The concentration of alcohol in the bloodstream is directly related to the level of impairment a person experiences. This impairment affects several different areas, including muscle coordination, reasoning, perception, judgment and self-control. When it comes to operating a vehicle, any amount of alcohol can affect the mind and body of the person behind the wheel to varying degrees.
A blood alcohol concentration (BAC) level of .08 is the legal limit that defines when a person is intoxicated in all 50 states. A .08 BAC will lead to a DUI arrest and conviction, because of the danger this level of alcohol poses to the driver, as well as to others. Blood tests, breathalyzer tests and ignition interlock devices are all used to measure the BAC in a person suspected of driving under the influence, as well as those that have been convicted of a DUI offense.