To protect cyclists on the roads, state governments in Australia have introduced laws that set a minimum space drivers must give cyclists when overtaking them. These laws are now in place nationwide, with Victoria the final state to join the ranks last month. But do these passing distance laws actually change drivers’ behaviour towards cyclists? Our research set out to answer this question by evaluating Western Australia’s passing distance law introduced in 2017. We found that since the law took effect drivers do indeed report giving cyclists more space when overtaking. However, there were possible unintended consequences. Drivers also self-reported more aggressive behaviour directed at cyclists, such as beeping horns or swearing.