In-Vehicle Feedback With or Without Parent Communication Training and Teenage Driving Behaviors: A Randomized Clinical Trial.

Importance: Motor vehicle collisions are a leading cause of death among teenagers. Effective strategies to reduce risky driving, especially for teenage drivers cited for traffic violations, are critical yet underdeveloped. Objective: To evaluate the effectiveness of ProjectDRIVE, an in-vehicle and smartphone-based driving feedback intervention combined with parent communication training, in reducing risky driving events and unsafe driving behaviors among teenagers with traffic violations. Design, Setting, and Participants: This 3-arm, parallel randomized clinical trial enrolled 240 parent-teenager dyads, randomized evenly (80 per arm) to the control arm (device installed without feedback), the driving feedback only arm, or the driving feedback plus parent training arm. Enrollment occurred from September 28, 2020, to June 30, 2024, with 6 months of follow-up. Participants included teenagers aged 16 to 17 years with an intermediate license and a moving violation, and their parent or guardian, enrolled from 6 juvenile traffic courts across Ohio. Interventions: Intervention teenagers received real-time, in-vehicle and smartphone-based feedback, as well as biweekly emailed reports. Parents in the driving feedback plus parent training arm accessed their teenager's driving reports, completed virtual communication training, and received an online guide for discussing safe driving. Main Outcomes and Measures: Intent-to-treat analyses assessed intervention effects on the incidence rate of risky driving events per 1000 miles and the proportion of miles driven involving unsafe driving behaviors, measured using telematics. Results: Among 240 parent-teenager dyads (teenager mean [SD] age, 16.7 [0.5] years; 123 female teenagers [51.3%]), teenagers completed 160 095 trips. Compared with control, driving feedback plus parent training significantly reduced risky driving event incidence (adjusted incidence rate ratio [AIRR], 0.68; 97.5% CI, 0.51-0.90) and the proportion of miles driven while speeding (adjusted exponentiated β coefficient, 0.54; 97.5% CI, 0.47-0.68). Driving feedback alone did not significantly reduce risky driving but did reduce miles driven while speeding (adjusted exponentiated β coefficient, 0.64; 97.5% CI, 0.54-0.79). Male teenagers exhibited higher rates of risky driving compared with female teenagers, including hard braking (AIRR, 1.39; 95% CI, 1.11-1.73) and sudden acceleration (AIRR, 2.13; 95% CI, 1.42-3.19), as well as greater proportions of miles driven while speeding. Conclusions and Relevance: Combining driving feedback with parent communication training reduced risky driving among teenagers with traffic violations. Continued parental engagement after licensure, especially after traffic violations, might be key to reinforcing driving safety among teenagers. Trial Registration: ClinicalTrials.gov Identifier: NCT04317664.