In No One at the Wheel: Driverless Cars and the Road of the Future (PublicAffairs, Nov.), Schwartz, a former New York City traffic commissioner, explores the promise and perils of the widespread use of autonomous vehicles, or AVs.

What are the biggest misconceptions about driverless cars?

There are two opposing camps regarding driverless cars—they are both wrong. AVs should work in all settings by the second half of this century. The nonbelievers are akin to those who pledged not to set foot in a “driverless” elevator. It took almost a half century, but nearly all elevators today are autonomous. The evangelicals say full steam ahead, and if you slow the process down you’re killing people. But if we fully adopt AVs and get the technology wrong, more people may die as vehicle miles traveled climb, which increases the potential for crashes, and people’s lives will become more sedentary, resulting in more deaths than AVs may save. Lancet estimates that over five million people die worldwide from being physically inactive each year versus about 1.3 million from car crashes.

How would traditional mass transit be affected?

If we are smart, AVs will complement, not compete with, good public transportation. A best outcome would be for shared AVs to efficiently pick up people from transit deserts and drop them off at train and bus stations to whisk them to central business districts and other dense areas. But if we aren’t smart and buy into the false argument that single-occupant driverless cars can form an AV train by traveling in closely spaced platoons, we will decimate public transit. This could retrigger the very painful cycle that began in the 1930s with the car industry destroying many transit systems in the U.S., which, with help from the highways-will-solve-all evangelicals, led to the hollowing out of many cities, soaring crime rates, destruction of many solid communities—often predominantly minority and/or low income—and an extensive decline in quality of life for city dwellers.

How might private autonomous vehicles reduce personal interactions?

I recently saw a promotional video in which the AV car transformed itself into every room of the home. At night, one could sleep in it; during the day it became an office; in the evening, a living room with a wide-screen monitor for TV watching or virtual meetings. Why ever leave this cocoon? Drivers over the past 50 years have gotten lonelier and lonelier without AVs. When I started studying transportation at graduate school in 1969, the average car carried about 1.4 people on the commute to work; today it is under 1.1 and the drive has gotten much longer. Studies have shown that those with few social interactions suffer from more physical and psychological illnesses and have shorter life spans. I know of no one who is calculating the potential cost of the greater isolation we may experience as our cars become essentially our homes.