Which of the following can affect a driver's ability to drive safely?

Alcohol, some illegal drugs, some prescription medications, and some over-the-counter medications can cause drowsiness, sedation, or impaired coordination, which may impair one's ability to drive. Pep pills and other stimulants can make you nervous, dizzy, or unable to concentrate, and they can affect your vision. If you are unsure of the effects of a particular medication, check the warning label or ask your pharmacist or doctor.