Recently, a police patrol car was parked outside a local bar. After last call, the officer noticed a man leaving the bar so intoxicated that he could barely walk. The man stumbled around the parking lot for a few minutes, with the officer quietly observing the whole time. After what seemed an eternity in which he tried his keys on five different vehicles, the man finally managed to find his pickup truck and fall into it. He sat there in the bed of the truck for a few minutes as a number of other patrons left the bar and drove off.
Finally, he got into the cab and started the engine, switched the wipers on and off (it was a dry summer night), flicked the blinkers on and off a couple of times, honked the horn and then switched on the headlights. He drove the truck forward a few inches, reversed a little and then remained still for a few more minutes as some more of the other patrons' vehicles left. He sat there fiddling with his window for so long, his truck was the only car left in the parking lot. Finally, he pulled out and drove slowly down the road, weaving gently from side to side.
The police officer, having waited patiently all this time, started up his patrol car, put on the flashing lights, promptly pulled the man over and administered a breathalyzer test. To his amazement, the breathalyzer indicated no evidence that the man had consumed any alcohol at all! Dumbfounded, the officer said, "Sir, I'll have to ask you to accompany me to the police station. This breathalyzer equipment must be broken."
"Oh, I seriously doubt it", said the driver. "Tonight I'm the designated decoy."