When a Northern California police officer pulled over a slow moving car Thursday, he wasn't greeted by a driver.

That's because he pulled over one of Google's Autonomous Vehicles.

The Google car was going 24 mph in a 35 mph zone, which caused traffic to back up, according to the Mountain View Police blog.

The officer asked the vehicle's operators how they were choosing speeds and informed them of the congestion.

"Bet humans don’t get pulled over for that too often," the Google Self-Driving Car Project group said on a Google+ post.

Google's self-driving cars are allowed to operate on roadways with speed limits at 35 mph, according to police. California law requires that autonomous vehicles to have a driver in the vehicle with the ability to immediately take control at all times. The company put out a statement on Thursday to explain its cars do not operate over 25 mph for safety reasons.

"We want (our cars) to feel friendly and approachable, rather than zooming scarily through neighborhood streets," the Google Self-Driving Car Project group said.

Google is proud to say that they have never been ticketed to date after 1.2 million miles of autonomous driving. Had the officer decided to issue a citation, Mountain View Police Department spokesman Sgt. Saul Jaeger says the person in the position to be in control of the car would have been ticketed.