KEVIN TUNNELL HAD heard all the warnings about the dangers of drinking and driving. But none of that applied to him. After all, he could handle his liquor. Despite the fact that he was only seventeen and not legally old enough to drink, he had driven after drinking alcohol many times. In fact, he liked to brag to friends that he drove better when he was drunk. On New Year's Eve, Tunnell went to a party where he celebrated the changing of the calendar by slurping down half a dozen glasses of champagne. Maybe it was seven or eight glasses. Shortly after 1 A.M., he left the party and drove off.

At 1:15, Susan Herzon waved goodbye to her boyfriend after leaving a party at his house and stepped into her Volkswagen. Unlike Tunnell, Herzon was not...