Police have confirmed to People that the Hairspray actress tried to pass a sheriff's vehicle and collided with "the right rear quarter panel of the radio car".
The Los Angeles County Sheriff's Department said in a statement: "There was minor paint transfer damage to both vehicles.
"Amanda Bynes was subsequently arrested for driving under the influence and booked at West Hollywood Sheriff's Station."
The incident took place this morning (Friday) at 3am. The 26-year-old was driving a black BMW.
This is the second time in a month Bynes has committed a driving offence. She was pulled over and fined by an officer in March for talking on her cell phone while driving.