I was pretty disappointed to see the driver looking down when he was supposed to be monitoring the car’s operation. With that in mind, I consider this a human failure. This car was not intended to function without human oversight, and this driver wasn’t providing that oversight.
Had this car been deemed safe to operate without human oversight, I’d agree the automating system is completely to blame. In a sense, though, this was a system failure. The human was intended to be an integrated component, and this driver appeared to be disengaged.