According to the article, there was a fatal accident between a Tesla Model S and a tractor trailer. This article states that this is the first fatal accident in over 130 million miles. At the time the article was written, the NHTSA had just begun to evaluate what went wrong. According to Elon Musk, the radar was not able to differentiate between the bright sky and the white trailer. Elon Musk also stated that the Autopilot is nothing more than an assistant and that the driver needs to be aware at all times of what is going on. This is because it is new technology that is being tested.
First of all, I just want to say that I am amazed by the fact that Tesla has driven automated cars 130 million miles without a single fatality. That is not to say that there were no other crashes, but it is still impressive nonetheless. I honestly agree with what Elon Musk said. The driver should have been aware that this is still experimental technology and it needs to still be monitored.