UC Santa Cruz – or at least one of its professors – has raised an ominous warning of “robot gridlock,” caused when self-driving car algorithms realize it’s more efficient to keep circling than it is to seek out and pay for downtown parking:
Even worse, because cruising is less costly at lower speeds, self-driving cars will slow to a crawl as they “kill time,” says transportation planner Adam Millard-Ball, an associate professor of environmental studies at the University of California, Santa Cruz.
“Parking prices are what get people out of their cars and on to public transit, but autonomous vehicles have no need to park at all. They can get around paying for parking by cruising,” he said. “They will have every incentive to create havoc.”
Millard-Ball analyzes “The Autonomous Vehicle Parking Problem” in the current issue of Transport Policy.
Under the best-case scenario, the presence of as few as 2,000 self-driving cars in downtown San Francisco will slow traffic to less than 2 miles per hour, according to Millard-Ball, who uses game theory and a traffic micro-simulation model to generate his predictions.
“It just takes a minority to gum things up,” he said, recalling the congestion caused at airports by motorists cruising the “arrivals” area to avoid paying for parking: “Drivers would go as slowly as possibly so they wouldn’t have to drive around again.” Free cell-phone parking areas, coupled with strict enforcement in loading areas, relieved the airport snarls, but cities will be hard-pressed to provide remote parking areas for self-driving cars at rates lower than the cost of cruising—which Millard-Ball estimates at 50 cents per hour.
Regulation also falls short because, as Millard-Ball puts it, “It’s difficult to regulate intent. You can pass a law saying it’s illegal to drive more than 10 minutes without a passenger, but what if the car is picking up a parcel?”