NTSB investigators have determined that the driver of a Tesla Model 3 manually overrode the Full Self-Driving (Supervised) system by pressing the accelerator pedal to 100 percent in a crash that killed Martha Avila inside her Texas home. The vehicle's speed exceeded 70 mph at impact, according to the NTSB's preliminary findings in case HWY26FH014.

The driver, 44-year-old Michael Butler, told investigators he was completing a DoorDash delivery at the time. According to Butler's account, he enabled FSD while changing music on the Tesla's center touchscreen and then lost consciousness. Authorities found no blood alcohol or drugs in Butler's system, and vehicle data showed the brake pedal was never applied in the final minutes before the crash.

According to the NTSB, the driver's acceleration to 100 percent disabled the FSD system entirely. The vehicle was operating under manual control at the point of impact, not under automated steering or speed regulation.

The broader regulatory picture around this crash is layered. The NHTSA is conducting its own investigation into this specific incident. That probe sits alongside a larger NHTSA investigation into Tesla's self-driving technology, opened in October 2025, which scrutinizes Autopilot and FSD crash reporting. In March 2026, NHTSA escalated that probe to cover 3.2 million Teslas equipped with Full Self-Driving. Two separate NHTSA preliminary evaluations are also in motion: PE25012, opened in October 2025, identifies six Standing General Order reports in which a Tesla with FSD engaged approached an intersection, and PE24031, opened in October 2024, involves a Tesla operating with FSD that fatally struck a pedestrian, with one additional crash in those conditions involving a reported injury. NHTSA Engineering Analysis EA22002 examined 211 crashes resulting in 13 fatal crashes and 14 deaths, and Tesla filed a Defect Information Report in connection with that analysis.

Tesla AI head Ashok Elluswamy stated on X in June that the driver manually overrode self-driving by pressing the accelerator to 100 percent in a residential area, a claim now corroborated by the NTSB's own findings.

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 following the crash. The NTSB states that all aspects of the crash remain under investigation while it determines the probable cause, with the intent of issuing safety recommendations. NHTSA Engineering Analysis EA26002 also references a November 28, 2023 fatal Tesla crash; Tesla began developing a software update on June 28, 2024, the day after submitting the SGO report for that crash.

The NTSB has previously examined the intersection of Level 2 driver assistance and human supervision. A 2024 NTSB report, HIR2602, examined fatal crashes involving vehicles operating in hands-free mode and references prior Tesla L2 crash investigations alongside Ford investigations. That report's framing, focused on the gap between automated system capability and driver attentiveness, is directly relevant here. Butler's account, that he enabled FSD and then lost consciousness while interacting with the center display, places this crash squarely within the failure mode that L2 systems are structurally exposed to: the driver is the fallback, but the driver is also the one most likely to disengage from the driving task entirely.

The accelerator-override mechanic deserves attention. Tesla's FSD system, like other Level 2 implementations, allows the driver to assert manual control at any time by pressing the accelerator. This is a deliberate design choice: in emergency situations, a driver who needs to accelerate to avoid a hazard should not have to fight the automation. But the same override path means that a driver who is impaired, inattentive, or incapacitated can disable the system without any friction. In this case, full accelerator input disabled FSD entirely, and the vehicle continued under manual throttle with no brake input and an unconscious driver until it struck a home at more than 70 mph.

The distinction between "the system failed" and "the system was disabled by the driver" will matter for the litigation, for the NHTSA probes, and for the broader policy debate around Level 2 automation. Both things can be true: the driver overrode FSD, and the design permitted that override to result in an uncontrolled, high-speed collision into an occupied dwelling with no automated intervention afterward. Whether NHTSA or NTSB recommendations will address the override-to-disengagement pathway, or the lack of a driver-state monitoring interlock robust enough to detect incapacitation, is not yet known.

The NTSB investigation remains open. A probable-cause determination and any resulting safety recommendations are pending.