For a driver age 21 or older in an ordinary car, what BAC level meets Colorado’s DUI-per-se threshold at the time of driving?
Correct answer: 0.08 or more.
The DUI-per-se threshold is 0.08. The law also addresses testing within two hours after driving. A result below 0.08 is not permission to drive while impaired.
Source: Colorado Revised Statutes 2026, section 42-4-1301 (2)(a); current on September 13, 2026. ↗
An adult driver says, “My BAC is 0.07, so Colorado cannot treat my driving as alcohol-impaired.” Is that correct?
Correct answer: No. Being below 0.08 does not rule out impaired driving.
A BAC above 0.05 but below 0.08 permits an inference of impaired ability and may be considered with other evidence. It is not the 0.08 DUI-per-se threshold.
Source: Colorado Revised Statutes 2026, section 42-4-1301 (6)(a)(II) and (6)(b); current on September 13, 2026. ↗
Alcohol makes a driver slightly less able than usual to use clear judgment and control the car, without making the driver substantially incapable. Which Colorado impairment definition fits?
Correct answer: Driving while ability impaired, or DWAI.
DWAI includes alcohol or drugs affecting ability to the slightest degree so the driver is less able than usual to exercise judgment, control or due care. A driver need not appear completely incapacitated.
Source: Colorado Revised Statutes 2026, section 42-4-1301 (1)(b) and (1)(g); current on September 13, 2026. ↗
A drug has made a driver substantially incapable of exercising clear judgment or sufficient physical control. Which rule applies even without alcohol?
Correct answer: Colorado’s prohibition on driving under the influence.
DUI covers alcohol, drugs or a combination when their effects substantially prevent safe judgment, physical control or due care. Alcohol is not a required ingredient in a drug-DUI violation.
Source: Colorado Revised Statutes 2026, section 42-4-1301 (1)(a) and (1)(f); current on September 13, 2026. ↗
A 20-year-old drives with a breath-alcohol result of 0.03 at the time of driving. Does being below 0.08 avoid Colorado’s underage drinking-and-driving rule?
Correct answer: No. The under-21 rule includes BAC from 0.02 through 0.05.
Colorado’s UDD provision applies to a driver under 21 with a breath-alcohol result at least 0.02 and not more than 0.05. Other impaired-driving offenses depend on their own requirements.
Source: Colorado Revised Statutes 2026, section 42-4-1301 (2)(d)(I); current on September 13, 2026. ↗
A driver is legally authorized to use medical marijuana. Does that authorization excuse driving while it impairs the driver?
Correct answer: No. Legal authorization to use a drug is not a defense to impaired driving.
The law specifically says entitlement to use a drug, including medical marijuana, is not a defense to DUI or DWAI. Permission to use a substance does not mean permission to drive while affected.
Source: Colorado Revised Statutes 2026, section 42-4-1301 (1)(e); current on September 13, 2026. ↗
A driver’s ability is impaired by a combination of alcohol and a drug, rather than by either one alone. Does Colorado’s impaired-driving law cover the combination?
Correct answer: Yes. It expressly covers alcohol combined with one or more drugs.
DUI and DWAI both cover alcohol, drugs and combinations of them. The relevant issue is their effect on safe driving under the applicable definition.
Source: Colorado Revised Statutes 2026, section 42-4-1301 (1)(a), (1)(b), (1)(f) and (1)(g); current on September 13, 2026. ↗
A blood test shows five nanograms or more of delta-9 THC per milliliter of whole blood. What does Colorado law say this result permits?
Correct answer: An inference that the driver was under the influence of drugs.
The statute calls this a permissible inference, not an automatic conviction or a safe-driving cutoff. The DUI definition and other competent evidence still matter.
Source: Colorado Revised Statutes 2026, section 42-4-1301 (6)(a)(IV) and (1)(f); current on September 13, 2026. ↗
What action brings a motor-vehicle driver within Colorado’s expressed-consent testing law?
Correct answer: Driving a motor vehicle in Colorado.
A person who drives a motor vehicle on Colorado streets, highways or elsewhere in the state is deemed to have expressed consent to this law. Specific testing requests must still meet the law’s conditions.
Source: Colorado Revised Statutes 2026, section 42-4-1301.1 (1); current on September 13, 2026. ↗
An officer has probable cause to believe an adult driver committed an alcohol-related driving offense and lawfully directs a formal blood or breath test. What is required?
Correct answer: Take and complete the required test and cooperate with it.
For the qualifying alcohol-related offenses, expressed consent requires taking, completing and cooperating with the formal test. This is different from a voluntary preliminary roadside screen.
Source: Colorado Revised Statutes 2026, section 42-4-1301.1 (2)(a)(I); current on September 13, 2026. ↗
For a formal alcohol test, a 30-year-old driver requests a blood test. No medical or extraordinary circumstance changes the normal choice. Which sample should be tested?
Correct answer: The driver’s blood.
Under the normal alcohol-testing provision, a driver 21 or older who requests blood receives a blood test. Special medical or extraordinary circumstances can affect the procedure.
Source: Colorado Revised Statutes 2026, section 42-4-1301.1 (2)(a)(I) and (2)(a.5); current on September 13, 2026. ↗
A driver age 25 lawfully chooses not to have blood drawn for a formal alcohol test and can complete a breath test. No special exception applies. Which test follows?
Correct answer: A breath test.
For an adult’s normal alcohol-test election, requesting no blood draw leads to a breath sample. It does not cancel the obligation to complete testing.
Source: Colorado Revised Statutes 2026, section 42-4-1301.1 (2)(a)(I); current on September 13, 2026. ↗
After choosing a formal alcohol test, a driver wants to switch simply because of a change of mind. No medical or extraordinary circumstance applies. Is that an unrestricted choice?
Correct answer: No. The chosen test normally must be completed.
Once blood or breath is elected, the driver generally cannot change the election. The statute provides specific exceptions, including qualifying extraordinary circumstances, rather than an unrestricted right to switch.
Source: Colorado Revised Statutes 2026, section 42-4-1301.1 (2)(a)(II) and (2)(a.5); current on September 13, 2026. ↗
A driver cannot physically complete a breath test because of an injury. What does Colorado’s expressed-consent provision specify?
Correct answer: Use a blood test for the alcohol sample.
When injury, illness or another listed physical condition prevents taking or completing the breath test, the statute provides for a blood test. Genuine physical inability is not treated as a mere preference to change tests.
Source: Colorado Revised Statutes 2026, section 42-4-1301.1 (2)(a)(II); current on September 13, 2026. ↗
A power outage beyond the officer’s control prevents the elected breath test within the required period. The officer explains this and directs a blood test. What must the driver do?
Correct answer: Cooperate with and complete the alternative test.
Qualifying extraordinary circumstances can require the other test. Complying with the officer’s required change is not itself a refusal; failing to complete that alternative can be.
Source: Colorado Revised Statutes 2026, section 42-4-1301.1 (2)(a.5)(I)-(IV); current on September 13, 2026. ↗
After a qualifying formal alcohol-test request, how must a driver cooperate with the sample-collection timing?
Correct answer: Allow the sample to be obtained within two hours of driving.
The cooperation duty is intended to allow blood or breath collection within two hours of driving. It is not permission to delay until the end of that period.
Source: Colorado Revised Statutes 2026, section 42-4-1301.1 (2)(a)(III); current on September 13, 2026. ↗
