On a cold winter night a police officer was stalking out a particularly rowdy bar for possible violations of the driving-under-the-influence laws.

At closing time, he saw a guy stumble out of the bar, trip on the
curb and try his keys on five different cars before he found his car.

Then he sat in the front seat fumbling around with his keys for
several minutes. The man was so drunk that everyone else left the bar and drove off before he had even put the keys in the ignition. Finally, he started his engine and began to pull away.

Chuckling at the pathetic driver, the police officer stopped him, read him his rights, and administered the Breathalyzer test. The results showed a reading of 0.0. The puzzled officer demanded to know how this could be.

The driver replied "Tonight I am the designated decoy."