The National Highway Traffic Safety Administration announced that it is opening a formal investigation into Tesla’s ($TSLA@US) autopilot function. This comes after a series of crashes involving emergency vehicles. The investigation cites 11 crashes since 2018 in which Tesla vehicles struck first responders who had used flashing lights or other emergency signals. The agency said it would be probing the technologies and methods that Tesla is currently operating in its autopilot functions. Tesla’s stock was trading down around 3 Monday morning.