coming in the next few years, or won’t be seen in most places for a few decades. AV ride share companies like Uber, Waymo, and Lyft only have our best interests at heart, or they are self-serving and want to remake streets to optimize for AVs, to the detriment of other modes of transit. AV companies can be given a long leash and work with state or local governments in partnership, or these companies need to be closely regulated.

Amid the broad debate by planners, landscape architects, architects, and traffic engineers that happened across multiple sessions, possible benefits and dangers of AVs became clear, as did the shape of solutions to possible problems.

Possible Benefits

Gerry Tierney, director of Perkin + Will’s Smart Mobility Lab, thinks AVs will enable cities to create narrower car lane widths — just 8 feet instead of the usual 10 or 12. AVs are expected to communicate with each other to increase efficiency and speed, forming a platoon. With this scenario, “headway between vehicles will be shortened, increasing the capacity of streets by two or three times.”

Tierney thinks we can give that extra road space created by AV platoons over to the public realm. “We can create new mixed-use lanes for bikes, e-bikes, scooters, and e-scooters, along with widened sidewalks, and green infrastructure.”

In an analysis of San Francisco’s streets, Tierney found that green space in transportation networks could be increased by 42 percent with the reduced lanes for AVs, spreading 1.3 Golden Gate Park’s amount of greenery throughout city streets.

Car companies will soon offer subscription services so that car ownership — and the number of cars on the road — will decrease. Today, the average car is only used 4-5 percent of the time. With subscription services for AVs, utilization rates will increase to 96 percent. “Fleet size can be reduced but carry the same number of people.”

AVs could be parked in towers, reducing the need for homeowners to purchase a parking lot, which can add 24 percent to the cost of a unit in a city like San Francisco. Parking will plummet, freeing up space for Amazon deliveries and reducing congestion.

According to transportation planner Patrick Seigman, some 80 percent of the cost of taxis are the driver. As such, AV rideshare “taxis” — like Uber or Lyft — will cause the “cost of taxis to plummet.” With buses and trains powered by autonomous technologies, the cost of transit could also further decrease.

Autonomous rapid transit (ART) could further increase road capacity. Tierney imagines 20-seat shuttles on dedicated lanes. Siegman pointed to self-driving shuttles now in use in Switzerland and Las Vegas, which have a top speed of 25 miles per hour. Instead of a driver, they have a conductor who can only push a stop button.

Possible Dangers

Peter Calthorpe, a leading planner, said that “autonomous vehicles will mean death for cities.” He said single-passenger ride share travel 35 percent more miles than regular vehicles, and AV shared taxis can be expected to travel 30-60 percent more miles, and AV single taxis, 50-90 percent more miles. “Dedicated lanes for AVs will only increase sprawl as private vehicles travel farther.” Furthermore, given speed is of the essence, “people won’t share — there’s no time advantage to sharing.” With AVs, “vehicle miles traveled will double and roads will become impassable.”

Tierney worried that AVs could create a “two class system” — those with access to AVs and those without. “We could imagine people playing video games in a Mercedes Benz subscription AV while those who can’t afford are then starved of transit options.”

Architect and urban design Kevin Klinkenberg, said in Savannah, Georgia, Uber and Lyfts can be expensive if you aren’t just taking a short trip downtown. “Even if AVs cut the cost by half, there is still a large section of the population who won’t be able to afford them.”

Transit rides are already subsidized and are losing money in many places; AVs can therefore put further pressure on strapped transit systems, speeding up the killing of routes.

He also wondered who will pay for all the beautiful, green, multi-modal, AV-optimized streets, so often seen in renderings? “With AVs, where will the money come from?” Most cities are already completely strapped and can’t fix potholes on time.

Christopher Fornash, a transportation engineer with Nelson/Nygaard, thinks it will be 20-30 years before we see “pervasive autonomy.” He imagines autonomous cars, buses, and trains, with inter-connections. But Tierney wonders where pedestrians will go in this system? “If you have AV through-ports for efficiency, how does a pedestrian cross the street? I hope not bridges.”

Fornash worries that AV companies have already pre-empted city regulation of AVs, because in 10 states, “it’s too late, city right of ways are now in state control. AV companies now have the ability to use streets on their own terms.”

According to Klinkenberg, the transportation system is controlled by a small number of engineers, policymakers, and companies. “It’s not open to political or economic feedback. There will be the same result if you add AV to the mix. We’re just swapping new technology into the same system.”

Possible Solutions

Tierney said it’s important for planners and policymakers to “design around community values and prioritize road access. We need to reverse engineer these systems and design for what we want. There is an opportunity to reclaim cities from the car.”

Alex Engel, program manager with National Association of City Transportation Officials (NACTO), which just released the smart Blueprint for Autonomous Vehicles, said “we can’t let the private sector dominate the conversation about AVs. We need to produce public policies that shape outcomes. We need to use good data and code the curb.”

Calthorpe called for instead investing in autonomous rapid transit (ART), like bus rapid transit (BRT) but with more nimble vehicles, which is already up and running in Zhuzhou, China. “If ART have dedicated lanes, autonomous vans or buses could be 30 percent faster than BRT and cost 80 percent less because there would be no drivers.”

Siegman calls for restoring control of streets back to local areas, giving cities and communities the right to “charge right prices for curb access and parking, and driving on streets.”

As an example, he pointed to San Francisco airport, which now charges taxis and ride share a $7.60 fee for accessing the curb for drop-offs and pick-ups in the most convenient zone, but half the price for access to a less convenient spot at the top of a garage.

Cities could charge riders of AVs for pick-ups and drop-offs in order to finance equitable access to public transit, including low-cost ART, and green street improvements.