But these prognostications miss what will be one of the biggest developments of all: In a world full of autonomous autos, transportation will become free. Not just hands-free, or driver-free, or go-wherever-you-want free. But free as in beer: complimentary, gratis. Summon a car and travel for nothing—that is, so long as you are willing to make a stop or two en route at sponsoring locations.

Picture a not-too-distant future where a trip across town is available to anyone who will spend 15 minutes in McDonald’s on the way. Not a fast-food fan? Then for you it’s Starbucks, a bookstore, the game parlor. Rides with a child stop at the Disney store, while teenage girls are routed via next decade’s version of Zara and H&M. Unlike today’s UberPool, with its roundabout routes and multiple passenger pickups, “UberFree” features tailor-made routes and thoughtfully targeted stops.