ap photo This 2018 file photo shows Tesla 2018 Model 3 sedans sitting on displaty outside a Tesla showroom in Littleton, Colo. The U.S. government has opened a formal investigation into Tesla’s Autopilot partially automated driving system, saying it has trouble spotting parked emergency vehicles.

DETROIT — The U.S. government has opened a formal investigation into Tesla’s Autopilot partially automated driving system after a series of collisions with parked emergency vehicles.

The investigation covers 765,000 vehicles, almost everything that Tesla has sold in the U.S. since the start of the 2014 model year. Of the crashes identified by the National Highway Traffic Safety Administration as part of the probe, 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 have used flashing lights, flares, an illuminated arrow board or cones warning of hazards. The agency announced the action Monday in a posting on its website.

The probe is another sign that NHTSA under President Joe Biden is taking a tougher stance on automated vehicle safety than under previous administrations. Previously the agency was reluctant to regulate the new technology for fear of hampering adoption of the potentially life-saving systems.

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, which also has investigated some of the Tesla crashes dating to 2016, 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.

“Today’s action by NHTSA is a positive step forward for safety,” NTSB Chair Jennifer L. Homendy said in a statement Monday.