DUID
Template:Globalize DUID is the acronym that stands for Driving Under the Influence of Drugs. It is akin to DUI or DWI for driving under the influence of alcohol or driving while intoxicated.
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 the United States). 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 may be only the remnants of drug use in days or weeks past. However testing equipment is generally calibrated to only pick up recent typically impairing usage and to not detect more historic drug use.
The laws were passed in response to the problems reported by prosecutors who sometimes found it difficult to prove that a driver was impaired from using a controlled substance. Practical difficulties included the transient effects of some drugs wearing off before Police or Drs had a chance to assess many suspects for impairment. These laws make their cases much easier to win because they only have to prove the presence of a controlled substance in the blood or urine, without a prescription. The logic is that the trade off of more efficient prosecutions with wide benefit to road safety is worth the potential conviction or more often non criminal sanction of a driver who may have a slim chance of being unimpaired, because the driver was already violating the law by using a controlled substance without a prescription.