Currently, most roads in the U.S. are designed around the needs of drivers, making them inconvenient at best and dangerous at worst for walkers and cyclists. With more vehicles on the roads, pedestrian fatalities are surging nationwide. You’ve already heard that autonomous vehicles stand to make streets much, much safer by putting a computer fully in charge of the split-second road-reactions that human drivers so routinely flub. They might also succeed in upending an age-old vehicular hierarchy: In a world where most cars are driving themselves, pedestrians could reign supreme.
That’s the premise of new research by Adam Millard-Ball, a professor of environmental studies at the University of California, Santa Cruz. He uses game theory to suggest that autonomous vehicles could benefit pedestrians by being more responsive to their behavior. “In most urban areas, pedestrians have many more rights than they actually assert,” says Millard-Ball—for example, they don’t always cross when they’ve got the light, fearing a collision. Once self-driving cars arrive en masse, walkers might be more even assertive than laws generally permit.
Millard-Ball’s paper looks especially closely at the game of “crosswalk chicken” that human-driven cars and pedestrians often play: In the vast majority of states, pedestrians are supposed to be able to cross at all intersections, whether or not there’s a marked crosswalk, “but you'd be silly to try and assert your right in front of a car, because often drivers don't realize it’s a crosswalk, and even where there are some lines on street, drivers’ observance is often in the breach,” he says. So pedestrians usually end up the defense, watching for traffic before timidly lifting a foot off the sidewalk.
But with all the evidence that robots will drive far more safely and with greater adherence to the law than people, pedestrians’ incentives around safety will change. They may simply cross when they want to, confident that the vigilant AVs won’t touch them. Following that conclusion, Millard-Ball suggests that pedestrians may also be more empowered to jaywalk. Kids may play in the streets (like the olden days!). And cyclists may be more confident to “take the lane” and ride on streets without special bike lanes.
What will all of this freewheeling foot-and-bike movement lead to? Well, humans could essentially muscle their way onto the streets and slow vehicular traffic in urban centers. That might be a great thing if you think cities should never have had cars in them in the first place; transportation planners could respond to this new paradigm by engineering lower-traffic streets explicitly aimed at shared use, such as “woonerfs”—Euro-style, single-plane roadways used by peds, bikes, strollers, and cars alike. Existing walk-friendly planning policies would be reinforced.
On the other hand, if a city needs to keep vehicle traffic moving at a certain speed, Millard-Ball says that planners might also respond to a pedestrian-centric road hierarchy by separating uses as much as possible, possibly “removing crosswalks and corralling pedestrians to make sure they don’t get in the way of autonomous cars.” That could lead to roads with even higher speeds for vehicles with separate spaces for non-motorized traffic.
Fully autonomous vehicles are still years down the line, and experts believe it’ll be a decade or more before they appear en masse in dense, tricky-to-navigate city cores. Still, planners are already thinking about how they might transform urban space, and their effects will go beyond the implications proposed in this research. Shared autonomous vehicles may very well open up space in cities formerly allotted to roads and parking lots, encouraging infill development. Others bet that AVs will encourage housing sprawl by making it easier for people to live even further from work. And traffic may very well get worse, not better, if it becomes easier for a larger share of the population to avoid public transit and get around by car. As Henry Grabar recently pointed out at Slate, driverless cars will solve some old problems and create new ones. Whether they just reinforce 20th century development patterns or push cities to reinvent themselves more radically may depend on how well we plan now for their arrival.