-- Google's fleet of self-driving cars have traveled more than 1.7 million miles, collecting data about performance and sharing the road with manual drivers.
Along the way, they've also racked up a few dings -- but by no fault of their own, according to the company.
With more than 20 cars in its fleet constantly being tested with safety drivers in the front seat, Google said the cars have been involved in 11 minor accidents resulting in light damage and no injuries.
The self-driving cars are driven a total of 10,000 miles per week, mostly on city streets.
While software and sensors can help the cars take action faster than a human driver, Urmson wrote that "sometimes we won’t be able to overcome the realities of speed and distance; sometimes we’ll get hit just waiting for a light to change."
With 360-degrees of awareness, the self-driving cars are gaining new insights into dangerous driving behaviors, including drifting lanes and red light running -- both of which can contribute to accidents.
"We'll continue to drive thousands of miles so we can all better understand the all too common incidents that cause many of us to dislike day to day driving," Urmson wrote. "And we'll continue to work hard on developing a self-driving car that can shoulder this burden for us."