Sobriety Checkpoint Laws, Fatal Car Crashes and Arrests

Sobriety checkpoints have been used since the early 1980s to enforce laws prohibiting driving while intoxicated (DWI), and to deter DWI. However, their constitutionality has been questioned, as they allow police to stop drivers without cause. As a result, eleven states have banned their use. Using a two-way fixed effects event study analysis, we estimate the effect of rendering sobriety checkpoints illegal on state-level counts of fatal car crashes, and arrests for driving under the influence of drugs or alcohol (DUI), and drug possession. We find evidence that when states make sobriety checkpoints illegal, the number of annual fatal crashes increases by 17 percent. We also find evidence that rendering sobriety checkpoints illegal leads to a 25 percent increase in the number of annual DUI arrests in a state, suggesting that the deterrent effect of checkpoints is much stronger than their enforcement impacts. We also find suggestive evidence that eliminating sobriety checkpoints increases racial disparities in DUI and cannabis possession arrests, with larger impacts on arrests among Black residents.