Driving while yakking driving a car while talking on a cell phone.
"Officers have their hands full already, and unless the legislature makes the fine higher than the $ 25 proposed in these bills, cops might reasonably conclude that the lawmakers don't think DWY is that big a deal. Why go to a lot of trouble to nail somebody for something so minor? Yet it isn't minor. Though a lot of people have gotten in the habit of dialing and talking, and though most of them haven't had a wreck, that doesn't mean it's safe."
—"Please hang up and drive," Morning Star, February 13, 2001
Raleigh lawyer Rob Holmes thinks there should be a ticket for all those drivers who nearly cause wrecks while talking on cell phones:
'DWY,' he says. 'Driving While Yakking.'
—Joanna Kakissis, "Raleigh studies a ban on driving while calling," The News and Observer, April 29, 2000
Today's abbreviation is a play on the legal term DWI, driving while impaired, and was probably inspired by the most famous of the "driving while X" coinages: DWB, driving while black. This sense of DWY is only about a year old, as you can see from the earliest citation.
Note, too, that there's another form of DWY driving while young or driving while youthful that's a bit older:
I too was approached by an Anne Arundel County officer as if I had an 'arsenal of weapons.' I was repeatedly asked if I possessed any illegal substances. After repeated, unfruitful examinations of my vehicle, I was released to continue my daily routine, but emotionally I was in complete disarray and was confused as to the full intent of our officers of the peace. Despite my treatment, however, I was not DWB (driving while black). I had committed DWY (driving while youthful).
Robert C. Davis III, "Readers' views," The Capital, March 23, 1998