Alcohol, Drugs, and Impaired Driving
What this domain covers
Impaired-driving questions test Colorado's alcohol limits, the meaning of impaired, the express-consent law, and the effects of alcohol, cannabis, and other drugs on driving. Colorado enforces both DUI and DWAI.
Limits and laws
- DUI: blood or breath alcohol concentration of 0.08 or higher, or driving while substantially incapable due to alcohol or drugs.
- DWAI: 0.05 to 0.079, or driving while ability is impaired to the slightest degree. You can be convicted below 0.08.
- Under 21: 0.02 or higher is a violation. Colorado's zero-tolerance approach means even one drink can be over the limit for a young driver.
- Commercial drivers: 0.04 or higher.
- Colorado's express-consent law means that by driving, you consent to a chemical test if an officer has probable cause. Refusing can lead to license revocation even before a criminal case ends.
- Open containers of alcohol in the passenger area of a vehicle are prohibited. Cannabis can also lead to DUI; impairment is judged by driving behavior, not only by a test.
Effects
Alcohol slows reaction time, reduces inhibition and judgment, impairs tracking and lane position, and causes tunnel vision. Cannabis can slow reaction time and impair attention and lane control. Prescription and over-the-counter drugs can impair driving; read labels and ask a pharmacist. Combining substances multiplies impairment.
Worked example
A 20-year-old driver has a beer at a party, waits an hour, drinks coffee, and drives home with a 0.03 BAC. The driver believes they are legal because 0.03 is below 0.08. In Colorado, the applicable limit is 0.02, so the driver is over the limit for a driver under 21. Coffee and time may reduce alcohol slightly, but they do not make the driver legal at the time of driving. The correct choice is not to drive.
Traps that cost marks
The adult 0.08 limit does not apply to everyone. 'I feel fine' is not a defense; DWAI can apply below 0.08. A refusal is not a way to avoid consequences. Do not assume a prescription drug is safe to drive on. Do not use 'one drink per hour' as a reliable plan.