If open, this is one of the first places any officer will look if he suspects that you are a drug user. Do not keep any marijuana or paraphernalia in open view in a car. This includes feathered roach clips people like to hand from their rear view mirror. The feathers are noticeable before the car is stopped, and could play a role in the decision to stop you. The clip would be sufficient to provide probable cause to search for illegal contraband.
Some cops like to collect the feathers on their office walls.
When driving, be concerned about the appearance of your eyes, the smell of your breath and the smoke inside your car. Letting an officer suspect you are stoned will give him grounds for an arrest for driving under the influence. While driving, carry drugs in something like a suitcase, briefcase, backpack or sealed carton. The U.S. Supreme Court has ruled a person has the right to the same privacy with the items in a car as he does at home. They cannot be opened without a search warrant, even after arrest.