There is technology available that can block mobile phones while driving. The aim of this research was to determine if mobile phone blocking technology is an effective and acceptable method for reducing driver distraction among drivers of corporate fleet vehicles. Two different technologies were assessed: one required software to be installed on mobile phones, while the other technology used software in addition to external Bluetooth hardware that paired with the phones. A sample of 104 study participants who regularly drove a corporate fleet vehicle were recruited through SA Power Networks, a major corporation in South Australia. Each participant experienced one of the two technologies, and their opinions on the technology and phone use while driving were assessed using pre- and post-trial questionnaires. A majority of participants reported that phone blocking was not reliable but a majority nonetheless considered the technology they trialled to be an effective way of preventing phone use while driving. The results of this trial suggest that phone blocking products may provide a useful method of changing mobile phone use behaviour while driving. However, the reliability and usability of the products need to improve to reach higher ratings of user acceptance and approval.