Brain development may play a critical role in whether teenagers are more likely to get into a car crash, a new study suggests.
Motor vehicle crashes are the leading cause of injury and death among 16- to 19-year-olds in the United States.
While previous studies have focused on driving experience and skills, the new study finds that slower growth in the development of working memory is associated with motor vehicle crashes. The finding suggests cognitive development screening may offer a potential new strategy for identifying and tailoring driving interventions for teens at high risk for crashes.
The researchers examined data from 118 youth in Philadelphia who were part of a larger group that participated in a six-wave survey from when they were 10- to 12-year-olds, in 2005, until they were 18- to 20-year-olds, in 2013-14.
The survey measured working memory development, as well as associated risk-related traits and behaviors. This group later participated in a follow-up survey on driving experience.
“We found that teens who had slower development in working memory were more likely to report being in a crash,” says Elizabeth A. Walshe, a postdoctoral fellow at the University of Pennsylvania Annenberg Public Policy Center and at the Center for Injury Research and Prevention at Children’s Hospital of Philadelphia, as well as lead author of the paper in JAMA Network Open.
Working memory, which develops through adolescence into the 20s, is a frontal lobe process associated with complex, moment-to-moment tasks essential to driving.
“Safe driving involves scanning, monitoring, and updating information about the vehicle and environment while managing multiple subtasks (e.g., adjusting speed, steering, in-vehicle controls) and distractors (e.g., peer passengers and cell phones),” the researchers write in the paper. All of these tasks challenge working memory, especially when a young driver has not yet fully learned to automate many basic driving routines.
Adolescent drivers have the highest rate of crashes, injuries, and mortality. While poor skills and inexperience explain some of the risk shortly after a new driver receives a license, crash risk is inversely related to age during the early years of driving. In other words, among equally new drivers, those who are 17 years old have a higher crash rate than those who are 20 years old, which suggests a possible developmental link.
“Not all young drivers crash,” Walshe says. “So we thought, what is it about those who are crashing? It could be related to variability in working memory development.”
Ready or not?
Prior research has shown a link between lower working memory capacity and reckless and inattentive driving, crashes, and poor performance on simulated driving tasks. For the new study, researchers recruited participants from the Philadelphia Trajectory Study, a broad six-wave study conducted across seven years—when the adolescents were 11-13 years old to 18-20 years old—that measured the change in working memory and other characteristics.
Subsequently, in 2015, 118 young adults, including 84 drivers and 34 non-drivers, took the follow-up survey on driving. Among the drivers, 25 reported having a crash history and 59 reported no crash history.
The drivers who reported crashes and those who didn’t started from about the same point in working memory capacity though the trends diverged from there. The researchers found that the relative growth of working memory was associated with car crashes within three years after starting to drive. Young drivers whose trajectory of working memory growth was less-than-average in the group were more likely to report being in a crash; drivers with greater-than-average growth in working memory were more likely to say they had not been in a crash.
The analysis controlled for other risk-related factors including reckless driving and drug use.
The results have important policy implications, the researchers say. While all 50 states have some type of graduated driver licensing (GDL) program that gradually lifts restrictions for young new drivers, the research suggests that individual assessments of adolescents’ cognitive development may play an important part, too.
“If our findings hold up in larger samples with diverse youth, we will need to start assessing cognitive abilities, such as working memory, to see if some adolescents are less ready for independent driving,” says Daniel Romer, research director of the Annenberg Public Policy Center and a senior fellow at the Center for Injury Research and Prevention at Children’s Hospital of Philadelphia.
“There is considerable variation in working memory development during the teen years, and some teens may not be as ready to drive on their own without additional assistance.”
‘Predictable and preventable’
Flaura K. Winston, founder and scientific director of the Century for Injury Research and Prevention at Children’s Hospital of Philadelphia says enabling teens to become safe drivers is a health concern for physicians.
“This research points to the fact that crashes are predictable and preventable,” she says. “It focuses attention more on the role of the driver and the driver’s clinician. A clinician could identify teens who will be at an increased risk and use ‘precision prevention’ to tailor anticipatory guidance so that young drivers achieve independent mobility in a safe way.”
Precision prevention, Winston says, could provide different types of driver training or a release from driving restrictions at different times based on their development.
Some form of standardized screening or testing during adolescence could determine which teens have slower development of working memory, the researchers say.
“Ideally, we’d be able to offer interventions like driver training or technologies like in-vehicle alert systems to assist new drivers who need it,” Walshe says.
Additional coauthors are from the University of Pennsylvania, Children’s Hospital of Philadelphia, and the University of Oregon.