By Lark Lewis, J.D. | Legally reviewed by Melissa Bender, Esq. | Last reviewed December 28, 2023
This article has been written and reviewed for legal accuracy, clarity, and style by FindLaw’s team of legal writers and attorneys and in accordance with our editorial standards.
The last updated date refers to the last time this article was reviewed by FindLaw or one of our contributing authors. We make every effort to keep our articles updated. For information regarding a specific legal issue affecting you, please contact an attorney in your area.
Perhaps you or someone you know has been pulled over on suspicion of driving under the influence (DUI). In that case, you may have questions about the process.
This article answers frequently asked questions (FAQ) about driving under the influence (DUI), legal limits, DUI defenses, and finding the right attorney after you've been charged with a DUI offense.
The legal limit for blood toxicity depends on your age. Having a blood alcohol content (BAC) of .08% or higher is considered per se driving under the influence (DUI) or driving while intoxicated (DWI). If you're under the legal drinking age of 21, in almost all states you'll be considered to be driving under the influence if you have a blood alcohol content greater than .01% or .02%. The exact amount varies by state.
In general, it's illegal for you to drive while you're impaired by drugs or alcohol. That includes prescription drugs. Being impaired means there's enough alcohol or drugs in your system to prevent you from thinking clearly and driving safely. According to many studies, people are often impaired well before they consider themselves drunk or stoned.
Police generally have three different methods of determining whether there's probable cause to believe a motorist is under the influence, which are: observing erratic driving, field sobriety tests, and chemical blood alcohol level tests. Each is discussed below.
In general, police officers will pull you over if they notice you're showing any signs of driving under the influence. These signs include:
Suppose you have a good reason for driving erratically. In that case, the officer may let you go with only a ticket or a warning. However, officers will look to see if your eyes are blurred or bloodshot or if your breath smells like alcohol.
If, after stopping you, a law enforcement officer has reasonable suspicion that you might be driving under the influence, the officer will likely get you out of your car to do field sobriety tests. These tests can include:
The officer will also carefully watch your eyes for pupil dilation. If you fail any of these tests, the officer will likely ask you to take a chemical test.
If you fail a field sobriety test, a police officer will likely take you to the police station to perform a more accurate blood alcohol level test. This type of test typically requires testing a blood, urine, or breath sample. The blood test is straightforward and measures the amount of alcohol in your system. The urine and breath tests use a mathematical formula to derive your blood alcohol level from the sample.
If your test results show a blood alcohol level above .08%, you will be found guilty of a DUI unless you can convince the judge that you weren't impaired or unsafe. Many criminal defense attorneys base their drunk driving defense on challenging the mathematical formula used in the tests.
You can refuse to take a breathalyzer or a chemical blood alcohol level test, but you'll invoke an implied consent law if you refuse to submit to a test. This will likely result in a suspension of your driver's license and loss of driving privileges for some time. This is the case even if you're found not guilty in court.
In addition, if your case goes to trial, the prosecutor can tell the jury that you refused to take a chemical test. This may look bad for your drunk driving defense and may lead to the revocation of your license.
Whether you can consult with an attorney before deciding which chemical test to take after being stopped for DUI depends on the laws of your state. For example, in Arizona, you can talk to a lawyer before deciding to take a chemical test. However, other states don't allow you to consult with an attorney before a test.
Whether or not the police can ask you questions after pulling you over and before reading your Miranda rights depends on the circumstances. It also depends on whether you're in the custody of the police. During a roadside traffic stop, you're not considered to be in police custody. Therefore, the police can ask you questions without reading you your Miranda warning.
Once you're in police custody, however, the police must read you your rights before asking you any questions. If they don't, any answers you give may be inadmissible in court. To be in custody, you must believe you're not free to leave a situation.
Police can legally stop you at a roadblock and ask you to wait to answer some questions if the police use a neutral policy for determining which motor vehicles to stop. Police can single out automobiles at roadblocks if they have a good reason. An example of a legitimate reason would be suspecting that you're driving under the influence of alcohol.
The best way to learn more about traffic stops and DUI charges is to speak with a DUI attorney near you. A defense lawyer reviewing your DUI case can help ensure the best possible outcome after a DUI arrest. A DUI lawyer can help you navigate the court system, whether this is your first offense or your second DUI conviction.
Contact a qualified DUI attorney to make sure your rights are protected.
Get tailored advice and ask your legal questions. Many attorneys offer free consultations.
Learn more about FindLaw’s newsletters, including our terms of use and privacy policy.