PROJECT SUMMARY Motor vehicle collisions (MVCs) are the leading cause of death among teens in the United States. Teen drivers who have committed a traffic violation are at an even higher risk of MVC-related injuries and deaths compared to their counterparts without a traffic violation. While parent engagement interventions are an effective strategy to improve driving safety among teens of all risk profiles, these interventions have not been translated and tested among high- risk teen drivers such as those with a traffic violation. Furthermore, to date, no studies have examined the cost- effectiveness of interventions that promote safe teen driving practices. This proposed study addresses princi- pal gaps in teen driving research by translating an evidence-based universal intervention to a high-risk, yet un- derstudied, population of teen drivers with a traffic violation. This study will test, in a hybrid randomized controlled trial (RCT), the implementation, effectiveness and cost-effectiveness of the new intervention, Steering Teens Safe+ (STS+) that integrates in-vehicle driving feedback technology with parent communication training. Our long- term goal is to inform juvenile traffic courts’ adoption and implementation of evidence-based, cost-effective in- terventions into high-risk driving populations, and reduce MVCs and MVC-related injuries and deaths. Our three specific aims are: Aim 1: Determine if both intervention groups are superior to and more cost-effective than the control group on the outcomes of parent-teen communication, teens’ risky driving behaviors, traffic violation re- cidivism, and MVCs. Aim 2: Examine differences in intervention outcomes and cost-effectiveness by mode of deliv- ery (expert- vs. peer-delivered intervention). Aim 3: Identify the contextual factors associated with adoption and im- plementation of the intervention. We will recruit 290 parent-teen dyads from rural and urban juvenile traffic courts in Ohio following their mandatory court hearing. Each dyad will be comprised of a teen driver (ages 16 to 17) who has committed a moving violation and a parent/legal guardian. Enrolled dyads will be randomly assigned to 1 of 3 study groups: 1) Expert-delivered intervention, 2) Peer-delivered intervention, and 3) Control. Our central hypothesis is that the peer-delivered intervention is non-inferior (i.e., not much worse) to and more cost-effective than the ex- pert-delivered intervention and that both intervention groups are superior to the control. This project is significant because it represents a substantial step forward in national research focused on teen drivers, an area in which implementation research has been underrepresented. This study is innovative because it will recruit high-risk teen drivers through a unique partnership with rural and urban traffic courts, utilize cutting-edge in-vehicle driving feed- back technology, and test the mode of intervention delivery. The findings will facilitate the widespread...