Heather Squires was the designated driver. Never exactly a fun thing, but a college buddy of her husband's was driving up from Tucson to celebrate his acceptance into law school. So when her husband, Jason, asked, Heather said yes. It's not safe to be the designated driver these days, either. At Chuy's in Tempe, Heather's brother and her husband and the soon-to-be-law-school student knocked off four pitchers of beer. Everybody was having a great time. Around 9:30 p.m., they decided to head home. So they piled into Jason Squires' new pickup truck. As planned, Heather drove. They didn't get very...