The investigators propose to conduct 3 related randomized, controlled, parallel group, assessor-blind, superiority trials of 6-week text message interventions vs. SMS vehicle safety self-monitoring in young adult participants with risky vehicle behaviors. A total of 500 adult participants will be enrolled: 300 into Cohort 1 (seat belt); 100 into Cohort 2 (distracted driving); 100 into Cohort 3 (drink driving). Each SMS intervention will be designed to target a single risk behavior. The study is powered to show a difference of 15% in the percentage of subjects reporting seat belt use at week 8. Other cohort trials (i.e. distracted driving, drink driving) and outcomes will be exploratory.
