Reckless driving practices were studied among 139 high school students aged 17-18. A majority of both boys and girls reported driving at high speeds, and a majority of boys reported racing in a car and passing in a no-passing zone. About one-quarter of boys and girls reported driving while intoxicated. Sensation seeking and aggressiveness were found to be related to reckless driving practices. Fifty-nine of the students kept a log of their driving episodes over a 10-day period. Analysis of these data indicated that the participants drove faster when in an angry mood than when in any other mood. Also, they drove faster when alone or with friends than when their parents were present.