New framework for tracking cannabis-impaired driving across America

The Cannabis and Roadway Safety Study (CARSS) Phase 2 represents a major methodological advancement in how researchers track and understand cannabis-impaired driving across the United States. This multi-state project surveyed 2,023 cannabis-using drivers across eight states with different legal cannabis regulations—from prohibition to medical-only to recreational access. The study used innovative techniques including real-time demographic monitoring, AI-assisted qualitative analysis, and sophisticated weighting methods to ensure the data accurately represents current cannabis users in each state, addressing long-standing limitations in existing surveillance systems.

The research framework successfully demonstrated the feasibility of collecting detailed behavioral data on cannabis use patterns, driving habits, impairment beliefs, and public health messaging preferences in a standardized way across diverse regulatory environments. Each state achieved its target sample of approximately 250 respondents through quota sampling aligned with 2020 U.S. Census data, with recruitment fielding adjusted based on state-specific dynamics. The integration of AI-assisted open-text responses across all eight states proved particularly valuable for capturing nuanced information that traditional surveys often miss, providing richer qualitative insights alongside quantitative metrics.

This comprehensive methodological framework establishes a scalable blueprint for ongoing cannabis-impaired driving surveillance and public health research. By accounting for differences in state legal contexts and using responsive, real-time monitoring techniques, CARSS Phase 2 enables more accurate tracking of how cannabis use correlates with driving behaviors and risk perception. These findings will inform evidence-based policy decisions and targeted public health interventions designed to address cannabis-impaired driving, a growing public health concern in states where cannabis access has expanded.