There are plenty of documented problems with autonomous cars, from road safety issues to worries about job losses. But a new study raises a concern that hasn’t been considered much before: that autonomous cars could cause severe traffic jams by cruising around to avoid parking fees.
Transportation planner Professor Adam Millard-Ball of the University of California, Santa Cruz, has been researching the way that autonomous vehicles would respond to parking situations. And in a new study he points out that autonomous vehicles don’t have the same incentive to park as do manually controlled vehicles. When a driver arrives at their destination, they necessarily have to park their car. But an autonomous vehicle can keep cruising around once its passenger has disembarked, and it may be incentivized to do so by parking costs.
This is particularly a problem as increasing parking fees is a key way to reduce car usage in cities and encourage people to use public transport, which is better for the environment. But an autonomous vehicle can kill time by driving at a low speed that is less costly to maintain. This leads to a situation where it is cheaper for the vehicle to keep moving even when a space is empty than to pay for parking.
“Even when you factor in electricity, depreciation, wear and tear, and maintenance, cruising costs about 50 cents an hour — that’s cheaper than parking even in a small town,” Millard-Ball said in a statement. “Unless it’s free or cheaper than cruising, why would anyone use a remote lot? … [Autonomous vehicles] will have every incentive to create havoc.”
Millard-Ball used a traffic microsimulation model based on real data from downtown San Francisco and came to the worrying conclusion that autonomous vehicles could double vehicle travel to, from, and within dense urban centers.
He does offer a potential solution, albeit one which may not be popular with drivers. He suggests that congestion pricing, in which motorists pay a flat fee to enter a busy city area, can reduce congestion on the streets and avoid gridlock. A system like this exists in cities including London, Singapore, and Stockholm. To prevent autonomous vehicles from gumming up city streets by cruising, he suggests a time-based charge for occupying public spaces which applies whether the vehicle is parked or moving, which would take away the incentive for autonomous vehicles to cruise.
The study is published in the journal Transport Policy.
