As cannabis legalization spreads across the US, law enforcement faces a growing challenge: detecting cannabis impairment in drivers. While traditional methods like Drug Recognition Experts (DREs) and roadside tests prove insufficient, new technologies like saliva tests and brain scans show promise but are still in their early stages. This article explores the limitations of current methods, the potential of emerging solutions, and the pressing need for a reliable, science-backed tool to address the rising issue of drug-impaired driving.