The US National Transportation Safety Board (NTSB) has released preliminary findings supporting Tesla's claim that a driver, rather than its Full Self-Driving (FSD) system, was responsible for a fatal crash in Texas. Michael Butler, 44, had told police FSD was engaged when his Tesla struck a house, killing 76-year-old Martha Avila, but Elon Musk and Tesla disputed this, saying Butler had manually overridden the system. The case matters because it touches on the reliability of Tesla's driver-assistance claims and on how blame is apportioned when crashes occur with such systems active.

NTSB's probe found that although FSD was engaged, electronic data showed Butler had overridden it by pressing the accelerator to 100 percent in a residential area, corroborating Tesla's account. Phone data reportedly showed Butler, working as a DoorDash driver at the time, had searched terms such as "Tesla FSD not aggressive enough" beforehand, and he told police he passed out before the crash. Security footage showed the car travelling straight through an intersection at over 70mph rather than turning as planned, before hitting the house. Butler faces manslaughter charges and a $150,000 bond, and is being sued alongside Tesla by Avila's family, who allege a possible defect causing unintended acceleration; both the NTSB and the National Highway Traffic Safety Administration have ongoing investigations.