Three crashes involving Teslas last month that killed three people have increased scrutiny of the company’s Autopilot driving system.

This comes just months before Tesla CEO Elon Musk has planned to put fully self-driving cars on the streets.

Tesla has said repeatedly that its Autopilot system is designed only to assist drivers, who must still pay attention and be ready to intervene at all times.

But experts and safety advocates say a string of crashes raises serious questions about whether drivers have become too reliant on Tesla's technology and whether the company does enough to ensure that drivers keep paying attention.