Donald Redelmeier is riding shotgun in my Chrysler Sebring rental car as I cruise down a four-lane stretch of Bayview Avenue in north Toronto. About 30 feet ahead, a white van slows down to make a left turn. Normally, I wouldn’t think twice about swerving around it. Then again, normally I wouldn’t be sitting beside a scientist who is an expert on the risks of changing lanes. “This is a great lane. Just stay in this lane,” Redelmeier says, in his best driving-instructor’s voice, craning his neck to check the side mirror. “I don’t preach absolute abstinence,” he adds, “but I really resist small temptations.”
Redelmeier, a clinical epidemiologist at the University of Toronto, divides his time between treating accident traumas and figuring out what causes them. Car crashes, he points out, will kill roughly the same number of people worldwide this year as malaria: more than a million. In recent years, he and Stanford statistician Robert Tibshirani have conducted a number of studies on the statistical factors that contribute to this epidemic. They’ve shown that using a cell phone while driving poses the same relative risk as driving with a blood-alcohol level at the legal limit. They’ve demonstrated that drivers are about 35 percent less likely than usual to die in an accident in the month after receiving a traffic ticket, and that driving fatalities increase immediately following the Super Bowl—68 percent in the losing team’s state but only 6 percent in the winning team’s state. Redelmeier has an uncanny knack for using simple statistics to turn up unexpected results. A few years ago he discovered that the average Academy Award winner lives four years longer than other actors and that patients admitted to a hospital over the weekend are 28 percent more likely to die than those admitted on weekdays.
