Driving under the influence (DUI), driving while intoxicated (DWI), drunken driving, drunk driving, drink driving, operating under the influence, drinking and driving, or impaired driving is the act of driving a motor vehicle with blood levels of alcohol in excess of a legal limit (“Blood Alcohol Content”, or “BAC”). Similar regulations cover driving or operating certain types of machinery while affected by drinking alcohol or taking other drugs. This is a criminal offense in most countries. Convictions do not necessarily involve actual driving of the vehicle.