From the CDC: "The leading causes of death for the teenage population remained constant throughout the period 1999-2006: Accidents (unintentional injuries) (48 percent of deaths), homicide (13 percent), suicide (11 percent), cancer (6 percent), and heart disease (3 percent). Motor vehicle accident accounted for almost three quarters (73 percent) of all deaths from unintentional injury (Figure 2)."
If there is anything you are going to helicopter about, driving is a good one.