A man descends in an elevator at the Lloyds Insurance building in London, in 2010.

One of the challenges in describing the potential of self-driving cars is that they promise to do so much. Technologies that save lives, decimate and create entire industries, and uproot long-held perceptions of space and time don’t come around very often.

Which is part of why it can be useful to try to think about driverless cars in the context of technological revolutions of the past. If this moment in technological history is indeed pivotal, which other transformative moment in technological history is it most like?

In the past few months, I’ve posed this question to dozens of engineers, scholars, and executives who are focused on self-driving cars. Three answers came up repeatedly.

The first two answers aren’t all that surprising: The dawn of self-driving cars reminds a lot of people of a time when the original automobiles were in their infancy. Airplanes, too. (“When I rode in the Google car last summer, I felt like I was at Kitty Hawk,” the Massachusetts Institute of Technology engineering professor John Leonard told me, referring to the site of the Wright brothers’ famous airplane test flights in 1903.)

The third response was a bit more unusual.

“Another related technology, in a lot of ways, is the elevator,” said Chris Urmson, the head of Google’s self-driving-car project. “It’s another technology that had a fairly profound impact on cities.”