The US government has launched an investigation into crashes involving Tesla’s Autopilot driverless car technology, after being repeatedly urged to do so by an independent regulator that accused the electric car maker of releasing unproven technology on to public roads.

The National Highway Traffic Safety Administration, part of the US department of transportation, revealed on Monday that it had started a probe into 11 crashes of Tesla’s cars where first responder vehicles were present.

The crashes, which led to 17 injuries and one death, all involved vehicles that had either the cars’ Autopilot or Traffic Aware Cruise Control modes switched on, and occurred at scenes that had visible driver warning markers such as cones and arrows, the agency said.