Initial Testing of a Web-Based Intervention to Reduce Adolescent Driver Inattention: A Randomized Controlled Trial.

Only 61 adolescents were randomized, and the small sample, especially in the two distraction-exposed groups, limited the study's ability to detect differences. A post-hoc analysis estimated that 307 participants would be needed to detect a significant difference in simulator cellphone engagement. The original power calculation was for a two-group design, not the four-group design used. The simulator has no real crash risk, and participants knew they were being monitored, so behavior may not match real driving. Self-reported phone use and passenger numbers may be biased by what participants were willing to report. All participants were from Pennsylvania, recruited mainly through a children's hospital primary care system, and the sample was mostly female and white non-Hispanic.

Do not conclude that a brief web-based program prevents distracted driving. The primary simulator outcome was not significant, and self-reported risky driving increased over six months.