TEENAGE DRIVER CRASHES -- CARRYING PASSENGERS AS A RISK FACTOR Li-Hui Chen, MS, Ph.D. Assistant Scientist Johns Hopkins School of Public Health Center for Injury Research & Policy

Readings Carrying passengers as a risk factor for crashes fatal to 16- and 17-year-old driversCarrying passengers as a risk factor for crashes fatal to 16- and 17-year-old drivers Reducing fatal crash risk among teenaged driversReducing fatal crash risk among teenaged drivers Graduated licensing: a blueprint for North AmericaGraduated licensing: a blueprint for North America

Learning Objectives: Understand the scope of MV injury for teenage drivers Learn about the risk to teenage drivers of carrying passengers Learn about the GDL system

Performance Goals: Be able to describe the importance of MV injury for teenagers Be able to describe the risk of carrying passengers for teen driver Be able to describe the ideal GDL system

Background For U.S. teens, MV crashes are the leading cause of death, accounting for 36% of all deaths have a much higher rate than for older drivers

Background --Haddon Matrix Phases Factors HumanVehicleEnvironment Precrash Carrying Passengers Crash Postcrash

Background —GDL System Lets teen drivers earn experience step by step and in a less risky environment

Background --Central framework for GDL Three stages Supervised learner’s period Intermediate license Full license

Background —Current GDL adoption in the U.S.Current GDL adoption in the U.S. 30 states had adopted full graduated licensing systems 14 states had some passenger restrictions

Methods --Data FARS: All fatal crashes in the U.S.FARS GES: Sample of police reported crashes in the U.S.GES NPTS: Survey of travel patterns in the U.S.NPTS

Methods --Analysis Risk of death per 10 million trips Risk of death per 1000 crashes Relative risk and confidence intervals

Results

Trip-Based Risks for Teenaged Driver Deaths 6AM-9:59 PM10-11:59 PM12-5:59 AM Passenger Present NoYesNoYesNoYes DR RR

Results Driver Deaths (aged 16-17) per 1,000 Crashes Age and Number of Passengers Aged 13-19Aged None1>=21 DR RR

Results Teenaged Driver Deaths per 1,000 Crashes Sex and Number of Passengers FemaleMale None1>=21 Both Sex DR RR

Results -Summary Fatal crash rates for drivers aged increased with the number of passengers for both day and night Crashes are more likely to be fatal in the presence of male, teen, and age passengers

Discussion--P ossible explanations Dangerous driving behaviors Distraction Alcohol involvement

Discussion --Limitations Unable to control alcohol Do not have information on age of passengers in travel pattern

Conclusions Restrictions on carrying passengers should be considered for inclusion in graduated licensing systems for young drivers

Further Studies Age of passengers The relationship to alcohol use Why carrying passengers increases risk