Road rage is strikingly common: In a survey of more than 500 people, 90 percent reported that they had either witnessed road rage or were a victim of it during the past year. And in the ’90s, it led to 218 murders and 12,000 injuries over the course of seven years. Firearms and the vehicles themselves were the most commonly used weapons, and the reasons angry drivers used to explain their actions tended to be trivial—arguments over parking spaces, irritation at horn-blowing, and annoyance at slow drivers.