The Safer Driver App Decreases Mobile Phone Induced Distracted Driving: Evidence From a Randomized Controlled Trial

When using a mobile phone while driving, people are more at risk of causing or being in a crash. To address distracted driving behaviours related to mobile phone use, we developed a mobile coaching app, Safer Driver. The app collects data on a person's driving behaviour and implements behavioural change techniques to help people make smart changes to reduce their distracted driving behaviour. Initially 814 participants were randomly assigned to a 30-day trial period of the Safer Driver app (intervention group, n=573) or the control app (control group, n=241). The control app did not provide any coaching and only collected driving behaviour data. We measured the relative distraction duration score as a proximal outcome. Only participants who were assessed as distracted drivers at the start of the trial were included in our main analysis. This resulted in 182 distracted drivers in the intervention condition who interacted with the Safer Driver app and 86 distracted drivers in the control condition. In line with our hypothesis, the relative distraction duration score was significantly lower at the end of the trial period for distracted drivers who received digital coaching via the Safer Driver app, compared to distracted drivers who received the control app. The findings from this trial indicate that digital coaching via a smartphone application has the potential to decrease mobile phone usage while driving. Digital coaching is a promising way of changing people's behaviour towards safer driving habits.