Motor vehicle crashes are the leading cause of teen fatalities. A Teen Driver Support System (TDSS) was developed by the ITS Institute that can allow parents to accurately monitor their teen's driving behavior in relation to known risk factors and Graduated Driver Licensing (GDL) provisions. The TDSS, based on a teen's smart phone, provides real-time, contextual in-vehicle feedback to the teen about his or her driving behavior and helps parents monitor certain known risk factors. The system does not allow incoming or outgoing phone calls (except 911) or texting while driving. Feedback to the teen driver includes visual and auditory warnings about speeding, excessive maneuvers (e.g., hard braking, cornering), and stop sign violations. The TDSS prototype also monitors seat belt use and detects the presence of passengers (e.g., based on GDL provisions), two known factors that increase the risk of fatalities among teen drivers. The TDSS can also be programmed to monitor driving during the GDL curfew or a curfew set by parents. A usability review of the prototype TDSS using 30 parent-teen dyads from Washington Country, MN, found that teens and parents held favorable opinions about most of the TDSS functions. Teens and parents both felt that use of the system early in licensure may result in the adoption of safer driving habits even after the system is removed from the vehicle. Several recommendations to improve the system's usability are made based on the results.