(p. B2) With remarkable consistency, the research finds the same thing: Whenever a road is built or an older road is widened, more people decide to drive more. Build more or widen further, and even more people decide to drive. Repeat to infinity.
Economists call this latent demand, which is a fancy way of saying there are always more people who want to drive somewhere than there is space for them to do it. So far anyway, nothing cities have done to increase capacity has ever sped things up.
The extent of this failure was chronicled in a 2011 paper called “The Fundamental Law of Road Congestion,” by the economists Gilles Duranton, from the Wharton School of the University of Pennsylvania, and Matthew Turner, from Brown University.
The two went beyond road building to show that increases in public transit and changes in land use — basically, building apartments next to office buildings so that more people can walk or bike to work — also fail to cut traffic (or do so only a little).
This doesn’t mean public transit and land planning are bad ideas, or that widening freeways is a bad idea. When roads are bigger, more people can get around. More people see family; more packages are delivered; more babies are lulled to sleep. It just means that none of those measures have done much to reduce commute times, and self-driving cars seem unlikely to either.
That’s where charging people during busy times comes in. “Maybe autonomous cars will be different from other capacity expansions,” Mr. Turner said. “But of the things we have observed so far, the only thing that really drives down travel times is pricing.”
This is because the average person prefers the privacy and convenience of riding in a car.
. . .
“This idea of congestion pricing is not completely dismissed the way it once was,” said Clifford Winston, an economist at the Brookings Institution.
Mr. Winston said the eventual introduction of self-driving cars would probably lessen consumer opposition to paying more to use roads during peak periods. Ride-hailing apps have taught consumers to accept surge pricing, and people are generally less resistant to paying for something new. The result would be something like variably priced lanes dedicated to fleets of robot vehicles.
If that happens, one of the hidden benefits of this revolutionary new technology will be that it got people to accept an idea that economists started talking about at least a century ago. And you get home a half-hour earlier.
For the full story, see:
Conor Dougherty. “A Cure for Traffic Jams.” The New York Times (Weds., March 8, 2017): B1-B2.
(Note: ellipsis added.)
(Note: the online version of the story has the title “Self-Driving Cars Can’t Cure Traffic, but Economics Can.”)