Implied Consent: Can You Refuse a Blood, Breath, or Urine DUI Test?

Find out what implied consent is and what would happen if you refuse a blood, breath, or urine test if you are pulled over.

Updated by Stacy Barrett, Attorney · UC Law San Francisco

During a DUI or traffic stop, an officer who suspects a driver is impaired by drugs or alcohol will typically ask the driver to perform field sobriety tests. Depending on the driver's performance and other signs and symptoms of intoxication, the officer might place the driver under arrest.

After a DUI arrest, an officer will typically ask the suspect to take a breath, blood, or urine test (collectively called "chemical tests"). Blood or breath tests can determine a suspect's blood alcohol content (BAC). Blood or urine tests check for the presence of drugs in a suspect's system.

Many drivers want to know: Can you lawfully refuse to submit to a chemical test? If not, what happens if you refuse?

Every state has some form of "implied consent" law that covers DUI chemical testing. Implied consent means that by driving on state roadways, the driver impliedly agrees to take a chemical test if lawfully arrested for driving under the influence.

DUI Testing and Your Rights

Implied consent laws require drivers who are lawfully arrested for driving under the influence to submit to a chemical test. A DUI arrest is lawful only if the officer has reasonable grounds to believe that the suspect was operating while under the influence of drugs or alcohol. Reasonable grounds might include things like poor field sobriety test performance, reckless driving, and smelling like alcohol.

Drivers are typically given the option of taking a breath or blood test. Breath testing is the fastest and easiest. Blood testing directly measures the amount of alcohol in someone's bloodstream and can be retested, but it's invasive. Urine tests are disfavored because they are the least accurate and most complicated to collect.

In most states, drivers don't have the right to talk to an attorney before deciding whether to take a chemical test. But, unless an officer gets a warrant to take your blood, you have a "right" to refuse to test. However, exercising your right to refusal comes with consequences.

Consequences of Refusing to Test

So, what happens if you refuse a breathalyzer or blood or urine test? The purpose of implied consent laws is to get drivers to comply with DUI chemical testing. The way implied consent laws achieve this purpose is by penalizing drivers who refuse to test.

The Foundation for Advancing Alcohol Responsibility ( has a map of implied consent laws with a summary of penalties in each state. Here are some of the more common penalties for refusing DUI chemical testing.

License Suspensions for Implied Consent Violations

When a driver unlawfully refuses a chemical test, the officer will typically issue a notice of license suspension to the driver. The length of a refusal suspension depends on state law and the driver's history. But it's common for refusal suspensions to be one or two years. The length of a refusal suspension is usually longer than the suspension (sometimes double) that would result from a failed test (a result that shows a BAC that's above the legal limit) or a DUI conviction.

In most states, drivers who lose their license for a failed DUI chemical test or DUI conviction can get a restricted license for driving to and from places like work and school. But drivers who refused to test are sometimes ineligible for a restricted license.

Refusals Can be Used Against You at Trial

In many DUI cases, the driver's chemical test results are critical for the prosecution to prove the charges. So, when a driver refuses to test, it makes it more difficult for the prosecution to prove its case.

To counteract this benefit to drivers who refuse to test, prosecutors are typically allowed to introduce evidence of the driver's refusal at trial and argue that it shows a "consciousness of guilt." So, even without chemical test results, a driver can still be found guilty of driving under the influence.

Criminal Penalties for Refusing DUI Testing

In most states, an unlawful DUI test refusal will result only in administrative license-related penalties imposed by the Department of Motor Vehicles. But a few states have criminalized unlawful refusals. In other words, drivers who refuse testing can be charged with a criminal offense separate from a DUI charge. Drivers who are convicted of an unlawful refusal normally face fines and jail time similar to what would result from a DUI conviction.

Talk to a Lawyer

If you've been arrested for a DUI, talk to a lawyer as soon as possible. An experienced DUI lawyer can help you understand your legal rights and get you the best possible outcome in your case.

Learn more about what to do about an attorney if you're arrested for a DUI. When you're ready, you can connect with a lawyer directly from this page for free.

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