How Do You Pull Over a Self-Driving Car?

A question popped into my head while driving to work one morning: How do you pull over a self-driving car?

I‘ve since put this question to dozens of friends and had an interesting conversation each time. To clarify, we’re talking about a fully autonomous vehicle with no human in a position to quickly take over. Maybe it’s your car and you’re occupied with a conference call or binge-watching a favorite show. While driving along, minding its own robot business, a policeman decides to pull your car over. His reason could be a routine inspection or a life-or-death situation. But there’s no driver to signal to – so how does he do it?

Does he have a device that communicates to the car? Sounds reasonable. But think it through – now someone could have the ability to stop in its tracks any car at any time for any reason. Grumpy this morning? Stop ‘em all. Would you want to live in a world where that’s possible? Mind you, we hand over our lives to technology and other people all the time, whether we’re traveling in an elevator, airplane, or amusement park ride. But it feels different when it’s YOUR vehicle.

One response was basically, “A human can recognize the cop and pull over, so why can’t the car?” I hadn’t thought of that, but I like it. The cars will be trained to recognize roads and obstacles, so why not train them to pull over for waving cops? That’s Driving Academy 101 (for Robots).

Questions like these often beg other questions. That’s what Thought Experiment is about – asking seemingly simple questions about the future, and thinking them through, some of us for the first time. We won’t have all the answers, but once The Future finally arrives, maybe it won’t be such an unfamiliar place. And maybe we will have had a hand in building a piece of that future, inspired by a thought experiment.

Reader comments and suggestions are always welcome. Ideas for future Thought Experiments? Love to hear them. Drop me a line at

Author: whomren

Wayne Homren is a longtime student of the history of science, technology and business who’s always been drawn to the future. As a software professional he worked in artificial intelligence back in the 1980s, before it got cold and then hot again in the current century. He was into the Internet before there were browsers, declaring to others “This will change the world.” He started a blog before the word was invented, and was a product manager for the pioneering search engine Lycos before the word Google became a verb. He built cyber tools for inspecting IPv6 packets long before IPv4 addresses were exhausted, and today is a Data Scientist for the U.S. Department of Defense, where the past, present and future often coexist. He lives in Northern Virginia with his wife and their three children.