New data from the Center for Disease Control and Prevention (CDC) shows that the number of teens who drink and drive has dropped by 54% since 1991. The study examines self-reports of drinking behavior reported to Youth Risk Behavior Surveys. The study also looked at data from blood alcohol levels from teens involved in fatal crashes.The report shows that only 10.3% of high school aged students 16 or older reported drinking and driving in the previous 30 days in 2010. This is a significant drop compared to the 22.3% who reported drinking and driving in the previous 30 days in 1991.The CDC credits the drop in drunk driving among teens to the stricter zero-tolerance laws and to the raising of the legal drinking age to 21. CDC Director Thomas Frieden believes that drinking and driving is not as socially acceptable now. He said, “There is a broader recognition that drinking and driving is not O.K.,” he said.However, car crashes remain the leading cause of death among teenagers in the United States. Dr. Ruth Shults is an epidemiologist at the National Center for Injury Prevention and Control who worked with the study. She said that 1 in 5 teens who were involved in a fatal crash in 2010 had alcohol in their system.