Silicon Valley police were surprised to find nobody at the wheel of a car they pulled over on Thursday – before realising that it was one of Google’s self-driving vehicles.

A Google self-drive car.

A Google self-drive car. Image by Roman Boed / CC BY 2.0

An officer in Mountain View approached the car because it was driving too slowly around the streets and getting in the way of other drivers. The officer contacted Google, whose response is not known. California law allows driverless vehicles to operate in areas with a 35mph maximum speed limit. Read more: