Sweden’s road safety policy, Vision Zero, seeks to eliminate deaths and serious injuries from traffic crashes, and it recognizes that the bottleneck in improving road safety is displacing mobility as the main priority of the road transportation system. This analysis considers the theory and practice of Vision Zero, first interpreting its proposed changes to responsibility for road safety, and then examining how it has been implemented. The research methods include document analyses, field observations, and interviews with Swedish safety practitioners. This study found that Vision Zero’s main innovation is its explicit call for experts to have causal responsibility for injuries. Moreover, Vision Zero expands the responsibility attributed to road users, who are called on to voice demand for safety improvements to civil servants and elected officials. However, Vision Zero also needed to create institutions through which experts could be accountable for their new causal responsibility, and it needed to support popular organizing around traffic injury prevention. I suggest that a major limitation to increasing the status of road safety as a public problem is that it is generally understood as a private problem and changing this perception through policy requires a more deeply engaged public process.