What Is Suspicion of DUI?

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DUI is an acronym that represents the act of driving under the influence of alcohol or drugs. An officer of the law may stop any individual that he or she deems to be under the influence. When an officer stops an individual for suspicion of DUI, he gives the person several tests that either validate or eradicate such suspicion. If an individual fails to pass DUI tests, he will be arrested for suspicion of DUI. The court must show proof of DUI in order to get a conviction. Individuals may exhibit several suspicions of DUI.

Initial Cause

The initial inquiry for suspicion of DUI is typically based on one factor: erratic driving. Intoxicated individuals usually exhibit their intoxication by weaving in and out of lanes while driving too fast or slow. When an officer of the law sees such behavior, he is inclined to believe that the driver is under the influence and will initiate a traffic stop. After initiating the stop, the smell of alcohol coming from the driver or vehicle encourages the officer's suspicion of DUI and gives him the right to conduct a full-length investigation, not limited to vehicle search and field tests.

Field Tests

During the investigation, the officer will ask the driver to exit the vehicle and administer a series of field sobriety tests that include the heel-to-toe walk, one leg stand, and horizontal gaze nystagmus, which occurs when the eyeball gazes and involuntarily jerks from side to side. Such activity the brain's inability to control the muscles of the eye because of alcohol or depressant consumption. An officer will typically shine a flashlight in the individual's eyes to search for signs of horizontal gaze nystagmus. If an individual exhibits such behavior, the heel-to-toe-walk and one leg stand tests will be given.

When administering the heel-to-toe walk, the officer requires the individual to walk a straight line from heel to toe. Likewise, drivers given the one-leg stand test will be asked to stand with one leg on the ground, and the other extended off the ground for a number of seconds. Failure to pass all tests given will result in the individual's arrest for suspicion of DUI.

Blood Alcohol Test

The blood alcohol test is administered at the police station. The test either takes a blood or breath sample from the accused individual and evaluates it in conjunction with the legal blood alcohol concentration, or BAC. While legal blood alcohol concentrations vary by jurisdiction, the level that is generally acceptable by law enforcement in the United States and United Kingdom is 0.8 percent. Individuals found to have more than this percentage in their bloodstream at the time of the test will be arrested for suspicion of DUI. In addition, any individual refusing to take a blood alcohol concentration test will be arrested for suspicion of DUI.


While suspicion of DUI may result in jail time, conviction of DUI carries severe consequences not limited to jail or prison time, and restriction of license. Although penalties vary by state, courts penalize many first time offenders with license restrictions, jail time and fines. Individuals who repeatedly offend may be punished with several years in state prison and ignition interlock installation may be required for the vehicle if their license is not revoked.