Closely following a report on teens’ attitudes about driving published in February in Health and Health Care in Schools, the National Academy of Sciences last month released the findings of a workshop that met last year to discuss ways of preventing teen motor crashes.

The workshop report leaves no doubt that “Driving is dangerous, and especially so for new drivers.”  And since most Americans learn to drive before they become adults, the report concentrates on what it is about adolescent new drivers that makes them especially prone to accidents.

The sobering realities:

• Motor vehicle crashes are the leading cause of mortality and serious morbidity for  young people ages 4 through 34, and rates are highest during new drivers’ first few months of driving on their own. In fact, during their first six months of solo driving, newly licensed drivers are about eight times more likely to be involved in fatal crashes than are more experienced drivers, according to the Insurance Institute for Highway Safety. And even after more than six months licensed to drive alone, teens are two to three times more likely to be in fatal crashes than are the most experienced drivers. “From a public health perspective, motor vehicle crashes are among the most serious problems facing teenagers,” the report concludes.

So what would it take to help teens drive more safely? The report lists five critical elements:

• Acquiring the skills to operate the vehicle and to recognize hazards;
• Knowledge of traffic rules and operating procedures;
• Experience, including sufficient practice;
• Maturity, including a capacity for reasoning, judgment, and decision-making; and
• The environment—safe surroundings in which to learn to drive.

Whether any or all of those elements will be present is complicated by the special nature of adolescence itself, the report notes.

In a chapter called “Characteristics of Adolescents That Can Affect Driving,” researcher Ronald Dahl describes what he calls “the health paradox of adolescence”—it’s the healthiest period of the life span physically, a time when young people are close to their peak in strength, reaction time, immune function, and other health assets. But while they enjoy such excellent health, adolescents have a 200 percent increase in morbidity and mortality from their childhood years, with the primary causes of death and disability related to problems with control of behavior and emotion.

“A complex web of physiological, psychological, and environmental conditions contributes to impulsivity in adolescents and influences both decision-making and regulatory functions that affect driving as well as other adolescent behaviors,” Dahl noted. “Indeed, a hallmark of this stage of life, not only in humans but also in other mammals, is the tendency toward increased risk-taking and novelty-seeking, as well as an increased focus on social context.”

Among the factors that cause risky behavior in adolescents are the onset of puberty, with its increased emotional intensity, and another fact—that cognitive development is not  complete until the early 20s, long after the period in which most young people in America are learning to drive.

“A key difference between adolescent and adult brains is in their capacity to manage multiple tasks at once. The capacity known as executive function, which is the key to judgment, impulse control, planning and organizing, and attention, is situated in the prefrontal cortex, which is still under construction during the teen years. In the absence of stress and distraction, most teens function well, but this regulatory capacity can be easily overwhelmed by strong emotions, multitasking, sleep deprivation, or substance abuse. The particular risks posed to teen drivers by extra passengers, music, cell phones, and other sources of stimulation or distraction begin to make sense when this aspect of teen development is understood.”

 Some other characteristics of adolescence also operate in decisions about driving, the report notes.

• Adolescents, like many adults, tend to have what’s known as “the optimistic bias,” meaning that while they know and understand the hazards of driving, they are overconfident of their ability to control those risks—they overestimate their own driving skills.
• Adolescents are intensely attuned to social interactions with their peers, and driving can play an important role in peer interactions, by allowing them to demonstrate maturity or to enhance status and membership in a group, often by hosting the social event that a group trip can be. “They key point in terms of driving safety is that when driving with peers, teens are undertaking two separate, challenging, and complex tasks: they are keenly attuned to the behavior of and interactions among their peers while also operating the vehicle and attending to road and traffic conditions.”
• Teens differ from adults in their need for sleep and in the factors that keep them from getting as much sleep as they need. The report indicates that adolescents need nine hours of sleep a night but generally get between seven and seven-and-a-half hours, with school bus schedules, academic obligations, social opportunities,  and electronic devices in their bedrooms contributing to loss of sleep. “The effects of sleepiness on driving are striking. Teens are at their sleepiest in the morning, and the rate of fall-asleep crashes for 16-to-25-year-olds confirms this, peaking between 6 and 8 in the morning.”

Strategies to Improve Safety

“The extent to which the characteristics of adolescents and their developmental processes are not adequately taken into account in drivers’ education, licensing, and supervisory practices for young drivers was a persistent theme throughout the workshop,” the report concludes.

Driver education programs first developed in the 1930s were widespread in the United States between the 1940s and 1970s, often with 30 hours of classroom instruction in public high schools, plus six hours of instruction behind the wheel. Those programs did not seem, however, to reduce crashes by beginning drivers, and many state have dropped training as a condition of licensure before age 18. The National Highway Safety Administration (NHTSA) is currently considering new curricula and standards for teachers.

Meanwhile, the report notes, many states have adopted what is known as “graduated driver licensing” or GDL, which typically has three phases—an extended practice stage for teens with learners’ permits, a provisional period during which restrictions on driving are imposed, and then full licensure. GDL depends on parents and law enforcement officials for its effectiveness, the report points out, and even with parental supervision, “supervised practice driving has not yet demonstrated safety effects on its own in the United States,” possibly because parents haven’t been given sufficient guidance on how to make best use of this time. A program called Checkpoints, developed by researchers at the National Institute of Child Health and Human Development, provides a structure in which parents can work with their teens during the first 12 months of driving, but it’s not yet clear whether the program reduces teen crashes.

In particular, the report points out, health care providers aren’t doing their part to provide prevention messages to teens and their parents, an absence that’s particularly notable in light of the fact that counseling by health care providers has had positive effects in other areas, such as reducing smoking. Driving safety isn’t “a prominent topic” during medical students’ training in pediatrics, so even experts in adolescent medicine report that they infrequently give teenagers information  about the risk of having passengers in a car, for example, in their practices.

Whether technology can help to reduce dangerous adolescent driving practices is still unclear, the report notes, though some cars now include devices that make it impossible to start the vehicle if the driver is intoxicated, or devices that report on road conditions ahead, or “driving report cards” that enable parents to know their teens’ driving habits. One area in which technology may help is computer-assisted driver education, which allows novice drivers to practice handling dangerous situations without endangering their lives.

Overall, the report concludes, with respect to adolescent driving and its dangers, “a wealth of information is available that has not been brought to bear on a public health issue of immense proportions.”

The full text of the report, “Preventing Teen Motor Crashes: Contributions from the Behavioral and Social Sciences: Workshop Report” is available in PDF at http://www.iom.edu/CMS/12552/31491/40475.aspx.