The car being in a fatal crash does not mean the car was to blame.
By the sounds of it, it wasn't.
The car and a trailer were in collision. Sounds like the Tesler was being overtaken by the towed trailer, and the trailer driver didn't allow for the extra length.
There was a similar accident in 2003 on the M56 in Manchester when a minibus towing a trailer did the same thing and clipped the car it was overtaking. 7 died, but the driver of the car hit crashed into the hard shoulder and survived.
http://news.bbc.co.uk/1/hi/england/manchester/3054867.stm
In this instance, the autonomous car did not take evasive action to prevent being hit. The driver can take control anytime in a Tesler just by taking hold of the wheel, so the human driver failed as well.