Millions of miles of testing in San Francisco isn’t the easy choice. But we focused on the hardest challenge first because it’s key to scaling our self-driving service. At the same time, we are validating the safety systems needed to fully operate without a driver at General Motors’ 4,000 acre Milford Proving Grounds. This testing is completely without humans in the vehicle. We have now reached a new level of technical capability, and it’s time to combine these development tracks – complex city driving and fully-driverless testing – and take the next step toward achieving our mission.