Most Illinois drivers are aware of the effects that alcohol has on driving. However, many people believe that having just one drink means that they can still safely operate a motor vehicle.

Alcohol metabolism depends on several different factors and differs for everyone. A blood alcohol concentration (BAC) level test measures the amount of alcohol in the blood. Impairment level varies depending on the BAC.

BAC levels between .02% and .05%

A BAC level of .02% relaxes the body, alters the mood and makes the body slightly warmer. Drivers with this BAC have a difficult time performing two tasks at the same time and may find tracking moving targets to be difficult. As BAC levels increase to .05%, good feelings and a release of inhibitions cause impaired judgment and exaggerated behaviors. Drivers with a BAC of .05% may find it difficult to steer a vehicle and experience reduced coordination.

BAC levels over .08%

Those with a BAC of .08% have reached the legal limit in Illinois, as well as in every state in the United States. A 170-pound man typically reaches this level after drinking four alcoholic drinks in one hour on an empty stomach. Poor muscle coordination and impaired reasoning and memory make it difficult to operate a vehicle safely. At .08% and above, drivers typically swerve in-between lanes, have a difficult time controlling the speed of the vehicle and may blackout.

Determining BAC levels in a traffic stop

Law enforcement officers use several techniques to determine if a driver is driving under the influence. When a driver is stopped on suspicion of a DUI, the BAC level must be correctly determined for the evidence to hold up in court. Most DUI cases center on this evidence. A police officer who was not adequately trained in using a Breathalyzer may not have collected the BAC level correctly. A lawyer might be able to challenge the BAC results then. This may result in the charges being reduced or dropped.