While police use of sobriety checkpoints has become increasingly common since the 1980s, legal discomfort, particularly Fourth Amendment concerns, persist. While the SCOTUS concluded in its Sitz decision (1990) that sobriety checkpoints' social benefits outweighed costs on individual liberties, states remain free to preclude their use. Indeed, 11 states have ruled sobriety checkpoints illegal.
Aside from their legal status, empirical questions about sobriety checkpoints' efficacy lurk. In an intriguing new contribution to the emerging empirical literature, Sobriety Checkpoint Laws, Fatal Cars Crashes and Arrests, Lauren Jones (OSU--Public Policy) and C. Blain Morin (OSU--Public Policy) explore the effects of a state removing sobriety checkpoints on fatal car crashes and arrests.
Leveraging data from the Fatality Analysis and Reporting System and Uniform Crime Reports, the authors execute a twoway fixed effects (TWFE), event study analysis. As the paper notes, the twoway fixed effects analysis extends a difference-in-difference specification, where changes in outcomes across pre-treatment and post-treatment time periods are compared, across a treated unit and a control unit. As the abstract (below) makes clear, the paper's key findings include an annual 17 percent increase in fatal crashes and a 25 percent increase in the number of DUI arrests in states that cease using sobriety checkpoints.
“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.”
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