[…] and considering that holding the wheel is even more important without ADAS, yet manufacturers don't warn drivers to hold the wheel in that situation, it's fair to say that people already know that they are supposed to hold the wheel whether the car tells them to or not.
I don’t actually think that’s a valid argument. In the case without ADAS, drivers know, by definition, that they need to have their hands on the wheel, because otherwise the car can’t steer.
With ADAS, a driver can become accustomed to the car steering for them, and rely on it to a flaw, when it definitely is neither billed as nor reviewed as automatic handsfree steering. Keeping your hands on the wheel is no different from not having your legs up on the dash when you are in cruise control. Sometimes, you may need to brake, or swerve, or steer. Keep your feet and hands in the appropriate places as needed.
The false sense of security that ADAS can provide is why it’s more important to remind people to keep their attention on the road and hands on the wheel. ADAS is a helper, not a replacement.
Also, Lucid is supposed to be monitoring the driver's eyes for attentiveness, and whether or not a driver is holding the wheel has nothing to do with whether or not the driver is paying attention.
I’d be surprised if they don’t eventually switch to this, or add it as an option, but it has its own issues; you may need to adjust the wheel so the camera can see you, potentially, depending on your seating position. Moreover, if it sense that your eyes are straying, I have no doubt it’ll ask you to keep your hands on the wheel.
The driver having their hands on the wheel does not necessarily imply that they’re paying attention; that’s true. But it does necessarily mean that their reaction time is quicker, since the distance between hands and wheel doesn’t exist, so the time delay between “thought” and “action” is significantly faster, and that half second may mean the difference between colliding snd not.
If anything, it makes sense to monitor the driver's hands when ADAS is off, and if the driver is not holding the wheel and doesn't respond to warnings, turn ADAS on.
That’s an interesting idea. I could see it being really jarring for people who don’t expect it, but that might be an idea worth exploring!
It might also make sense to bring the car to a safe stop if possible, unless the driver somehow reacts by moving the wheel or taking some other action.
HA does this; if you don’t respond after repeated warnings to put your hands on the wheel, it will turn on the hazards and initiate an in-lane stop. This is illegal nearly everywhere, but the point is if you’re having a seizure or otherwise unable to respond, it may just save your life by alerting others to the issue.