Driving under the influence (DUI) includes both driving under the influence of alcohol, as well as driving under the influence of any narcotic drug, any self-administered intoxicant or drug or substance which impairs the ability to drive/operate a motor vehicle, engine or train safely. That description also includes impairment by medications legally prescribed to you if the medication impairs your driving. Illegal substances which can be the basis for DUI include but are not limited to cocaine, marijuana, methamphetamine, phencyclidine (PCP) and methylenedioxymethamphetamine (MOMA ecstasy).
In Virginia, if the vehicle is in motion, it can provide probable cause for an officer to make the stop. Also, if your vehicle’s engine is running, but the car is not in motion, or if you are in the driver’s seat at the time of the stop, that also provides probable cause. Probable cause gives the officer observing the behavior the authority to make the stop.