between 2004 and 2013 , number of passenger vehicle drivers aged 16 to 19 involved in u.s. fatal crashes decreased from 5,724 to 2,568 , per 100,000 .
new safety features in cars and graduate licenses are among the reasons for the drop in fatalities .
graduated licenses decrease crash rate in teen drivers by 20 to 40 per cent .
three quarters of high school students aged 16 or older are on the road .