Impaired to the Slightest Degree

DUI: Impaired to the Slightest Degree


In Arizona, a person over 21 years old with a non-commercial license may be charged with a standard DUI if they are found to be driving with a blood alcohol count (BAC) of .08. However, this is not the only circumstance that can lead to a DUI in Arizona. There’s another law in Arizona that is meant to hold drivers responsible if they are found to be “impaired to the slightest degree.” This looks at the quality of a person’s driving in addition to the actual BAC.

What is Impaired to the Slightest Degree?

Arizona law states that a person is not allowed to drive or be in physical control of a vehicle if they are under the influence of an intoxicating liquor, any drug, or a vapor with a toxic substance that causes that person’s driving ability to be “impaired to the slightest degree.”

This charge relies more heavily on the observations of the arresting officer and/or any witnesses. This is in contrast to a DUI that results from a blood alcohol test or a breathalyzer test that shows a BAC of .08 for regular drivers over 21 years, .04 for commercial drivers, or .02 for minors.

The fact that a person can be charged with a DUI even if their BAC is lower than the legal limit is something many Arizona residents may not know. If a person is convicted of a “slightest degree” DUI it will still go on their record as a Class 1 Misdemeanor, and can carry similar penalties. The charge is also not necessarily based on the isolated incident. Prior convictions from the last seven years can be brought up in an effort to influence the court’s decision, so long as it is proven that that information is relevant.

Determining Degree of Impairment

While a BAC test can be administered for alcohol use, it is more difficult to determine a measure of impairment for other substances. The slightest degree provision gives police license to use road side sobriety tests and other measures to determine impairment. A person may also be more likely to be charged with a Slightest Degree DUI if they are driving when the are very tired or are fighting an illness.

A commercial driver can be charged with a DUI with a BAC of .04, and a minor may be charged if their BAC is as low as .02. However, non-commercial drivers over 21 years old have a higher threshold, even under “slightest degree.” If a DUI case goes to trial, there is a presumption that a BAC under .05 means the driver was not intoxicated. If the BAC is between .05 -.08, the court will look at the evidence as to whether or not the driving ability was lessened due to their limited consumption. A BAC of .08 and up brings an assumption that the driver was intoxicated, and it is not necessary to bring up other evidence.

How You Can Help Your Defense

If you are being charged with a slightest degree DUI, or any DUI, it is important to consider hiring your own lawyer to represent you rather that just using a court appointed attorney. Your own attorney can help you to assert your rights and take a close look at the circumstances of your arrest. Required circumstances in a DUI arrest include

  • Being able to prove reasonable suspicion to detain. There should be a notable impairment to a person’s driving or another violation occurring such as speeding or a seatbelt violation.
  • Following proper procedures as to informing a person of their Miranda Rights

If these procedures are not followed, a good lawyer may be able to get your case dismissed. It is also sometimes possible to have the results of a breathalyzer disregarded since their accuracy is not scientifically accurate.

At R&R Law, our attorneys take each case seriously and will investigate as needed to make sure everything has been handled correctly. We will hold the prosecution responsible if they fail to honor your rights. We can look at the circumstances and advise you on whether or not you should request a trial. If it is necessary to seek help for alcohol or drug use, we can help you find the proper resources and use your decision to get help to positively impact your case. Having a DUI on your record can strongly impact your life. By consulting with our team at R&R Law you can put control of the situation back in your own hands. Contact us for a free case evaluation today!