In every state, it is a crime for a driver to operate a vehicle while impaired by the effects of alcohol or drugs. The specific offense may be called driving under theinfluence (DUI), driving while intoxicated (DWI), operating under the influence (OUI), and even operating a motor vehicle intoxicated (OMVI). Whatever the specific title, DUI laws make it unlawful for aperson to operate a car, truck, motorcycle, or commercial vehicle if:
• The driver's ability to safely operate the vehicle is impaired by the effects of alcohol, illegal drugs, prescribedmedications such as painkillers, or even over-the-counter medications such as antihistamines; or
• The driver is intoxicated at a level above established DUI standards, such as blood-alcohol concentration(BAC).
Field Sobriety and Chemical Tests
When a law enforcement officer makes a vehicle stop and suspects that the driver may be intoxicated, the officer will conduct a "field sobriety" test on thedriver, and may ask for his or her consent to some form of chemical test for intoxication.
Field sobriety tests usually involve a police officer asking a driver to perform a number of tasks that assessany impairment of the person's physical or cognitive ability. Examples of field sobriety tests include having the driver walk a straight line, heel to toe; having he or she recite the alphabetbackwards; and the officer's use of the "horizontal gaze nystagmus" (eye and penlight) test.
Chemical tests can be conducted during the vehicle stop, using a Breathalyzer that measures a driver'sblood-alcohol concentration (BAC), or at a hospital, where urine and blood tests can be performed. Many states allow a driver suspected of DUI to choose which type of chemical test is administered.
Refusing aChemical Test: "Implied Consent" Laws
All states have "implied consent" laws that require vehicle drivers to submit to some form of chemical test, such as breath, blood, or urine testing, if...