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

The legal blood alcohol concentration (BAC) limit for drivers over 21 years old is 0.08%. This standard is established to promote road safety by ensuring that drivers are not impaired by alcohol while operating a vehicle. At a BAC of 0.08%, an individual's ability to judge distances, coordinate movements, and respond to emergencies is significantly impaired, increasing the risk of accidents. Laws uphold this limit to deter drinking and driving and to protect both the driver and others on the road.

The other options reflect BAC levels that may not legally impair drivers but do not meet the threshold set by law. For instance, while a BAC of 0.05% might suggest some level of impairment, it is not considered illegal under most jurisdictions for those over 21. A BAC of 0.10% or higher is typically associated with severe impairment and greater legal consequences, while 0.12% is even more dangerous. Therefore, the limit of 0.08% serves as a clear legal standard for responsible driving.