Tesla's Autopilot has won plenty of fans since it was first installed in the Model S, but it's not perfect. The system's relative youth has been brought into sharp focus by an accident being investigated by the NHTSA, where a driver using Autopilot was killed when his Model S hit a white tractor-trailer as it crossed the highway.
In the accident, Joshua Brown's Model S was operating in Autopilot mode when the trailer pulled across the highway. According to Tesla, the combination of a bright sky and white trailer may have made the trailer hard to see, contributing to the accident.
Because the trailer sits much higher than a regular car, the Tesla's roof was ripped off when its windscreen made contact. The car then slid about 100 ft (30 m) before coming to rest.
Following the accident, Tesla was at pains to point out the fact that Autopilot is still a public beta, and drivers are told it is "an assist feature that requires you to keep your hands on the wheel at all times." The system also displays a message telling drivers to "always keep your hands on the wheel. Be prepared to take control at any time" when activated.
The company described Joshua Brown as a "friend to Tesla and the broader EV community, a person who spent his life focused on innovation and the promise of technology and who believed strongly in Tesla's mission."
Autopilot uses an array of sensors and cameras to keep the car between the white lines on the highway. At the front, a radar unit works to maintain a set distance behind the car in front, while a camera reads the lines on the road. All around the car, there are long-range ultrasonic sensors projecting 16 ft (4.8 m) in every direction, building a picture of what's sitting beside and behind the vehicle on the road.
It isn't perfect, though, with drivers needing to pay attention to what's going on in case the car misinterprets the line markings or doesn't react quickly enough to its surroundings.
This is the first reported death of a driver using Tesla's Autopilot.