Credit: Google

A Google self-driving car has been pulled over by a police officer for driving too slowly. The officer appears to have concluded no law was broken but warned Google about possible safety risks.

According to the Mountain View Police Department in California, the car was traveling at 24 miles per hour in a 35 miles per hour zone. An officer pulled over the car after spotting traffic backing up behind it.

The officer then “made contact with the operators.” Though neither the police nor Google have detailed who was on board, California rules require the cars have a human operator who can take control immediately if needed.

The police say the officer asked how the car was choosing the speed at which to drive. The officer also pointed to a California law that says that “No person shall drive upon a highway at such a slow speed as to impede or block the normal and reasonable movement of traffic, unless the reduced speed is necessary for safe operation, because of a grade, or in compliance with law.”

The police department doesn’t mention any ticket being issued as a result of a possible breach of this law and Google notes that “After 1.2 million miles of autonomous driving (that’s the human equivalent of 90 years of driving experience), we’re proud to say we’ve never been ticketed!”

Back in June Google revealed that its self-driving vehicles have been involved in 12 minor collisions during testing. 11 of these involved a human driver rear-ending the Google car after it slowed or stopped. The other involved a human driver using the Google car with the self-driving mode switched off.