How Driverless Cars Will Work

Cars of Tomorrow. Still not Flying.

HSW 2008

Fine, nerds. We get it. We thought we'd have flying cars, but we don't. You know what we do have? A bunch of cars driving around the greater San Francisco metro area with bizarro contraptions on the roof! That's equally awesome, right?

Maybe it's a little more Batman DIY rather than Superman with powers at birth. But it works. Google has had a fleet of driverless cars since 2009, and they've driven over a half a million miles (804,672 kilometers) without a crash. Human drivers get in an accident about every half a million miles (804,672 kilometers) on average in the United States, so either the Google cars are due, or they're going to out-drive humans yet again.

Several manufacturers have driverless cars in the works, but since Google of all places has the jump on this project, they're also more forthcoming (sort of) about how their cars work. The Chauffeur system, as they call it, uses lidar, which stands for light detection and ranging and is not related to the liger, which is a lion and a tiger. Lidar works like radar and sonar, but it's far more accurate. It maps points in space using 64 rotating laser beams taking more than a million measurements per second to form a 3D model in its computer brain that's accurate to the centimeter. Preloaded maps tell the system where the stationary stuff is -- traffic lights, crosswalks, telephone poles -- and the lidar fills in the landscape with moving objects like people. It also has regular ol' radar, a camera and GPS to help out.

But don't snap that sleep mask over your eyes and lean the driver's seat all the way back just yet, though. Chauffer still needs you to take over sometimes, like pulling out of or into your garage and driveway or negotiating tricky highway interchanges. Not even a robot car can understand left-lane exits.

Google's system isn't necessarily married to the Prius, though those have been the cars used most often during testing so far. That big bracket could be bolted onto any car with the sensors and software to handle it -- and the money. Chauffer's price will have to come down from the $75,000 neighborhood to be adopted by most drivers. Google expects to have it ready and -- fingers crossed -- cheap enough for people to afford by 2018.