"No One at the Wheel," Samuel I. Schwartz, PublicAffairs, 272 pages, $30.

An appalling statistic appears toward the end of “No One at the Wheel,” Samuel Schwartz’s valuable primer on self-driving cars: In the century since the automobile arrived on the scene, 70 million people have been killed by it.

Schwartz, who served as New York City’s traffic commissioner in the 1980s, was nicknamed “Gridlock Sam” for his devotion to the conundrum of traffic. He knows everything about how cars and people don’t get along. This book — written in an earnest, conversational style — is his attempt to grapple with what he perceives as a fresh threat: driverless cars.

Schwartz’s is the first comprehensive analysis of what that will mean on the ground. Most likely, there will be far fewer fatalities. But cars that can drive themselves will bring with them other knotty societal problems.

Schwartz posits that as autonomous vehicles, or A.V.s, become more popular, they will restage the conflict between walking and driving. Schwartz is in it for pedestrians (and bicyclists).

“If history warns us about anything,” Schwartz notes, “it’s that pedestrians and cyclists have to be better organized, more vocal and more vigilant if they are going to ensure that A.V.s will not completely eliminate walking on many streets, except in fenced-in locations or at different levels from the roadway.”

Other factors to consider even before the robots take over include congestion pricing, which Schwartz forcefully supports for both human-driven cars and A.V.s.

We should heed Gridlock Sam’s advice as we move toward a future in which we largely surrender the wheel.