As far as i know those AP systems will be nearly completly base on Optical analysis of the road, i saw a developement system that got prity far,.. its able to already make drives on standard Autobahns and there were already live tests in Germany.
If you see the Ap in action its like watching a camera view of the driver with various Head up disp
play like symbols which keep all the signifacant parts marked ,Cars ,middle lines, forward obstakles on your side of the road and the others,..those markers jump arround as situation changes. there are alot of sensors additional to the optical analysis.
lgiht amplification for night drives for example .
And the steering was already running through the standard servo steering.
The monitor engineer just had a laptop on its knees showing the aformentioned picture with a gui showing other data in other windows.. steering wheel moving completly by itself , weired sight.
That test drive,i saw was several 100 kilometrs long.
Its weired seeing somone in mid high traffic sitting besides a empty driver seat at more then 140 Km/h.
I am not sure if i really would want one, on the other hand,.. if you get a stroke and you manage to get to your car you can throw yourself on the back seat and tell the comp go drive me to the hospital.
I wouldnt expect the full blown sytem before 2010 though.