This study was authorized by the California Legislature (Assembly Bill 266, the Medical Marijuana Regulation and Safety Act (73) to help with detection of driving under the influence of cannabis. Healthy volunteers will inhale smoked cannabis with either 0% (placebo), 6.7%, or 12.6% Δ9-THC at the beginning of the day, and then complete driving simulations, iPad-based performance assessments, and bodily fluid draws (e.g., blood, saliva, breath) before the cannabis smoking and hourly over the subsequent 7 hours after cannabis smoking. The purpose is to determine (1) the relationship of the dose of Δ9-THC on driving performance and (2) the duration of driving impairment in terms of hours from initial use, (3) if saliva or expired air can serve as a useful substitute for blood sampling of Δ9-THC in judicial hearings and (4) if testing using an iPad can serve as a useful adjunct to the standardized field sobriety test in identifying acute impairment from cannabis. If interested, please complete the questions below and we contact you to obtain additional information to see if you qualify. If selected for participation in the study, you will be reimbursed for your time and trouble.