The Role of Supervised Driving in a Graduated Driver Licensing Program

Overall, the analyses did not find evidence that requiring 30 to 60 hours supervised driving practice results in different crash rates for 16- or 17-year-old drivers. With low parental awareness and little or no licensing agency verification, it is difficult to determine whether teenagers drove the minimum number of supervised hours required by their States. Improvements in communications with parents and novice drivers about supervised driving requirements, guidance to parents about the best techniques to provide supervision, and tracking actual hours and conditions of supervised driving would be beneficial.

http://www.nhtsa.gov/staticfiles/traffic_tech/811598.pdf