Logo IMG
HOME > PAST ISSUE > Article Detail


Leave the Driving to It

How would lives and landscapes change if every car had a computer in the driver’s seat?

Brian Hayes

The Open Road

The automobile has long been an emblem of personal liberty, particularly in American culture. With a car you can go where you want, whenever you want. Paradoxically, though, owning and operating a car is the most heavily regulated aspect of modern life. The car has to be registered and inspected; the driver has to be licensed; both of them have to be insured. You’re welcome to put the top down and go for a spin, but you had better obey the speed limit and the stoplights.

The layers of regulation would surely get thicker with computer-driven cars. When platoons of automated vehicles are driving in tight formation, weaving through cross-traffic on a millisecond schedule, every car has to trust all the rest to behave predictably. Before being allowed to join the traffic stream, each car would have to provide some assurance that its hardware and software are functioning correctly and have not been tampered with; this might be done through a cryptographic authentication protocol. A side effect is that tinkering with your car, except for the most superficial changes, would likely be forbidden.

Road transport might become more like the airline system. Major airports enforce a scheme in which flights are not allowed to depart until they have secured a landing “slot” at their destination—a place in the sequence of anticipated arrivals. An analogous rule could regulate access to congested highways or bridges; you couldn’t leave home until the road had room for you. The reward for submitting to this regimen of regulation would be faster and more predictable travel.

The operation of such a traffic-control system raises fascinating questions of social choice. Consider the case of cities connected by two parallel roads. Travelers free to choose their own route will presumably always take the road that minimizes their own travel time. But this exercise of free choice can contribute to congestion that delays everyone. An algorithm may be able to assign cars to roads in a way that outperforms the sum of everyone’s selfish choices. Would travelers accept such interference with their liberties? And how do we agree on the optimal outcome? What if a plan speeds up 99 percent of the cars, but the remaining 1 percent suffer a two-hour delay?

comments powered by Disqus


Subscribe to American Scientist