Police officers in San Francisco, California, were caught on video pulling over an autonomous driving taxi and were surprised that it took off on them. Police reportedly pulled over the vehicle because its headlights weren't on.

In the now-viral video, police can be seen pulling over a self-driving Cruise taxi at night. One of the officers approached the vehicle and was visibly surprised when he saw that there wasn't anyone in the vehicle when he attempted to open the driver's door. When the officer walked back to his car, the taxi suddenly drove off but then stopped further down the road.

Bystanders were heard commenting on the video, expressing their shock that there wasn't anyone driving the pulled-over car. Another person commented how "crazy" the situation was and why the police pulled over a driver-less vehicle.

General Motors, through its driverless taxi subsidiary Cruise, launched its driverless cars in San Francisco earlier this year. The company said they had provided law enforcement with a 24/7 contact number for incidents involving their autonomous vehicles.

Cruise said the vehicle that was pulled over had operated as expected and pulled over to the nearest safest location after it had detected the police vehicle following it. Cruise said they had already spoken with the police, and no citation was issued against them. A Cruise spokesperson said they had been closely working with the SFPD since the launch of the autonomous vehicles.

Users on social media were quick to share their opinions on the incident, with some criticizing the company for allowing the vehicle to operate with a defective photocell sensor that automatically turns on its headlights. Others commented that the police should have cited the company for the incident, claiming that the defective vehicle could have caused an accident.

Employees from General Motors and Cruise tested the program for weeks before it was publicly launched. Interim Cruise CEO Kyle Vogt stated in a February blog post that the company is the first to offer driverless taxis in a major U.S. city and that the achievement prompted a $1.35 billion investment from Softbank, which had already invested $900 million.

Under its deal with San Francisco, Cruise is only allowed to use its driverless vehicles from 10 p.m., and the cars are only permitted to drive on a limited number of roadways at speeds up to 60 mph. The vehicles are also restricted from operating during severe weather such as heavy fog or rain.