Federal investigators have determined that the driver of a Tesla Model 3 turned off the car's self-driving system by pressing the gas pedal all the way down, moments before the car crashed into a Texas home at over 70 mph, killing Martha Avila inside.

The driver, 44-year-old Michael Butler, told investigators he was completing a DoorDash delivery at the time. According to Butler, he turned on Tesla's Full Self-Driving feature while changing music on the car's center screen and then lost consciousness. Tests found no alcohol or drugs in his system, and the car's data showed he never touched the brake pedal in the final minutes before the crash.

Here is how the self-driving system works in this Tesla. Tesla's Full Self-Driving, or FSD, is what experts call a "Level 2" system. That means the car can steer and control its speed on its own, but the human driver is supposed to pay attention and take over if anything goes wrong. Think of it like cruise control that can also steer — helpful, but not a replacement for a human driver.

The NTSB (the federal agency that investigates transportation accidents) found that when Butler pressed the accelerator pedal all the way down, that action turned off FSD completely. The car was being driven manually by Butler, not by the self-driving system, at the moment it hit the house.

Tesla designed it this way on purpose. If a driver needs to speed up quickly to avoid danger, they should be able to do so without fighting the car's computer. But the same feature means that a driver who is impaired, distracted, or, as in this case, unconscious, can switch off the self-driving system without any warning or obstacle.

The regulatory picture is complex. The NHTSA (the federal agency that regulates car safety) is conducting its own investigation into this crash. That probe is part of a larger investigation into Tesla's self-driving technology that started in October 2025 and now covers 3.2 million Teslas with Full Self-Driving. Other federal reviews are looking at additional crashes, including one where a Tesla in self-driving mode fatally struck a pedestrian.

Tesla AI head Ashok Elluswamy said on X in June that the driver turned off self-driving by pressing the accelerator in a residential area. The NTSB's findings now confirm that claim.

Martha Avila's family filed a wrongful death lawsuit against Butler and Tesla on June 24, accusing both of negligence. Butler was charged with manslaughter in July.

The NTSB has looked at this kind of problem before. A 2024 report examined fatal crashes involving cars in hands-free mode and focused on the gap between what the technology can do and whether the human driver is actually paying attention. Butler's account — that he turned on self-driving and then passed out while using the car's touchscreen — fits exactly the kind of situation that makes Level 2 systems vulnerable. The driver is supposed to be the backup, but the driver is also the person most likely to stop paying attention.

The difference between "the technology failed" and "the driver turned off the technology" will matter for the lawsuits and for future regulation. Both can be true at the same time: the driver overrode the self-driving system, and the car's design allowed that override to end in a high-speed crash into an occupied home with no automatic intervention afterward.

The NTSB investigation remains open. A final determination of the cause and any safety recommendations are still to come.