Google acknowledged on Monday "some responsibility" in a minor fender-bender crash involving one of its autonomous vehicles earlier this month.

However, in explaining the situation on a street of Mountain View, Northern California, where the technology company is headquartered, Google reasoned that "if our car hadn't moved there wouldn't have been a collision."

The self-driving car, a modified Lexus RX450h, struck the side of a public bus on Feb. 14 while operating on the autonomous mode, resulting in no injuries in the car or on the bus but causing damage to the car's left front fender, front wheel and a driver side sensor.

As Google claimed in November that none of its cars had been the cause of the 17 minor accidents in the six-year-old project, during which about 3.2 million km were logged in autonomous and manual driving, the latest incident seemed to be the first caused by its fleet of self-driving vehicles.

"Our vehicle was driving autonomously ... It then detected sandbags near a storm drain blocking its path, so it needed to come to a stop," the Silicon Valley company said in a written statement. "After waiting for some other vehicles to pass, our vehicle, still in autonomous mode, began angling back toward the center of the lane."

The car was moving at about 3.2 km per hour, and "made contact" with the side of a passing bus traveling at about 24 km per hour.

The Department of Motor Vehicles of California posted an accident report filed on Feb. 23 by Chris Urmson, director of Google's self-driving car project.

Referring to the accident report, the company said "our car had detected the approaching bus, but predicted that it would yield to us because we were ahead of it."

During the accident, the test driver, whose presence is required by state law, watched the bus in the mirror and expected it to slow or stop, therefore did not take over the wheel.

"This type of misunderstanding happens between human drivers on the road every day," Google said.

Google has been pushing authorities for more extensive road tests of self-driving cars and has joined other companies working on similar projects to make case that most of traffic accidents were the results of human errors.

Since the latest crash, the company said it has "reviewed this incident (and thousands of variations on it) in our simulator in detail and made refinements to our software. From now on, our cars will more deeply understand that buses (and other large vehicles) are less likely to yield to us than other types of vehicles."

"We hope to handle situations like this more gracefully in the future," it said. Endi