For this to work the technology has to work 100% of the time.
I drive lorries and new ones now must have lane departure warning and advanced emergency braking fitted. However both systems regularly give false warnings.
The lane departure warning senses the lane markings, and warns you if you cross the lines without indicating. This is I guess similar technology to what self drive cars will use.
However it regularly gets confused by old road works, and mastic joint sealants.
No way would I trust it to take control.