Lancashire Road Police say a speeding driver in Leyland, who nearly caused a crash, also tested positive for two illegal substances.
The Vauxhall Zafira caught the attention of police on Heald House Road in Leyland by travelling in excess of the speed limit before nearly colliding with another police vehicle at a roundabout.
The car was then stopped by police and the driver tested positive for cannabis and cocaine on a drug wipe.
The driver was arrested.