Waymo told TechCrunch that they are working on the citations, which can occur for various reasons, such as when the vehicles are waiting for their next customer and briefly park in an illegal zone. They also may sometimes stop in commercial loading zones to drop off customers.

The driverless cars picked up 589 parking tickets in San Francisco and 75 in Los Angeles last year, according to a Washington Post investigation.

Waymo robot taxis in San Francisco are programmed to follow the rules of the road but still got hundreds of tickets for parking violations last year.

Driverless cars racked up nearly 600 parking tickets in San Francisco last year as robot taxis favoured convenience over rules of the road.

San Francisco is a hot spot for Waymo vehicles, which operate without a human driver, but it seems the cars don't always play by the rules.