The probe also found the company's claim did not match up to reality.

The National Highway Traffic Safety Administration (NHTSA) disclosed on Friday that during its three-year Autopilot safety investigation, which it launched in August 2021, it identified at least 13 Tesla crashes involving one or more death, and many more involving serious injuries, in which “foreseeable driver misuse of the system played an apparent role”, The Guardian reported.

It also found evidence that “Tesla’s weak driver engagement system was not appropriate for Autopilot’s permissive operating capabilities”, which resulted in a “critical safety gap”.

The NHTSA also raised concerns that Tesla’s Autopilot name “may lead drivers to believe that the automation has greater capabilities than it does and invite drivers to overly trust the automation”, The Guardian reported.

The agency also found that the company's autopilot may even discourage drivers from taking manual control of the vehicle compared to other automated driving systems.

NHTSA’s new investigation focuses on the software update Tesla rolled out to fix these issues in December, which prompts drivers with increased warnings and alerts to pay greater attention when using Autopilot and Autosteer, reported The Verge.

Reacting to the development, Senator Edward J. Markey (D-Mass.), member of the Commerce, Science, and Transportation Committee, and Senator Richard Blumenthal (D-Conn.) said in a statement: "Within days of Tesla’s December recall of Autopilot, it became clear the company had not done enough to protect drivers and all road users from the dangers of this unsafe technology."

"That is why, last week, we sent a letter to NHTSA urging the agency to more urgently steer Tesla towards safety. As part of NHTSA’s new query, the agency should require Tesla to restrict its Autopilot feature to the roads it was designed for. We urge the agency to take all necessary actions to prevent these vehicles from endangering lives,” they said.

In August 2021, Senators Markey and Blumenthal sent a letter to the Federal Trade Commission (FTC), calling for it to launch an investigation into Tesla’s advertising of driving automation systems.

In February 2022, Senators Markey and Blumenthal sent a letter to Tesla Co-founder and CEO Elon Musk following numerous reports of dangerous braking flaws in Tesla’s Autopilot and Full Self-Driving systems and amid several federal safety investigations, voicing serious concerns with the implementation of the company’s technology.