NHTSA Opens Probe Into Comma AI's Comma Four After Three Deaths

NHTSA opened a preliminary evaluation on September 21, 2026, into Comma AI's $999 Comma Four retrofit after five crashes that killed three people and injured 11 others. Regulators are examining whether the system failed to detect stopped or slow-moving vehicles in the same lane and what role community forks of openpilot, such as Sunnypilot, may have played.

• Probe covers five crashes: three deaths and 11 injuries
• Comma Four costs $999 and fits over 300 vehicle models
• The device runs openpilot and supports community forks
• NHTSA is checking whether it detected stopped vehicles in-lane