Objective Inexperienced, less-skilled driving characterises many newly licensed drivers and contributes to high crash rates. A randomised trial of TeenDrivingPlan (TDP), a new learner driver phase internet-based intervention, demonstrated effectiveness in improving safety relevant, on-road driving behaviour, primarily through greater driving practice diversity. To inform future learner driver interventions, this analysis examined TDP use and its association with practice diversity. Design Posthoc analysis of data from teen/parent dyads (n=107), enrolled early in learner phase and assigned to treatment arm in randomised trial. Methods Inserted software beacons captured TDP use data. Electronic surveys completed by parents and teens assessed diversity of practice driving and TDP usability ratings at 24 weeks (end of study period). Results Most families (84%) used TDP early in the learner period; however, the number of TDP sessions in the first week was three times higher among dyads who achieved greater practice diversity than those with less.