At its event to show off the car, Google mixed with people. Along with press, Google invited local community members and disability advocates onto its spacious, secure rooftop. Sergey Brin, the co-founder behind Google's futuristic ventures, made an appearance. He reiterated Urmson's point, arguing that for one target market of the technology — several blind community members were given lifts in the car — steering wheels aren't the issue. "That doesn't address the mission of access," Brin said.  Google's announcement comes on the tail of sharp criticism. On Monday, the Associated Press reported that Google's Lexus vehicles were involved in three accidents since September, when California required autonomous vehicle testers to declare a permit.  Read More5 things to knowabout Google's self-driving cars  Later that day, Google released (incidentally, by Google's telling) the first glimpse at numbers on its self-driving car experiment: 11 accidents during the 1.7 million miles on the road since 2009. (That puts its incident rate at more than twice the national average of 0.3 damaging incidents per 100,000 miles.) Urmson detailed the accidents: Seven came from other cars rear-ending theirs, two were freeway side-swipes and one was a silly error from a Google test driver who was using the manual controls at the time. Google insists that the higher rate comes from thorough reporting, something most human drivers ignore.  When its homemade cars hit the pavement, Google will also launch a website for community feedback on the trials, and will begin posting regulator progress reports, including miles driven, noteworthy trends and incidents.  "It sounds cliche, but safety is issue one, two and three," Brin told the audience.  Google's built-from-scratch car looks similar to its debut a year ago, when Re/code took it for an inaugural spin. It uses the same complex software and hardware — a jury-rigged, advanced network of swirling lasers, cameras and radar — as the existing Lexus fleet.  Read MoreSelf-driving cars linked to motion sickness  Over the last year, the cars have grown considerably smarter and more adept, said Dmitri Dolgov, who leads software for the self-driving cars. They can decipher a trash can from a pedestrian, and even pick up what a pedestrian's hand motions mean.  Gradually, they're also learning to handle unusual traffic situations. In Mountain View, Urmson showed earlier footage of Google's Lexus at an intersection when a renegade cyclist crossed in front, running a red light. As the light turned, a truck to the Lexus' left veered ahead, barely missing the cyclist. Google's SUV saw it and stood still. (One car encountered something rarer still: A wheelchair-bound suburbanite chasing a duck; the car opted to stall.)  If anything, the car errs on the side of caution. At the Google X headquarters, Google offered rides to the select few community members and reporters. During my ride, the car easily handled the planned obstacle course. A gentle slowdown when a Googler suddenly walked in front. A smooth turn when another veered ahead on a bicycle. But when my car turned to face the unexpected gaggle of press surrounding Brin, it jolted to a halt. Then lurched ahead like a nervous 16-year-old. The car is not accustomed to large gatherings of people in open spaces, Dolgov explained.
Google announced that the first autonomous vehicle it has manufactured will begin rolling out on public roads in northern California this summer.