The US federal agency in charge of road safety, the National Highway Traffic Safety Administration (NHTSA), has opened an investigation into Tesla’s self-driving Autopilot system. The official investigation follows eleven crashes of Tesla vehicles into first responder emergency vehicles on US roads since 2018.

The NHTSA’s investigation will cover roughly 765,000 vehicles built since 2014. That will include Tesla’s entire current range of models.

The incidents that NHTSA will investigate involve Tesla models crashing into vehicles that are stopped in the road. The agency suspects that Tesla’s Autopilot software cannot handle vehicles that are stopped in the middle of the road. The specific incidents involve emergency vehicles that were stopped in the road to deal with incidents, which Tesla cars then crashed into.

The incidents that will be investigated include a Model S in California which had its Autopilot system engaged which crashed into a parked fire engine that was attending an incident. In another incident in California, a Tesla Sedan with Autopilot engage apparently veered at speed into a police car parked at the side of the road while attending an incident.

Outside the United States, Tesla drivers have reported that their vehicles have veered off the road while Autopilot has been engaged.

The agency will investigate “the technologies and methods used to monitor, assist, and enforce the driver’s engagement”.

This includes Tesla’s Autopilot system and the carmaker’s Traffic Aware Cruise Control. Both systems have been implicated in incidents where Tesla cars have crashed into other vehicles.

Tesla has been criticised for its publicity and claims surrounding its Autopilot system. Critics of the company claim that Tesla suggests in its advertising that its commercially available vehicles are capable of self driving.

Addressing these concerns, the NHTSA said in a statement: “No commercially available motor vehicles today are capable of driving themselves. Every available vehicle requires a human driver to be in control at all times.”