TREDS Provides Landmark Research on the Impact of Cannabis Legalization on Public Health and Safety in California

TREDS has released a series of groundbreaking publications examining the public health and safety impact of cannabis legalization in California following the passing of Proposition 64. Funded by the California Department of Cannabis Control, the Impact 64 study provides one of the most comprehensive assessments to date of cannabis use, behavior, and perceptions across the state.

Conducted in collaboration with the UC San Diego Center for Medicinal Cannabis Research and Quester, a market research firm, this multi-year effort combined quantitative and qualitative methods to gather insights from more than 5,000 Californians. Using artificial intelligence–enabled survey tools developed by Quester, researchers captured nuanced perspectives on cannabis use patterns, product sources, guidance on use, perceived risks, and driving-related behaviors.

“This project bridges the gap between legalization policy and lived experience,” said Dr. Linda Hill, TREDS Director. “By combining behavioral data and community voices, we can inform future education, enforcement, and healthcare guidance around cannabis use.”

Key findings highlight how legalization has reshaped patterns of medicinal and recreational use, influenced sources of health information, and revealed significant knowledge gaps regarding cannabis laws, impaired driving, and safe use. The results provide critical guidance for policymakers, health professionals, and safety advocates as California continues to navigate the evolving cannabis landscape.

The project has produced several peer-reviewed publications in 2025 alone, including:

Collectively, these findings provide a critical evidence base for future cannabis education, enforcement, and harm-reduction strategies. This reflects TREDS’ ongoing commitment to advancing public health and roadway safety through research, data, and education.