Google's self-driving cars have traveled 160,000 miles without incident, but that changed last week when one was behind a five-car collision on Charleston Road.
A Google spokesperson said the robotic Toyota Prius was clearly being driven by a human during the trip when the crash occurred on Friday (Aug. 5).
A witness to the crash named Tiffany Winkelman reportedly said that Google's robotic Toyota Prius rear-ended a second Prius, which then hit the Honda Accord she was riding in, which pushed another Accord into the fifth car, another Prius. A Google spokesperson said he did not know how many cars were involved.
"We regret that a Google driver recently caused a minor accident, and we're grateful that no one was hurt," said a Google spokesperson in an email. "Safety is our top priority. One of our goals is to prevent fender-benders like this one, which occurred while a person was manually driving the car."
The incident came to light when a reader of online blog Jalopnik sent in a photo of the car after the crash. It appears to have occurred behind Mountain View's Costco, near Google headquarters. The car is not shown with any major damage.
Police did not immediately respond to requests for comment.
The self-driving Prius uses special sensors and cameras to navigate roads that have been pre-mapped. The goal of the project is to reduce the number of deaths caused by car accidents and to reduce traffic.
Google engineer Sebastian Thrun calls the setup "the perfect driving mechanism." The cars have driven all over local streets, along Highway 1 from San Francisco to Los Angeles, and even down Lombard Street in San Francisco.
Google claims the Google car was in between tests and that the accident was on a road that had not been mapped previously to allow it to drive autonomously on the street.