Johns Hopkins researchers tested 30 adults (25 completers) aged 21-55 who used cannabis infrequently, administering 10 or 25 mg THC edibles alongside alcohol titrated to 0.05% or 0.08% BrAC in a crossover design with simulated driving and field sobriety tests. This peer-reviewed JAMA Network study reveals the interaction is synergistic rather than additive, producing greater lane deviations and slower reactions than either substance alone. The original coverage underplays how edibles' delayed onset masks early impairment spikes when alcohol accelerates absorption, a pattern missed in standard additive models. Real-world parallels appear in a 2022 NIDA-funded review (Hartman et al., Addiction) showing combined use doubles crash odds versus alcohol alone, and a 2021 Transportation Research Board analysis of simulator data confirming field sobriety tests detect cannabis impairment in under 30% of cases. Limitations include the modest sample, exclusive reliance on simulation rather than on-road conditions, and exclusion of chronic users, reducing generalizability. Mixing edible cannabis and alcohol creates a hidden, immediate driving impairment risk that directly threatens personal safety.