Standardized Field Test for Marijuana Impairment II

Inclusion Criteria: * 18-55 yrs/ old * Current driver's license and history of repeated highway vehicle driving experience (at least 2 years) * Recent, recurrent CNB use and felt high when used * Able to read, speak, and understand English * Able and willing to provide written informed consent, and willing to commit to the study protocol Exclusion Criteria: * Current marijuana tolerance, desire to cut down, or cravings to use during periods of abstinence * New CNB users who have not used at least once during their lifetime. * Positive screen for drug and alcohol (except THC) on test day will result in rescheduling the appointment * Former CNB users who are abstaining * Pregnancy, breastfeeding, and ineffective birth control methods. * History of adverse psychological or medical effects following cannabis use * serious medical, neuro-ophthalmological, or neurological illness (i.e. cancer, seizure disorders, encephalopathy) * History of head trauma with loss of consciousness \> 30 minutes or concussion lasting 30 days. * IQ \<80 on the Wechsler Abbreviated Scale of Intelligence * Inability to comprehend written instructions using the WRAT 4 reading achievement test * Any medical/neurological condition that could compromise neurocognitive performance (i.e. epilepsy, multiple sclerosis, fetal alcohol syndrome) * Uncontrolled, persistent high blood pressure * Anyone deemed unsafe to study personnel for any reason