Tesla and its Autopilot feature are set to be investigated by the US government after it was accused of causing almost a dozen crashes involving emergency vehicles.

The National Highway Traffic Safety Administration (NHTSA) said on Monday that it was formally investigating Tesla and its partially automated driving system because it failed to spot emergency vehicles including ambulances.

The agency says it had identified 11 crashes since 2018 in which Teslas using Autopilot have hit vehicles at scenes where first responders used flashing lights, flares, an illuminated arrow board or cones warning of hazards.

The investigation covers Tesla’s entire current model lineup, the Models Y, X, S and 3 from the 2014 through 2021 model years of which there are 765,000 vehicles.

“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.

The agency will also look into “contributing circumstances” to the crashes, which the first crash cited by NHTSA on Monday being from 22 January 2018 in Culver City, California, when a firetruck was hit by a Tesla using Autopilot.