Buzz Kill: State Adoption of DUI Interlock Laws, 2005–11

Most states have adopted significant measures to reduce the incidence of driving under the influence (DUI) but a DUI death occurs about every 53 minutes; a significant portion of these accidents are the result of recidivist DUI drivers. A relatively new and novel way states can reduce DUI deaths from repeat offenders is to require offenders to install an interlock device on their vehicle, but not all states have adopted this measure. We explore whether the Policy Typology and Policy Diffusion Frameworks can help us understand the politics behind why some states have adopted interlock policies while others have not. Employing over‐time data from the American states our results suggest that the adoption of interlock laws is best explained by internal factors to the state and the adoption of interlock laws by neighboring states. In addition, the adoption of interlock laws is a form of incremental policymaking—states with existing DUI laws are more likely to adopt interlock policies. We conclude that interlock policies diffuse in a manner similar to other regulatory policies and that interlock policies should be categorized as protective regulatory policies rather than social regulatory policies.