The US National Highway Traffic Safety Administration (NHTSA) is expanding its probe into Tesla's Autopilot feature, examining 830,000 vehicles across all four current model lines. The investigation aims to determine if Autopilot exacerbates human factors or behavioral safety risks by undermining the effectiveness of driver supervision. The NHTSA found that in 16 instances, Autopilot aborted vehicle control less than one second prior to impact, suggesting drivers were not prepared to assume full control. A recall of the Autopilot software may be possible, which could be done wirelessly without requiring vehicles to be brought to dealerships.