Recently the former Miss USA Rima Fakih was arrested for driving under the influence.
She was allegedly speeding and weaving through traffic with an uncorked, half-empty bottle of champagne and a blood-alcohol level more than twice the legal limit when she was arrested in the Detroit. When the story first broke she has stated that she was driving her friend home because her friend was too drunk to drive and then realized that she herself was too intoxicated to operate a vehicle.
When I first heard this I was concerned. Had they changed the definition of designated driver? Just to be sure I looked it up and sure enough the definition is exactly the same.
The terms "designated driver" and "designated driving" refer to selecting a person to remain sober, as the driver of a vehicle, while others are allowed to drink to excess (with alcoholic beverages). A designated driver is a person who abstains from alcohol on a social occasion in order to drive his/her companions home safely. It is intended as a safe alternative to driving under the influence.
You see Rima before you go out for the evening you are supposed to decide whom among you will remain sober and be the designated driver. The designated driver is not the person that is the least drunk when the bartender yells "last call".