Car crashes kill more teens each year than any other cause; and of the crashes in which they are involved, teens are overwhelmingly at fault. Decades of law-reform efforts have led to mandatory seatbelt laws, an increased legal drinking age, and graduated-licensing systems. Yet traffic fatalities still account for nearly 40% of all deaths of 16- to 19-year-olds. Driving, then, is arguably the greatest public health threat facing U.S. teens. (The next three leading causes of teen death — homicides, suicides, and cancer-related illness — trail only distantly.) While existing measures have had some positive effects, they insufficiently safeguard both young drivers and the public at large from young drivers’ immaturity and inexperience. A report of a National Academies interdisciplinary workshop, for example, concluded that “the sheer magnitude of the injuries and fatalities that continue to result from teen crashes shows that current prevention efforts are inadequate.”
Most of us know that teens crash at rates far higher than those of older drivers. Fewer may be aware that the younger the teen driver, the higher the risk — by far the highest crash rates are those of 16-year-olds (250% higher than those of 18-year-olds), followed by those of 17-year-olds (50% higher than those of 18-year-olds). Driving inexperience and developmental immaturity are the primary factors that contribute to adolescent crash risk. Driving inexperience, however, is not the primary cause of the higher crash risk of younger teens. At younger ages (15 to 17), driving inexperience is secondary to developmental immaturity; not until later ages do different levels of driving experience account for more of the differences in crash rates. Thus the crash risk for 15-year-old beginners is much higher than that for 17-year-old beginners, but the crash risk for 18-year-old beginners is only slightly higher than that for 20-year-old beginners. At each month of driving experience, young drivers crash at rates higher than those of older drivers with equal driving experience.
By ages 15 or 16, adolescents indeed have the cognitive ability required to learn traffic rules and basic driving skills. But the self-regulatory capacities and psychosocial maturity essential to competent and safe driving remain immature in adolescence (the developmental stage between childhood and adulthood, generally spanning ages 12 to 17), as observed in research of adolescent behavior generally and driving behavior specifically, and supported by research of the adolescent brain. When decision-making contexts involve stressors that require the exercise of psychosocial maturity/regulatory competence — requiring, for example, that a decision be made in an unfamiliar situation (such as the new perceptual situations involved in driving); under time pressure (such as the nearly-instantaneous reactions often required when reacting to driving hazards); in in the presence/under the influence of peers (including the direct or perceived influence of peer passengers); or in an emotionally-charged situation — adolescent decision making suffers. These characteristics all confound the execution of whatever nascent driving competence adolescents do possess.