Mobile phone distracted driving has been identified as a significant contributor to road trauma. The use of voluntary smartphone applications (or mobile phone functions) which are designed to prevent certain phone behaviours while driving is an emerging countermeasure for distracted driving. Despite the potential for voluntary smartphone applications to reduce crashes associated with mobile phone distracted driving, there has been limited research assessing how effective these applications are in reducing mobile phone use while driving, and the perceived acceptance of such applications. The overall aim of this study is to investigate factors that influence the use of voluntary smartphone applications to reduce the distraction associated with mobile phone use while driving. A total of 712 drivers from Australia participated in an online questionnaire about their preferences and opinions regarding smartphone applications to prevent mobile phone distracted driving. Statistical analyses including a random-effects logistic regression model were conducted to analyse the impact of the application functions on the participants’ willingness to install and activate the application. The willingness of participants to install and activate a mobile phone app was determined by the facility to disable visual-manual tasks and notifications and allow hands-free conversations. The facility to set up automatic responses to inform contacts that they are driving was also important. Females were significantly more likely to install and activate the app. Preferred functions included the blocking of visual-manual interactions such as texting and browsing but allowing applications that support driving such as GPS and Bluetooth. Participants also wanted to retain the ability to use music-playing functions. The ability to give commands to the phone exclusively through audio using a hands-free device or Bluetooth was also favoured. Some age-related differences were evident when examining preferred functions. Overall, findings suggest that the use of app-based technology is a potential intervention opportunity to reduce exposure to high-risk behaviours among motorists and particularly young drivers.@en