The high prevalence use of mobile phones in Australia has led to concerns about the rates and impact of driver distraction, and how technology can be harnessed as an effective countermeasure. In recent years, mobile phone apps have been designed to act as voluntary ‘workload managers’, which work to prevent distracted driving due to mobile phone use. This study investigates the potential use of voluntary apps through four empirical studies utilising both qualitative and quantitative methods – a driver acceptance assessment study, an expert-based risk assessment study, an online-based case-scenario analysis, and an in-vehicle study. Results demonstrate a general willingness to use voluntary apps to reduce distraction, especially among high-risk drivers who report higher levels of visual-manual interaction with their mobile phones. Despite the general acceptance of voluntary apps, there was still reluctance among participants to give up certain benefits of mobile phones. During the in-vehicle survey, there were self-reported reductions in phone use and decreased mental demand while participants were using the voluntary app. However, participants’ intentions to use the voluntary app were influenced by the features and performance of the apps, such that they showed less intention to use the app if they had a negative user experience. Overall, there is value in promoting the benefits of voluntary app use to prevent driving while distracted by a mobile phone. However, only voluntary apps that function reliably, and provide a satisfactory level of integration with the vehicle and the functions drivers use, should be promoted. This report also proposes standard guidelines and recommendations to ensure users make the best use of voluntary apps, and to encourage the relevant organisations to consider advocacy or incentive-based approaches to encourage use.