From the report
<a href="https:&#x2F;&#x2F;static.googleusercontent.com&#x2F;media&#x2F;www.google.com&#x2F;en&#x2F;&#x2F;selfdrivingcar&#x2F;files&#x2F;reports&#x2F;report-1115.pdf" rel="nofollow">https:&#x2F;&#x2F;static.googleusercontent.com&#x2F;media&#x2F;www.google.com&#x2F;en...</a>:<p>&gt;Miles driven since start of project in 2009: “Autonomous mode” means the software is driving the vehicle, and test drivers are not touching the manual controls. “Manual mode” means the test drivers are driving the car.<p>&gt; Autonomous mode: 1,320,755 miles<p>&gt; Manual mode: 955,771 miles<p>So it seems the cars are self-driving only half of the time! The answer to 1) seems to be driver takes over all the time.