DUI, DWAI and how alcohol works

Key points

1. DWAI means impaired to the slightest degree. DUI means substantially incapable of safe driving.

   Source: Handbook p. 3

   “DWAI means the driver is impaired to the slightest degree. DUI means the driver is substantially incapable of safe driving.”
   Colorado Driver Handbook, Handbook p. 3

2. You can be convicted of DUI per se if your BAC is greater than 0.08%.

   Source: Handbook p. 3

   “A driver may also be convicted of DUI per se if the driver's BAC is greater than 0.08%.”
   Colorado Driver Handbook, Handbook p. 3

3. Licenses may be revoked for a BAC over .08, over .02 under 21, or over .04 for a CDL driver.

   Source: Handbook p. 3

   “based on a BAC over .08 or over .02 if the driver is under 21, or over .04 for a CDL driver.”
   Colorado Driver Handbook, Handbook p. 3

4. An open container of alcohol or marijuana in the passenger area on a public road is unlawful.

   Source: Handbook p. 3

   “It is unlawful for someone to either possess an open container of alcohol or possess an open container of marijuana while in the passenger area of a motor vehicle that is on a public road.”
   Colorado Driver Handbook, Handbook p. 3

5. A standard drink is 12 ounces of beer, 5 ounces of wine or 1.5 ounces of spirits, all with the same alcohol.

   Source: Handbook p. 3

   “A standard drink is defined as 12 ounces of beer, 5 ounces of wine, or 1.5 ounces of distilled spirits, all of which contain the same amount of alcohol.”
   Colorado Driver Handbook, Handbook p. 3

6. Only time sobers you. On average, BAC drops by 0.015% per hour.

   Source: Handbook p. 3

   “On average, a person's BAC will drop by 0.015% per hour.”
   Colorado Driver Handbook, Handbook p. 3

7. Alcohol affects people differently even when they drank the same amount over the same time.

   Source: Handbook p. 3

   “Alcohol in the body affects people differently, even if they have consumed the same amount of alcohol over the same time period.”
   Colorado Driver Handbook, Handbook p. 3

Numbers to know

3 questions from the Colorado practice test

1. 1. For a Colorado driver age 21 or older, which BAC is identified as DUI per se?

   1. 0.02%
   2. 0.04%
   3. 0.08%
   4. 0.05%
   Show answer

   0.08%. For drivers age 21 and older, the handbook identifies DUI per se at a BAC greater than 0.08 percent. The 0.05 percent figure is associated with the first DWAI table entry, while 0.04 percent is the threshold noted for a CDL driver. A BAC number does not excuse unsafe behavior at a lower level, since impairment can also be established through driving conduct and observed symptoms. Separate the per se threshold from every other alcohol rule.

2. 2. What does DWAI mean under Colorado's impaired-driving definitions?

   1. The driver is impaired to the slightest degree
   2. The driver is substantially incapable of safe driving
   3. The driver has a BAC below every legal threshold
   4. The driver has refused every chemical test
   Show answer

   The driver is impaired to the slightest degree. DWAI means driving while ability is impaired to the slightest degree. That standard is lower than the handbook's description of DUI, which means the driver is substantially incapable of safe driving. The remaining choices invent a BAC guarantee, a testing refusal rule, or another threshold that the definition does not use. The practical lesson is that a driver need not appear profoundly intoxicated before impaired-driving consequences can apply. Any observed impairment can matter.

3. 3. Which serving is defined as one standard drink under Colorado's handbook guidance?

   1. 16 ounces of beer, 6 ounces of wine, or 2 ounces of distilled spirits
   2. 8 ounces of beer, 4 ounces of wine, or 1 ounce of distilled spirits
   3. 12 ounces of beer, 5 ounces of wine, or 1.5 ounces of distilled spirits
   4. A mixed drink is always one standard drink regardless of its ingredients
   Show answer

   12 ounces of beer, 5 ounces of wine, or 1.5 ounces of distilled spirits. Colorado treats several differently sized servings as comparable alcohol amounts: 12 ounces of beer, 5 ounces of wine, or 1.5 ounces of distilled spirits. The smaller measurements in the choice “8 ounces of beer, 4 ounces of wine, or 1 ounce of distilled spirits” understate the handbook's examples, while the larger measurements in the choice “16 ounces of beer, 6 ounces of wine, or 2 ounces of distilled spirits” overstate them. The choice “A mixed drink is always one standard drink regardless of its ingredients” is unsafe because a mixed drink can contain more than one standard serving depending on its recipe. When estimating alcohol exposure, identify the beverage type and measure rather than relying on the glass's appearance.

Source: the Colorado Driver Handbook, Driving Under the Influence. This lesson is a plain English summary, not the law itself; where it differs, the manual and the statute govern. Last checked 2026-09-27.