A person's driving ability begins to become impaired when BAC is what value before becoming steadily worse?

The correct answer is associated with a Blood Alcohol Concentration (BAC) of .01. At this level, a person's driving ability begins to show signs of impairment. Research indicates that even small amounts of alcohol can affect coordination, judgment, and reaction times, which are critical for safe driving.

As BAC increases, the effects on driving abilities become more pronounced. Many jurisdictions, including the United States, legally define impairment as having a BAC of .08 or higher; however, every incremental increase in alcohol consumption can degrade driving performance. Thus, it is important to recognize that impairment begins even at lower BAC levels, emphasizing the importance of not consuming alcohol if one intends to drive, regardless of whether they are over the legal limit or not.

Other BAC levels listed, such as .05, .08, and .10, represent higher degrees of impairment; these values are typically where statutory limits are established for legal repercussions, but they do not capture the fact that impairment can commence at a much lower BAC level.