After a police officer has conducted a traffic stop and suspects a DUI violation, he or she will conduct one or more tests to determine whether or not the motorist is impaired. Usually the process begins with a field sobriety test, in which the officer asks the driver to perform a set of tasks that would be difficult for a drunk driver to complete. The officer then uses an instrument to measure an individual's blood-alcohol concentration (BAC), most commonly called a breathalyzer. This section covers a range of topics pertaining to sobriety tests and their use as evidence in a DUI case.
The first thing a police officer must do at a DUI stop is to determine how intoxicated the driver is, and one of the best ways to do that is to discover a driver's blood-alcohol content (BAC). This article has some useful information on the different types of BAC tests.