It only takes one drink to slow your reflexes and impact your attention span. After two drinks your ability to concentrate is impaired. After three you start to begin to experience physical impairments from the alcohol. Four or more can lead to dizziness, vomiting and passing out.
You have heard this all before. In fact, if you are under 50 years of age, you have heard this continually since you were old enough to understand. Sadly, hearing it so often has made many people tune out these important facts and they do not take the seriousness of operating a vehicle under the influence to heart.