Graduated licensing programs (GDL) have been shown to reduce teen fatalities by implementing a structure that allows younger drivers to gain experience in stages before they are allowed full licensure. However, a new study released today shows that while fatalities have decreased for 16-year-old drivers, deaths are higher for 18-year-olds.

The study by researchers in California and North Carolina, published in The Journal of the American Medical Association (JAMA), analyzed fatal crashes from 1986 though 2007 of 16- to 19-year-olds by state to determine the association of GDL programs with teen deaths. The study found that the incidence of fatal crashes increased with age and those states with stronger GDL programs had lower incidences of fatal crashes for 16-year-olds compared with states who didn’t have a program or a weaker one. However, stronger GDL programs were associated with higher fatalities for 18-year-old drivers.

Researchers didn’t come to any specific conclusions for the increase in fatalities for the older teen drivers, but they point to a few possible reasons. During the study, GDL programs only applied to drivers under 18 years of age. This may have resulted in older teens having limited opportunity to drive by themselves and some may have delayed licensing until 18.

Some benefits of GDL programs are to reduce the exposure of new drivers to high-risk driving situations, such as after dark and with young passengers. Plus, they encourage supervised driving, with a parent or other adult onboard. However, these restrictions could also be reasons for the increase in deaths seen in older teens, who consequently have less experience in these riskier situations and may have missed the earlier opportunity to learn without adult supervision. Researchers note this could be a form of “payback” where the limited driving experience by 18 years, due to reduced exposure on the road at younger ages, meant some real-world lessons were learned at an older age.

Currently, GDL programs are implemented in all 50 states, but their strength varies. All have three stages—learners, intermediate, and unrestricted. However, they vary in the ages for each stage, time of supervised driving, and restrictions on unsupervised driving and when restrictions are lifted.

It has been noted by a number of organizations, including the Insurance Institute for Highway Safety (IIHS), that stronger GDL programs will help reduce teen fatalities and overall crash deaths. This study may inspire discussion for the possibility of extending the state programs to older teens in order to continue the learning experience. It certainly underscores the need for continued attention to be given to preparing less-experienced drivers for the road.

To see a list of GDL programs in your state, see the IIHS comparison chart.

For more on teen drivers, see our special section.