By Natalie DeCoste

No electric vehicle has been able to match the popularity of Tesla’s cars. Still, the company is facing serious problems after the U.S. auto safety regulators announced that they had opened a formal safety probe into Tesla Inc’s driver assistance system Autopilot.

The National Highway Traffic Safety Administration (NHTSA) announced on Aug. 16 that the organization identified 11 crashes since early 2018 in which a Tesla vehicle using the company’s driver-assistance system hit one or more vehicles involved in an emergency response situation. These accidents prompted the auto regulators to open a preliminary investigation into the driver-assistance system.

“Most incidents took place after dark, and the crash scenes encountered included scene control measures such as first responder vehicle lights, flares, an illuminated arrow board, and road cones. The involved subject vehicles were all confirmed to have been engaged in either Autopilot or Traffic Aware Cruise Control during the approach to the crashes,” explained the investigation document.

Tesla’s Autopilot is an Advanced Driver Assistance System, or ADAS, which keeps the vehicles at the same speed and maintains lane-centering when engaged within its Operational Design Domain. While the ADAS is engaged, the driver is still responsible for detecting obstacles and maneuvering the vehicle around other vehicles in adverse situations.

From the crashes that have prompted the investigation, NHTSA has reported seventeen injuries and one death as a result. The most recent crash was last month in San Diego.

The investigation covers roughly 765,000 Tesla vehicles that span all available models: the Tesla Model Y, Model X, Model S, and Model 3.

“The investigation will assess the technologies and methods used to monitor, assist, and enforce the driver’s engagement with the dynamic driving task during Autopilot operation. The investigation will additionally assess the OEDR by vehicles when engaged in Autopilot mode, and ODD in which the Autopilot mode is functional. The investigation will also include examination of the contributing circumstances for the confirmed crashes listed below and other similar crashes,” read the investigation document.

The NHTSA began asking automakers in June to begin actively reporting accidents involving their Level 2 ADAS, which includes Autopilot. While the active reporting is new, the NHTSA has sent numerous special crash investigation teams to review a series of Tesla crashes over the years. Investigation teams have visited 30 Tesla crashes involving 10 deaths since 2016, where it is suspected that advanced driver assistance systems were used.

NHTSA reminded drivers in a statement that “no commercially available motor vehicles today are capable of driving themselves … Certain advanced driving assistance features can promote safety by helping drivers avoid crashes and mitigate the severity of crashes that occur, but as with all technologies and equipment on motor vehicles, drivers must use them correctly and responsibly.”

Tesla founder Elon Musk, who has taken sole responsibility for Tesla communications in the U.S., has yet to comment on the new investigation. Musk did reply to tweets on Sunday about improvements coming to Tesla’s Full Self-Driving System that ended up being delayed. The Full Self-Driving System is even more automated than the ADAS under investigation.

The NHTSA has the authority to demand a recall on Tesla vehicles, but first, it must decide to upgrade the current preliminary investigation into an engineering analysis.

The NHTSA is not the first government authority to raise questions about Tesla’s Autopilot. The National Transportation Safety Board (NTSB) has criticized Autopilot for its lack of system safeguards.