One data gap is the lack of information about novice teenage driving risk. Motor vehicle crashes are a leading cause of injury and death among adolescents. The Naturalistic Teenage Driving Study (NTDS) yielded new and important information about teenage driving risk, including factors associated with crash and near crashes and risky driving (Simons-Morton et al., 20lla); Using objective measures of risky driving from data recording devices installed in study participants'vehicles, NTDS confirmed novice teen drivers'elevated crash rates, relative to adults. Specifically, novice teenage drivers have nearly four times the crash/near crash (CNC) rates and nearly five times higher rates of kinematic risky driving (e.g., elevated gravitational force event rates) of adults (parents driving the same vehicles (Simons-Morton et al., 2011b). Also, we found that the likelihood of a CNC was significantly higher for teenage drivers when engaging in secondary tasks such as telephone dialing, texting, eating, and reaching for objects (Klauer et al., under review). However, the NTDS was based on a small sample of 42 teens and 54 adults, hence there is a need to replicate and confirm analyses with larger samples. For example, analyses showing that monthly kinematic risky driving rates predict the likelihood of a CNC In the subsequent month are the sort that are typically verified in subsequent analyses with larger and more diverse samples (Simons-Morton et al., 2012). Also, previous analyses were limited because NTDS teenage driver exposure to certain driving conditions, for example, rain, highways, and teenage passengers, were too limited for stable analyses, but could be done with a larger sample. Two additional naturalistic studies have been conducted with teenage driver samples based on the same technology as the NTDS, with accelerometers, GPS, and cameras, which provide information about elevated g-force event rates, CNC rates, secondary task engagement, and speeding, The first is the NICHD-funded Supervised Practice Driving Study (SPDS) that assessed a sample of 82 teenage and 112 adult drivers. The second Is the Strategic Highway Research Program 2 (SHRP2) study, sponsored by the Transportation Research Board (TRB). SHRP2 assessed samples of drivers in four geographic regions of the US, including <200 16-17, 18-20, 21-25, and 35-45 year olds. The SHRP2 data are publicly available, and provide an unprecedented opportunity to examine teenage driver crash risk. Given the productivity of the NTDS and the experience gained from it, PRB researchers are uniquely positioned to leverage the available naturalistic driving data by combining these three sources of data (NTDS, SPDS, SHRP2) to create a dataset of approximately 324 teenage and 374 adult drivers that would enable definitive analysis of teenage driving risk
