Driverless taxicabs, almost certainly coming to a city near you, have freaked out passengers in San Francisco, Phoenix and Austin over the past year. Some documented their experiences on TikTok.

Octogenarians, startled by the empty front seats during a ride to a coffee shop in Phoenix, for example, and a rider named Alex Miller who cracked jokes through his first Waymo trip last spring. "Oh, we're making a left hand turn without using a left turn lane," he observed. "That was ... interesting."

The nervous laughter of anxious TikTokers reminds historian Victor McFarland of the pedestrians who yelled "Get a horse" to hapless motorists in the 1910s. But McFarland, who teaches at the University of Missouri, says the newfangled beasts known as automobiles were more threatening and unfamiliar to people a century ago than driverless cars are to us now.

"Automobiles were frightening to a lot of people at first," he says. "The early automobiles were noisy. They were dangerous. They had no seatbelts. They ran over pedestrians. "

Some people also felt threatened by the freedom and independence newly available to entire classes of people, says Saje Mathieu, a history professor at the University of Minnesota. They included Black people whose movements were restricted by Jim Crow. Cars let them more easily search for everything from better employment to more equitable healthcare, as could women, who often seized opportunities to learn how to repair cars themselves.

And, she adds, cars offered privacy and mobility, normalizing space for sexual possibilities.

"One of the early concerns was that the back seats in these cars were about the length of a bed, and people were using it for such things," Mathieu explains.

Early 20^th century parents worried about "petting parties" in the family flivver, but contemporary overscheduled families see benefits to driverless taxis.

"If I could have a driverless car drive my daughter to every boring playdate, that would transform my life," Mathieu laughs. She says that larger concerns today include numerous laws that can be broken when no one is at the wheel. Who is liable if a pregnant person takes a driverless car across state lines to obtain an abortion, for example? Or when driverless cars transport illegal drugs?

A century ago, she says, people worried about the bootleggers' speed, discretion and range in automobiles. And back then, like now, she adds, there were concerns about the future of certain jobs.

"A hundred-plus years ago, we were worried about Teamsters being out of work," Mathieu says. Teamsters then drove teams of horses. Union members today include truckers, who might soon compete with driverless vehicles in their own dedicated lanes.

"You can't have congestion-free driving just because you constantly build roads," observes history professor Peter Norton of the University of Virginia. Now, he says, is an excellent time to learn from what has not worked in the past. "It doesn't automatically get safe just because you have state-of-the-art tech."

Historians say we need to stay behind the wheel when it comes to driverless cars, even if that becomes only a figure of speech.

Camila Domonoske contributed to this report.