Implied Consent and Refusal to Take Blood, Breath, or Urine Test

When police suspect someone of drunk driving, they will normally ask the person to perfect certain tests. DUI testing generally falls into one of two categories: field sobriety tests (FSTs) and chemical testing.

Field Testing

Generally, police use FSTs to get a better idea of whether a driver is under the influence of drugs or alcohol. There are three "standardized FSTs" that police often administer during DUI investigations. Studies have been done that purportedly showed these standardized tests are reliable for gauging intoxication. The standardized FSTs are called the "horizontal gaze nystagmus test," "one-leg-stand test," and "walk-and-turn test." As a general rule (and unlike with chemical testing), there is no legal penalty for refusing to take an FST.

Implied Consent Laws

In most cases, if an officer has probable cause to believe that you are driving under the influence, "implied consent laws" require you to take a chemical test (using your blood, breath, or urine) to determine your blood alcohol content (BAC). Implied consent laws say that by just driving on the road, you are agreeing to take a chemical test to assess your BAC. Implied consent laws vary by state—particularly with regard to which test is required—but every state has them.

Timing of the Chemical Tests

In some states, a chemical test must be given within a particular timeframe—usually within a few hours of the time that you were driving. However, even if you took the test after that time, you could still be found guilty of a DUI. To prove a DUI, the prosecution can either prove a BAC of .08% or more (less for underage drivers) or actually driver impairment. So, a BAC test isn't absolutely necessary for a DUI conviction.

Refusing to Take the Test

Drivers who unlawfully refuse to take the test face serious consequences—normally, worse than if you were just found guilty of driving under the influence. Depending on the circumstances, a refusal can lead to license suspension, jail time, fines, and having to install an ignition interlock device (IID). Additionally, if your case goes to trial, the prosecution can typically use your refusal against you—arguing that you knew you were intoxicated and that's why you refused to take the test.

Consequences of Refusal in Your State