Before you drive, make sure you are comfortable with your physical, mental, and emotional state, your vehicle and the conditions in which you will be driving. If you have doubts about any of them, don't drive.
Your ability to drive can change from one day to the next. Illness, fatigue, prescription and over-the-counter drugs, stress and your mental or emotional state can greatly diminish your ability to operate a motor vehicle. You should consider these factors before you begin driving, and you should not operate a motor vehicle when you are not fit to do so.