The company disclosed a total number of collisions, stating that none have been the self-driving cars' fault.
The Associated Press reported Monday morning that three of the crashes in California in the past few months involved Google cars, based on an anonymous source. Google and Delphi, which was operating the other self-driving car implicated in the report, told AP that the collisions were minor and the fault of the other cars involved.
Later Monday, the director of Google's driverless car program went into more detail on Google's 1.7 million miles worth of self-driving car tests and the collisions in which the cars have been involved.
"If you spend enough time on the road, accidents will happen whether you're in a car or a self-driving car," Chris Urmson wrote in a post on blogging platform Medium. "Over the 6 years since we started the project, we've been involved in 11 minor accidents (light damage, no injuries) during those 1.7 million miles of autonomous and manual driving with our safety drivers behind the wheel, and not once was the self-driving car the cause of the accident,"
Several companies are working on autonomous driving technology, and California has approved the testing of such technology. Rules for actual self-driving cars are still being considered, and the safety of the technology will be important in the debate.
John Simpson of Consumer Watchdog told Mercury News reporter Matt O'Brien that the best way for Google to develop trust is to publicly release the accident reports, which the Department of Motor Vehicles considers confidential.
"Google appears to be keeping a big lid on what's going on," Simpson said. "They should simply put out the reports they filed with the DMV."
Without mentioning the AP report, Urmson said in his post that the collisions Google's self-driving cars have been a part of are no different from the typical fender-benders that happen every day, and that autonomous car manufacturers hope to reduce if not eliminate.
"These experiences (and countless others) have only reinforced for us the challenges we all face on our roads today," the Google executive wrote. "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 -- and we'll continue to work hard on developing a self-driving car that can shoulder this burden for us."
Google shares declined 0.5 percent to $535.70 Monday.
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