...So what I'm having trouble grasping, is if you have to maintain this same level of alertness ("hands on the steering wheel AT ALL TIMEs *and* eyes on the road just like you were manually driving,"), how is the drive any less fatiguing? I think it was discussed earlier, if I'm constantly wondering if the system is going to need assistance, couldn't that be more fatiguing? It would seem to me you'd wait a little before deciding it wasn't acting properly, so then you have to react even faster, due to that lag. That just doesn't sound relaxing to me, but I haven't actually experienced it either.
We share the same question in mind, and eroscott has not answered. Not being a Tesla owner, but just from reading his posts, I venture the following theory.
When he said repeatedly that the drive is now more relaxed, then it is true. Is he complacent and just lucky that nothing happened? No, he is attentive and from what he wrote, he did catch a few mishaps and correct in time.
So, I think what is going on is that by being attentive, a conscientious Tesla owner experiences the scenarios that may cause trouble, such as construction zones, mismarked lanes, etc... and gets prepared the next time he encounters the same, and it is no longer a big deal. That apparently works, although it seems risky to me. I guess I will always be afraid that I may encounter something new and do not correct in time.
Maybe the car departure from the lane is not so violent, and that it is not too different than when you get blown by a sudden gust of wind, and I have experienced that quite often. You just have to be driving and not sleeping. And that is what he wrote twice.
Then, why is it more relaxed? Apparently monitoring the car and only half-driving is a lot less intense than full-driving.
Should I go out to get one to try for myself?
I tried to make the connection to (regular) cruise control - and I do find that more relaxing. So why? OK, for one, I have confidence in it (it's not complex, I have lots of experience with it), so I can rely on it to keep me from inadvertently speeding, if my attention is on other things, sometimes I may not realize I've sped up by another 10 mph. It allows me to move my feet and leg around a little, which keeps me more relaxed, less fatigued. And defeating it is simple, at the most basic level, hitting the brake like I would do in a 'exciting' situation is the exact same thing I would do anyhow. No delay, no change in thinking. Seems different to me.
-ERD50
I have no problem with cruise control and use it all the time, particularly on my RV which is a beast to keep in the lane. Driving the RV is a full-time job without watching the speedometer all the time. I am not kidding.
I have confidence in the cruise control. Here's why.
1) Cruise control is simple, very little can go wrong.
2) The failure modes are benign. If it is stuck, it cannot maintain speed when I go up hill or down hill. No catastrophe here.
3) Can it go berserk? If it suddenly releases, well it does that when it cannot maintain speed up a steep hill, and that is no big deal (although by the time I stomp on the gas pedal, I have lost a couple more mph in speed, and have a hard time getting it back)
Can it suddenly stomp on the gas? Have never seen it, and if it does, gee, I stomp on my gas pedal all the time to get this RV going when I tow my car.
In cars, the cruise control actuator often has a limited authority, meaning it can only pull the cable so far. And then, it has a slow rate of movement by design.
In short, cruise controls are quite benign. A full authority speed control like in the Tesla is designed to be fast and has full control of a powerful motor, so of course will be more critical.