I guess culpably will be determined by who is deemed to be the driver of the vehicle.
The Tesla software or the person behind the wheel. The latter has already stated words to the effect that "it happened too fast for him to intervene" Which possibly suggests the vehicle was travelling at very fast speed. Perhaps the speed was not commensurate with the road conditions ???
Learn how to use Autopilot on the Model S, Model X and Model 3.
Do I still need to pay attention while using Autopilot?
Yes. Autopilot is a hands-on driver assistance system that is intended to be used only with a fully attentive driver. It does not turn a Tesla into a self-driving car nor does it make a car autonomous.
Before enabling Autopilot, you must agree to “keep your hands on the steering wheel at all times” and to always “maintain control and responsibility for your car.” Once engaged, if insufficient torque is applied, Autopilot will also deliver an escalating series of visual and audio warnings, reminding you to place your hands on the wheel if insufficient torque is applied. If you repeatedly ignore these warnings, you will be locked out from using Autopilot during that trip.
You can override any of Autopilot’s features at any time by steering, applying the brakes, or using the cruise control stalk to deactivate.
What are the limitations of Autopilot?
Many factors can impact the performance of Autopilot, causing the system to be unable to function as intended. These include, but are not limited to: poor visibility (due to heavy rain, snow, fog, etc.), bright light (due to oncoming headlights, direct sunlight, etc.), mud, ice, snow, interference or obstruction by objects mounted onto the vehicle (such as a bike rack), obstruction caused by applying excessive paint or adhesive products (such as wraps, stickers, rubber coating, etc.) onto the vehicle; narrow, high curvature or winding roads, a damaged or misaligned bumper, interference from other equipment that generates ultrasonic waves, extremely hot or cold temperatures.
To ensure the Autopilot hardware can provide information that is as accurate as possible, keep the cameras and sensors clean and free of obstructions or damage. Occasionally remove any buildup of dirt by wiping the cameras and sensors with a soft cloth dampened with warm water.
Probably the most concerning part of that video, was the apparent inability of the "autopilot" software to react early enough to the human being that was trying to warn of the danger ahead, sure the braking system did operate, but far too late to avoid the collision, lucky though that the truck was apparently carrying packages that cushioned the impact somewhat. As far as speed, it seems to be on a multi lane highway with other vehicles travelling at similar speeds. Had the Tesla autopilot reacted and avoided the collision, that would have been a major plus in giving confidence to self driving vehicles on our roads.
Back to the drawing board....?
Looking at video the tesla & SUV in middle lane were about the same speed, 0.06s then SUV spots the truck starts slowing changes to truck lane. The tesla locks brakes 0.09s and again 0.13s as it pass person flagging a truck ahead then more locked brakes before crashing into truck. No deviations suggest that the car was on autopilot and driver wasn't very attentive. The findings will be interesting