Drug-impaired driving

Drug-impaired driving, or drug driving, in the context of its legal definition, is the act of driving a motor vehicle while under the influence of an impairing substance. DUID, or Driving Under the Influence of Drugs, is prohibited in many countries. Several American states and European countries now have "per se" DUID laws that presume a driver is impaired if they are found to have any detectable quantity of controlled substances in their body while operating an automobile and that the driver has no doctor's prescription for the substance. This is similar to the "per se" DUI/DWI laws that presume a driver is impaired when their blood alcohol content is above a certain level (currently 0.08% in most of the United States and 0.05% in Utah). There is some controversy with "per se" DUID laws in that a driver with any detectable quantity of controlled substances may not in fact be impaired and the detectable quantity in blood or sweat may be only the remnants of drug use in days or weeks past. It is against road traffic safety. Research on factors associated with engaging in DUID is receiving increasing attention to develop more effective countermeasures.