Explanation:
"You never know what will happen. The same drugs and the same amounts of drugs, will affect each person differently. Also, the same drug can affect you more at one time than another. Weight, emotional state, heart and breathing rate, food intake, amount of sleep, tolerance for a drug and other factors, can all influence the way you react to drugs. Even a small amount of alcohol or drugs will reduce your ability to judge a driving situation, decide what to do and act quickly."