What is the legal blood alcohol concentration (BAC) limit for drivers over 21 in Illinois?

The legal blood alcohol concentration (BAC) limit for drivers over 21 in Illinois is set at 0.08%. This means that a driver is considered legally impaired if their BAC is at or above this level. This limit is based on extensive research indicating that impairment significantly increases at this concentration, affecting a driver's ability to operate a vehicle safely. Essentially, reaching a BAC of 0.08% indicates that motor skills, reaction time, and decision-making abilities are adversely impacted, leading to a greater risk of accidents.

The other options do not reflect the state's legal standards for driving under the influence. A BAC of 0.05% is below the legal limit but may still carry penalties for drivers under a zero-tolerance law or in the case of reckless behavior. A BAC of 0.10% exceeds the legal limit, leading to more severe consequences. Lastly, 0.00% might apply in specific circumstances, such as for underage drivers or commercial vehicle operators, but it is not the standard for drivers over 21. Understanding this limit is crucial for responsible driving and ensuring safety on the roads.