obstacle avoidance - have you seen the Tesla on autopilot obliterate the rolled over truck?
As a total rat hole aside, this is actually a compromise of the design. I did some research on this a bit ago when my wife's new Ranger almost rear ended the car in front of me when "following" with adaptive cruise control.
In cruise control, my car of the same year will accelerate/decelerate and bring the car to a complete stop when in cruise control. It does this with very high reliability. So, I was surprised when in her truck on the motorway and in adaptive cruise control shut down cruise control just as the traffic in front of me came to a stop, and I had to do an emergency stop.
Why is this? It is the compromise of sensor types and number, computing horsepower in the vehicle, and avoidance algorithm design.
For most cars in cruise control, the computer has to think about other cars - moving objects. Stationary objects like light poles, cars parked by the side of the road, bridge supports, etc are seen but largely ignored when the vehicle is at speed. That is how it can track objects around a bend in the road, but ignore the trees that are straight ahead but not on the road.
Think about how your sensors work for proximity in a parking lot - where it sees and takes into account all stationary objects around it and with greater attention to near distance. It also ignores anything further away than a couple car lengths (compromise, effeciency). The car cant have that level of attention at 80 mph - or else it would be braking and sounding alarms constantly, or would need a huge processor and many more sensors (and types). So, that a lot of that info is on stationery objects filtered out from calculations as speed increases, by and large.
So what happens when an object is directly in front of the car and stationary, (and has always been stationary) at freeway speeds? A design compromise (lack of sufficient type/number of sensors, lack of sufficient computing power - both which can lead to algorithm choices/compromises) may be to ignore that object as not relevant.
Which is why Tesla states that, "Current Autopilot features require active driver supervision and do not make the vehicle autonomous".
