Yes or No

A blonde and a brunette was driving down the road. When a cop appeared behind them and turned on his lights the brunette asked the blonde, "is that a cop behind us?"

The blonde replied "yep."

The brunette then asked, "does he have his lights on?"

The blonde replied with, "yep.. nope.. yep.. nope.. yep.. nope.. yep.. nope.. yep.."