A recent study, which was published in last week's Journal of the American Medical Association, offers a picture of how dangerous it is to get a lift from a teenage driver. Indeed, a 16-year-old driver with three or more passengers has three times the possibility of a serious accident, compared with a teenager driving alone. The authors also found that the death rates for teenage drivers increased greatly after 10 p.m., and especially after midnight. With passengers in the car, the driver was even more likely to die in a late-night accident. Robert Foss, a scientist at the University of North Carolina Highway Safety Research Center, says the higher death rates for teenage drivers have less to do with "really stupid behavior" than with just a lack of driving experience. "The basic issue is that adults who are responsible for giving out licenses fail to recognize how complex and skilled driving is." he says. Both he and the author of the study believe that the way to mitigate   the problem is to have states set up so-called graduated licensing systems, in which getting a license is a process with several stages. A graduated license requires that a teenager first prove himself able to drive in the presence of an adult, followed by a period of driving with night of passenger restrictions   before graduating to full driving rights. Graduated licensing systems have reduced teenage driver crashes, according to recent studies. According to Robert Foss, the high death rate of teenage drivers is mainly due to   _  .
their frequent driving at night their lack of driving experience their wrong way of driving their driving with passengers