What is the law on driving under the influence (DUI)? Colorado is an "expressed consent" state and you agree to not drive with excessive alcohol in your system as a condition of your driving privilege. You agree to undergo testing for alcohol if the police officer has reasonable cause to suspect you of drunk driving. We have two levels of drunk driving. The more serious level is: "Driving under the influence" (DUI) means driving when a person has consumed enough alcohol (or possibly drugs) to affect them to a degree that the person is substantially incapable to exercise clear judgment, sufficient physical control, or due care in the safe operation of a vehicle. " The presumptive level of alcohol is 0.10 grams of alcohol per two hundred ten liters of breath. The lesser offense is: "Driving while ability impaired" (DWAI) means driving a vehicle when a person has consumed alcohol which affects the person to the slightest degree so that the person is less able than the person ordinarily would have been to exercise clear judgment sufficient physical control, or due care in the safe operation of a vehicle. The presumptive level of alcohol is 0.05 or more grams of alcohol per two hundred ten liters of breath.