The first abilities typically impaired as BAC rises include:

As BAC rises, alcohol typically first affects judgment and inhibition — leading to poorer decisions and lowered self-control — followed by impaired coordination, balance, and reaction time as consumption continues. This progression explains why an intoxicated customer may make risky choices before showing obvious physical signs like stumbling. For servers, it underscores the importance of early monitoring: by the time coordination is visibly affected, the customer's judgment has usually been impaired for some time, making intervention more urgent.