A new patent that was issued to Google yesterday provides an interesting account on how and when its self-driving vehicle will take control from the driver. For example, when the driver is ready to relinquish control to the autonomous driving system or computer, the driver may press a button or pull a lever (similar to activating cruise control.) However, before taking control of the vehicle, the computer will assess the safety of the situation, for example, by identifying the GPS location of the vehicle or detecting whether there are a large number of obstacles in the area. When the computer is ready to take control, a light or indicator is activated and the driver may release his or her hands from the steering wheel.
In order to accomodate for emergencies, this patent provides a number of pressure sensitive controls or devices located at different locations in the vehicle, for example, on portions of the steering wheel and/or brake and acceleration pedals. Thus, in the case of an emergency, a driver may grip the steering wheel in order to activate the pressure sensitive controls and instantly re-obtain control of the vehicle. However, in order to prevent returning control to the driver in every case of contact, the pressure sensitive controls may be calibrated to prevent accidential transferring control to the driver, for instance, in the case of an accidential bump.
The figure below, taken from the issued patent (U.S. Patent No. 9,134,729), shows a driver on his phone while the vehicle is in a self-driving or autonomous mode.