What is considered a failing Blood Alcohol Content (BAC) level for individuals over 21?

The Blood Alcohol Content (BAC) level that is legally considered as failing for individuals over 21 in Massachusetts is 0.08. This standard is used nationwide and signifies the point at which a person's ability to operate a vehicle safely is significantly impaired due to alcohol consumption. At this level, drivers are presumed to be driving under the influence, leading to legal penalties if caught.

Levels below this, such as 0.04, are also important; however, they are not considered legally impaired for individuals over 21. Higher levels, like 0.1 and 0.15, indicate an even greater impairment and carry more severe legal consequences but are beyond the threshold that defines legal intoxication. Therefore, 0.08 is the critical cutoff that establishes whether a driver is legally considered impaired.