There are two buttons on Levandowski's steering wheel, off and on, and after merging into an auto-drive lane, he hits on with his thumb. A dulcet female voice marks the moment by enunciating the words auto driving with textbook precision. And with that, Levandowski has handed off control of his vehicle to software named Google Chauffeur. He takes his feet off the pedals and puts his hands in his lap. The car's computer is now driving him to work. Self-driving cars have been around in one form or another since the 1970s, but three DARPA Grand Challenges, in 2004, 2005, and 2007, jump-started the field. Grand Challenge alumni now populate self-driving laboratories worldwide. It's not just Google that's developing the technology, but also most of the major car manufacturers: Audi, Volkswagen, Toyota, GM, Volvo, BMW, Nissan. Arguably the most important outcome of the DARPA field trials was the development of a robust and reliable laser range finder. It's the all-seeing eye mounted on top of Levandowski's car, and it's used by virtually every other experimental self-driving system ever built.