The technology behind the Tesla crash, explained

The crash that killed a Tesla driver in Florida when his car struck a tractor-trailer may mark the world's first fatal accident in which a computer was at the wheel. The crash occurred when the truck turned left across the 2015 Model S Tesla's path and the car's autopilot failed to slow down. The deadly accident, which took the life of 40-year-old Joshua David Brown of Ohio and is the subject of a federal safety investigation that Tesla disclosed Thursday, is bound to raise a lot of questions about vehicle automation and the future of car travel. It may be tempting to describe this as a driverless car crash, but don't give in. There's a big difference between assisted driving technologies and full automation, and what we have here is the former. We'll get into that below, but let's start first with the nuts and bolts of the autopilot technology at the center of the crash.