RecruitingMedical Marijuana and Open Road Driving TaskMedical marijuana use among adults 50 and older has more than doubled in the past decade with exponential increases projected in this demographic by 2050, and prescription opioids are one of the most common treatments for pain management in this population. To date, no studies systematically assess driving performance in a rigorous and ecologically valid manner accounting for long-term medical marijuana use and/or the combined effect of prescription opioid use in adults 50 and older who endorse chronic or severe non-malignant pain. Further, studies examining how older adults self-regulate prescription medication use and driving behavior is limited, with none rigorously examining medical marijuana.