The National Highway Transport Safety Administration (NHTSA) has opened a preliminary investigation into potential issues with the Tesla Autopilot system, Automotive News reports. The investigation was opened last Friday, and involves the Tesla Model S, Model 3, Model X and Model Y in model years from 2014 to 2021, according to a NHTSA document. 765,000 vehicles are estimated to be affected, it said.

The Office of Defects Investigation, an agency within the NHTSA said it had identified 11 Autopilot-related crashes in which Tesla vehicles driven near road scenarios where first-responder vehicles were present, and had subsequently collided with one or more vehicles at the scenes, the agency wrote in its report. In addition to the 11 crashes, the report cited 17 injuries and one death, according to the news site.

All Tesla vehicles involved were confirmed to “have been engaged in Autopilot or Traffic-Aware Cruise Control during the approach to the crashes,” it added. “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 report continued.

Safety regulators in the United States will investigate the driver assistance technologies and methods used for the monitoring, assisting an enforcing of the driver’s engagement with the task of driving when Autopilot is in use, as well as how the vehicles identify and respond to vehicles and obstacles on the road, Automotive News wrote.

The NHTSA said in a statement that the preliminary evaluation “starts the agency’s fact-finding mission and allows additional information and data to be collected, in this case about Tesla Autopilot,” it said.

“[The] NHTSA reminds the public that no commercially available motor vehicle today [is] capable of driving themselves. Every available vehicle requires a human driver to be in control at all times, and all state laws hold human drivers responsible for the operation of their vehicles,” it continued.

“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,” an NHTSA spokesperson added.