The very first effect of even a small amount of alcohol on a person’s safe driving ability is to reduce his or her:

Good judgment

Explanation:

Alcohol and driving is a combination that never works. In 2016, 28% of deaths from traffic accidents in the world were attributed to alcohol consumption.

Even small quantities of alcoholic beverages affect the driving ability of drivers. Even a small amount of alcohol can affect a driver's good judgment and this causes dangerous situations such as slower than normal reactions and a lack of awareness of the speed of the car itself and other vehicles, which can cause fatal accidents.