It is difficult to determine how specific drugs affect driving, but we do know that even a small amount of some drugs can be...

It is difficult to determine how specific drugs affect driving, but we do know that even a small amount of some drugs can be very dangerous. Marijuana can slow reaction time or impair the judgment of time and distance. Drivers who have used cocaine or methamphetamine can be aggressive and reckless. Certain kinds of sedatives can cause dizziness and drowsiness.