The driverless car of Google is going to be fully automatic. I have read patents about the GDC and I found that the car can really run on autonomous mode.
The car can take control from the driver by gauging the amount of pressure he is applying on various controllers like brake pedals and accelerator or steering.
There are other features of the car also like detecting road weather conditions and pedestrians on road.
I think in future it is going to be Tesla Vs Google. However, Tesla can manufacture its own cars and Google cannot. Tesla has a benefit in this aspect.