I've railed on about the safety issues of autopilot before and how I'm not entirely comfortable with the pace they've developed compared to the considerations of human-machine interfaces and driver attentiveness, particularly given my (moderate) exposure to these sort of problems in other industries. Thus I'm particularly interested in that section of the article.
What I found interesting is that figure 10 shows that as you jack up the independence of the machine, the level of driver distraction accordingly increases. Adaptave Cruise Control (ACC) shows a significantly higher percentage of shorter-duration off-road glances than Limited-Ability Autonomous Driving Systems (LAADS). Additionally, countermeasures help to alleviate some but not all of that increase in distraction. Importantly, this is coupled with the point that the duration in which drivers have to react to most impending is under 3 seconds. This may seem obvious but it's a critical set of data to help objectively demonstrate the risks involved with losing or even reducing alertness.
It goes on to say that Tesla has addressed the risks of mode confusion, distraction, etc. and has implemented solutions to address this unreasonable risk, which they in turn define as abuse that is reasonably forseeable. In this, they're talking about the reasonably forseeable risk of eg: the driver not understanding if they're in autopilot or not. It goes on to mention that Tesla has also changed its driver monitoring strategy to promote driver attention, which I take to mean detecting hands on the steering wheel.
Either way, Telsa's main approach to dealing with driver alertness by testing for hands on the steering wheel. My concern is that this doesn't consider the alertness of the driver to their surroundings, particularly other vehicles that may be approaching them or the process of anticipating hazards (approaching an intersecion where there's a blind corner and adjusting focus to pay more attention to what may come from it, for example). I don't see how Tesla's countermeasures address this.
The physical act of manually driving causes drivers to maintain alertness not only to where they're going, but also the situational alertness of what's around their vehicle. Specifically, it's the process of random actions that requires an taking input, making a decision and executing the appropriate action that maintains this alertness. If the driver isn't having to make those random decisions and take action then their alertness drops. Autopilot, even with hands on the wheel, eliminates much of that random decision-making and reacting.
When you drive, you mentally note the vehicle over your shoulder that is in the lane next to you, and subconsciously consider that they may do something insane. You consider those blind corners as you approach them and that vehicles may spontaneously appear out from them. You see a truck on the road which is approaching a bend and give it a wider berth because its centre throw may cause it to cut the corner into your lane slightly. These are all tasks that you do, that you may not do as well or at all when autopilot is steering, because you are not as engaged with the driving process.
Critically, I don't see how ensuring hands are on the steering wheel causes these alertness tasks to continue as frequently as manual steering. The driver may be in the physical location to quickly take over, but they may not be in the mental location to do so. This is the major issue I have with the rapid autopilot development based on my experience in related areas where maintaining situational alertness proved to be very difficult when the person was engaged with only a limited scope of requirements to prove their conscious presence.
I feel like the report doesn't really drill in to this as much as it needs to. It begins to touch on it around Figure 10 but sort of hand-waves it away saying 'Telsa considered it discharged their responsibility to make sure drivers stay focused by implementing countermeasures', but I believe it's more nuanced than that. It investigates the extent to which Tesla's system is good at ensuring drivers are physically present (that is, their hands aren't on the passenger seat making breakfast) but it doesn't really look at the mental presence that delivers situational alertness.
That mental alertness is the major sticking point for me. I don't really have a solution beyond "drive manually" which isn't reasonable, because this technology is here to stay and will continue to grow, but it's why I've always been bearish about the rapid pace of rollout of these driverless technologies, particuarly when advertised as 'beta'. As I've said before, no amount of disclaimer and 'hey, you should do this' really changes how drivers behave once the equipment is placed in their hands.