The aim of this research is to assess drug effects (Xanax and Norco) on driving performance. Researchers will use the Alertness Memory Profiler (AMP) application to compare results to previous related studies.

This study continues a line of research designed to characterize the effects of common recreationally used prescription and illicit drugs with well known stimulant and sedating effects and their relationship to results from the Alertness Memory Profiler (AMP) that included a set of vigilance and memory tasks.

This study uses EEG, EKG, computerized assessment, blood sampling, and driving simulation.

Individuals recruited will be normal, healthy individuals not currently taking the study drugs. The study will involve five visits, a screening visit as well as four dosing visits. The dosing visits will have a clean (double placebo) and three drugged visits (Xanax and Norco placebo, Xanax placebo and Norco, Xanax and Norco). The screening visit will last about two hours and will include drug and pregnancy testing as well as screening for physical/psychological health. Each of the dosing visits will last approximately five to six hours and will include sleep and food intake surveys, being dosed with study drugs or placebos, AMP assessments, a simulator drive, and wellness surveys. There will also be 4 mL blood sampling before dosing, before driving, and after driving.

Inclusion Criteria:

• Healthy adult men and women, based on medical and psychological evaluation
• Currently valid unrestricted (except for vision correction) US driver's license
• Licensed driver for at least the past two years
• Drove at least 5000 miles in the past year, by self-report
• Live within a 60 mile radius of NADS
• Available for five study sessions, with one being approximately 2 hours and four being approximately 5-6 hours
• Peripheral veins suitable for repeated venipuncture
• Systolic blood pressure within a clinically normal range (120 ± 30 mmHg) and diastolic blood pressure of 80 ± 20 mmHg
• Good command of written and spoken English
• Female subjects with reproductive potential must agree to use (and/or have their partner use) one (1) acceptable method of birth control beginning at the screening visit throughout the study (including intervals between treatment periods/panels) and until 2 weeks after the last dose of study drug in the last treatment period. Acceptable methods of birth control include the following: intrauterine device (IUD-with or without local hormone release), diaphragm, spermicides, cervical cap, contraceptive sponge, oral contraceptives or condoms. Abstinence is an alternative lifestyle and subjects practicing abstinence may be included in the study.

Exclusion Criteria:

• Requires any special equipment to help drive, such as pedal extensions, hand brake or throttle, spinner wheel knobs, or other non-standard equipment
• Presence of any clinically significant illness, as detected by history, physical examination, and/or laboratory tests, that might influence driving performance (e.g., seizures, sleep apnea, narcolepsy, vertigo, chronic fatigue syndrome) or put the subject at increased risk of adverse events (e.g., cardiac arrhythmia, hypertension)
• If female, pregnant or nursing
• Currently taking drugs that are contraindicated for use with study drugs
• Significant history of motion sickness or demonstrates significant simulator sickness during practice drives at screening (SSQ). Subjects must have scores below the following values on the SSQ: Nausea < 21, Oculomotor <32, Disorientation < 15, and Total Score < 32.
• History of any illness that, in the opinion of the study investigator, might confound the results of the study or pose an additional risk to the subject from study participation
• Prior participation in a driver impairment or distraction-related research study conducted at NADS that uses the same base drive