of adolescence. Although adolescence is 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, their overall morbidity and mortality rates increase 200 percent from childhood to late adolescence. Many of the primary causes of death and disability in these years—which include crashes, suicide, substance abuse, and other risky behaviors—are related to problems with control of behavior and emotion.

The reasons why adolescents can have difficulty controlling their emotions and behavior are complex, and a thorough overview of decades of research on adolescent development was beyond the scope of the workshop.¹ Instead, the focus was on identifying key insights that may have particular relevance to the problem of teen crashes and to use these insights as an entry point for exploring possibilities for improving the effectiveness of teen driving safety efforts.

A complex web of physiological, psychological, and environmental conditions contributes to an increase in impulsivity in adolescents and influences both decision making and regulatory functions that affect driving as well as other adolescent behaviors. 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 (Romer, 2003; Lerner and Steinberg, 2004). These characteristics foster the development of independence at the same time that they increase young people’s exposure to risk, and it is important to note that they involve both natural and adaptive processes, even though they can have very negative results.

As might be expected, the onset of puberty plays an important role. As puberty begins, changes in the endocrine system can affect drives, motivation, mood, and emotion. This period is characterized by increased emotional intensity and changes in romantic motivation. It is associated with increases in risk-taking, novelty-seeking, and sensation-seeking, as well as an increased focus on social status. These attributes can have significant