The US government has opened a formal investigation into Tesla’s driver-assistance system known as Autopilot after a series of collisions with parked emergency vehicles. The investigation covers 765,000 vehicles, almost everything that Tesla has sold in the US since the start of the 2014 model year. Of the crashes identified by the National Highway Traffic Safety Administration (NHTSA) as part of the investigation, 17 people were injured and one was killed. NHTSA says it has identified 11 crashes since 2018 in which Teslas on Autopilot or Traffic Aware Cruise Control have hit vehicles at scenes where first responders used flashing lights, flares, an illuminated arrow board or cones warning of hazards. The agency announced the action on Monday in a posting on its website. “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 agency said. The investigation covers Tesla’s entire current model lineup, the Models Y, X, S and 3 from the 2014 through 2021 model years. The National Transportation Safety Board (NTSB), which also has investigated some of the Tesla crashes, has recommended that NHTSA and Tesla limit Autopilot’s use to areas where it can safely operate. The NTSB also recommended that NHTSA require Tesla to have a better system to make sure drivers are paying attention. NHTSA has not taken action on any of the recommendations. The NTSB has no enforcement powers and can only make recommendations to other federal agencies such as NHTSA. Autopilot has frequently been misused by Tesla drivers, who have been caught driving drunk or even riding in the back seat while a car rolled down a California highway. The investigation is the latest in a series launched by NHTSA which has opened at least 30 crash investigations involving Tesla cars that it suspected were linked to Autopilot. One investigation into a 2016 crash cleared Tesla’s Autopilot of any blame. Tesla and other manufacturers warn that drivers using the systems must be ready to intervene at all times. Teslas using the system have crashed into semis crossing in front of them, stopped emergency vehicles and a roadway barrier. A message was left early on Monday seeking comment from Tesla, which has disbanded its media relations office. Earlier this month Tesla tweeted that “a Tesla with Autopilot engaged experienced 0.2 accidents per million miles driven, while the US average was 9x higher”. The crashes into emergency vehicles cited by NHTSA began on 22 January 2018 in Culver City near Los Angeles when a Tesla using Autopilot struck a firetruck that was parked partially in the travel lanes with its lights flashing. Crews were handling another crash at the time. Since then, the agency said there were crashes in Laguna Beach, California; Norwalk, Connecticut; Cloverdale, Indiana; West Bridgewater, Massachusetts; Cochise county, Arizona; Charlotte, North Carolina, Montgomery county, Texas; Lansing, Michigan; and Miami, Florida. “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,” NHTSA said in investigation documents. In addition, the investigation will cover object and event detection by the system, as well as where it is allowed to operate. NHTSA says it will examine “contributing circumstances” to the crashes, as well as similar crashes. An investigation could lead to a recall or other enforcement action by NHTSA. “NHTSA reminds the public that no commercially available motor vehicles today are capable of driving themselves,” the agency said in a statement. “Every available vehicle requires a human driver to be in control at all times, and all state laws hold human drivers responsible for operation of their vehicles.” The agency said it has “robust enforcement tools” to protect the public and investigate potential safety issues, and it will act when it finds evidence “of noncompliance or an unreasonable risk to safety”. In June NHTSA ordered all automakers to report any crashes involving fully autonomous vehicles or partially automated driver assist systems. The measures show the agency has started to take a tougher stance on automated vehicle safety than in the past. It has been reluctant to issue any regulations of the new technology for fear of hampering adoption of the potentially life-saving systems. Shares of Tesla, based in Palo Alto, California, fell nearly 2% before the opening bell.