Blondes and Cops...

A blonde, brunette, adn a red head were late for a party. So they got in a car and started driving towards their destination. The brunette is in the drivers seat and asks the red head to look around to see if there is anyone near them. The red head says no, so the brunette speeds up and starts going above and beyond the speed limit. Soon the blonde yells, "Someone's following us!!!" The brunette keeps her eyes on the road, but knowing that the blonde wouldn't be able to tell her if it was a cop or not, asked, "Are the lights on the top of the car on?" The blonde waited a few moments and answered, "On. Off. On. Off. On. Off. On. Off."