In the long run I don't think torque sensing is the way to go, no matter how well it's tuned to the driver. There are scenarios where it just won't work well. Have it too sensitive, it'll be easy to trick and it will give false positives, on the other hand if it needs too much input, it'll just defeat the purpose of AP with the driver having to nudge the wheel all the time, even on long straight highway sections where AP should prove most helpful.
I also think a driver facing camera with a good recognition software is the way to go. That for sure will be able to tell if the driver is paying attention, it would be able to see the angle of the eyes, head position, blink rate, etc. It could tell if the driver is reclined too far or if from his position he can or cannot see the road. Really not hard to do, there are already eye trackers out in the gaming world and they can show exactly where the user is looking.
Maybe the camera together with some capacitive sensors in the wheel would be a good combo... but then people will start tying bacon strips to the wheel
I also think a driver facing camera with a good recognition software is the way to go. That for sure will be able to tell if the driver is paying attention, it would be able to see the angle of the eyes, head position, blink rate, etc. It could tell if the driver is reclined too far or if from his position he can or cannot see the road. Really not hard to do, there are already eye trackers out in the gaming world and they can show exactly where the user is looking.
Maybe the camera together with some capacitive sensors in the wheel would be a good combo... but then people will start tying bacon strips to the wheel