There is an increasing consensus among policy makers and academics that Mission-oriented Innovation Policy is needed to tackle the grand societal challenges of our time. However, there is little experience in actually carrying out this new type of policy. In this light, we investigate Sweden's ambitious traffic safety policy known as 'Vision Zero'. We consider this policy as a mission-oriented innovation policy towards a societal challenge, as it started from the articulation of a bold, societal goal (zero traffic deaths), fostered multiple types of innovations (technological infrastructural, regulatory), and involved a variety of actors (public, private and professional organizations). We explain what the Vision Zero policy entails, how stakeholders dealt with 'transformational failures', and what made the policy a success. We end with lessons for the development of new mission-oriented innovation policies to address societal challenges.