When teens are subjected to more stringent requirements for obtaining a driver's license, the rate of fatalities involving 16-year-old drivers goes down, researchers have found.

In particular, graduated driver's licensing programs reduce the incidence of fatal crashes involving 16-year-old drivers by an average of 11 percent, the researchers reported. An examination of the most comprehensive state programs revealed a 20 percent reduction in fatal crashes with 16-year-olds at the wheel.

"Annually, about 1,000 16-year-old drivers are involved in fatal crashes in the United States and traffic injury is the leading cause of death among adolescents," said study co-author Guohua Li, MD, DrPH.

"The effectiveness of graduated driver licensing programs in reducing fatal crashes of novice drivers is very robust across genders and geographic regions. Enhancing the enforcement of graduated driver licensing regulations could prevent more premature deaths," Li added.

Effective Programs

Common components of comprehensive licensing programs adopted by 19 states are as follows:

• a minimum age of 15 1/2 for obtaining a learner permit
• a waiting period of at least 3 months after obtaining a learner permit before applying for an intermediate license
• a minimum of 30 hours of supervised driving
• a minimum age of at least 16 years for obtaining an intermediate state license
• a minimum age of at least 17 years for full licensing
• a nighttime driving restriction, and
• a restriction on carrying passengers.

Results Are Conclusive

"Graduated driver licensing programs are a popular way to reduce the risk of vehicle crashes for novice drivers," said Bloomberg School of Public Health Professor Susan P. Baker, MPH, lead author of the study. "We already knew that the programs reduced crash rates of young drivers, but we didn't know which programs were most effective in reducing risk. After completing our study, it is clear that more comprehensive programs have the greatest effect."

States with five program components had an 18 percent reduction in fatal crashes involving 16-year-old drivers compared to states without graduated driver licensing programs, the researchers reported.

Programs with six or seven components were associated with a 21 percent reduction. There was a 16 percent to 21 percent reduction in fatal crashes when programs included an age requirement, plus a wait of at least three months before teens could apply for their intermediate-stage license, as well as nighttime driving restrictions, and either 30 hours of supervised driving or passenger restrictions.

The authors concluded that the most comprehensive graduated driver licensing programs result in the best reduction of fatal crashes of 16-year-old drivers.

The authors findings were strengthened by examining fatal crashes involving drivers aged 20 to 24, and 25 to 29. They did not observe a reduction in fatal crashes in those two age groups. Graduated driver licensing restrictions primarily affect 16-year-olds, indicating that the changes were not associated with the overall driving environment that would also have influenced older drivers.