The computers at the wheels of Google's self-driving cars appear to be becoming more and more like human drivers.
According to reports released Monday, one caused what is believed to be the first-ever at-fault fender-bender involving one of the cars on a city street in Mountain View, California.
In the accident February 14, Google's 2012 Lexus was driving itself through Mountain View, where the tech giant is headquartered, and when it was forced to navigate around sandbags blocking a storm drain in the right lane, the car ducked left and hit a city bus.
No injuries were reported, but Google's car sustained damage to the fender, wheel and a sensor.
Autonomous vehicle developers operate from the premise that properly programmed, computers can drive better than people. They envision a brave new world in which sensors ease traffic congestion, accidents are a thing of the past and everyone can parallel park like a pro.
As of January, Google was road-testing 22 self-driving Lexus models and 33 prototypes in Mountain View and in Austin, Texas.
Bosch, Delphi, Volkswagen, Mercedes-Benz and Nissan are also testing self-driving cars, according to California Department of Motor Vehicles (DMV) data cited in the Washington Post.
Google said in November that its self-driving cars had been involved in 17 minor accidents in six years in more than 3 million kilometres of driving and had never been at fault in an accident.
The incident with the city bus is the first reported in which a Google autonomous car was at fault in an accident.
The report filed to the department of motor vehicles suggested that the crash could have been prevented with human intervention.
A human test driver traveling in the Google car reported seeing the bus approaching, but believed it would stop or slow to let the self-driving car in and so did not take the controls manually.