Feds probe a $999 self-driving add-on after three deaths
NHTSA is investigating whether Comma AI's aftermarket driver-assist hardware, and the open-source software it runs, failed to spot stopped cars ahead.
What happened: On September 21, 2026, NHTSA opened a preliminary evaluation into Comma AI's Comma Four, a $999 retrofit device that adds steering and speed-control assistance to more than 300 vehicle models. The probe covers five crashes: two fatal, killing three people, and four others that left eleven people injured, some seriously. Investigators say the vehicles may not have properly detected or reacted to cars stopped or moving slowly in the same lane, one of the most basic jobs a driver-assist system is supposed to handle.
Why it matters: This isn't just a risk for people who bought the device. Anyone sharing a road with one of these vehicles is affected by how well it detects traffic ahead. Comma markets the hardware around hands-free convenience, even though its own safety instructions say drivers must stay alert and ready to take over instantly. When a product's marketing and its safety fine print pull in opposite directions, it's the driver, and everyone around them, who absorbs the gap.
How it works, plainly: Comma Four runs openpilot, open-source software that handles adaptive cruise control and lane centering. Because it's open-source, outside developers can copy and modify it into their own versions, called forks, such as one named Sunnypilot. A Tesla Model Y was reportedly filmed driving with Comma Four running Sunnypilot instead of Tesla's own system, because the owner's Tesla subscription had lapsed. That flexibility means investigators, and later insurers, may struggle to pin down exactly which software build was steering a car at the moment it crashed.
The rollout: A preliminary evaluation is a fact-finding step, not a finding that the hardware caused the deaths. NHTSA says it will verify each vehicle's system status, test how well the hardware and software handled the crash scenarios, and check whether modified code played a role. Possible outcomes include requirements to log and disclose exact software versions after a crash, tighter marketing rules, and new limits on which modifications are allowed on hardware that controls steering and braking on public roads.