Legal Definitions - driving under the influence

DUI stands for Driving Under the Influence.

This legal term refers to the offense of operating a motor vehicle while one's physical or mental abilities are significantly impaired by alcohol, drugs (including prescription medications), or other substances. The impairment makes it unsafe for the individual to drive, even if they do not feel completely "drunk" or "high."

• Example 1: Sarah had three glasses of wine over dinner and felt a bit lightheaded. Despite believing she was "okay to drive," her reaction time was slower, and she had difficulty maintaining a consistent speed. A police officer observed her weaving slightly and pulled her over.

  This is an instance of driving under the influence because Sarah's consumption of alcohol impaired her mental and physical faculties (slower reaction time, difficulty with speed control), making her operation of the vehicle unsafe, regardless of whether she felt fully intoxicated.

• Example 2: Mark was prescribed a new pain medication with a warning label stating it could cause drowsiness. He took the medication and, needing to pick up groceries, decided to drive. While driving, he started to feel very sleepy and briefly drifted into another lane.

  Mark's situation illustrates driving under the influence because his ability to safely operate his car was impaired by the side effects of his prescription medication, even though it was legally prescribed. The impairment (drowsiness, drifting) made his driving dangerous.