The NHTSA noted the systems "are not designed to reliably perform in all crash modes, including crossing path collisions. The Autopilot system is an Advanced Driver Assistance System (ADAS) that requires the continual and full attention of the driver to monitor the traffic environment and be prepared to take action to avoid crashes."
Both the NHTSA and Tesla have shared data that shows that the driver did not take control of the vehicle ahead of its collision with the tractor trailer. The agency stated that the Autopilot system does prompt the driver to maintain control of the vehicle and requires they place their hands back on the wheel to continue working. It also reported that the automaker recently updated the system with a "strike out" system that locks drivers out of the feature if they fail to keep their hands on the wheel.
Concerning today's news, a Tesla spokesperson told Engadget, "at Tesla, the safety of our customers comes first, and we appreciate the thoroughness of NHTSA's report and its conclusion."
Tesla's blog post about the fatal collision said that the car may have been confused by the white tractor trailer and bright sky, "neither Autopilot nor the driver noticed the white side of the tractor trailer against a brightly lit sky, so the brake was not applied."
While this is good news for the automaker and systems like Autopilot in other vehicles, the NHTSA did note that, "the agency will monitor the issue and reserves the right to take future action if warranted by the circumstances."