The media has widely reported that cell phone use impairs driving ability as much as a blood alcohol of 0.08.
Of course the media reports don't give us enough data to make any decisions on, thus my slightly tongue-in-cheak posting title. It's noteworthy that other studies suggest a conversation in the car may be equally distracting. I find my kids to be far more distracting than phones, passengers, alcohol or incoming meteors, but our situation is perhaps atypical.
If I were to be daring, however, I'd wager we'll discover that the subjects they're doing these tests on (grad students?) probably drive as well when intoxicated, under test conditions, as does the average healthy 75 yo in late afternoon.