Yours truly, back in March:
Self-driving cars are one of the biggest threats to the future of cities, and widespread adoption could single-handedly undermine one of Baum-Snow’s most compelling arguments—commute times, which he says will be a driving force behind increasing urban densities. As incomes have risen for many city dwellers—those in the top 50 percent, at least—the value of their commute time has also risen. Given Marchetti’s constant, which says that commute times tend to hover around 30 minutes each way, snarled traffic will force the wealthy out of the suburbs and back to cities. In a sense, we’ve already started to see that.
But self-driving cars could reverse that trend. As people’s commutes are freed up for other tasks, including work, they’ll stretch their daily trips, once again allowing them to live where they want.