Zero Tolerant “Drugged Driving” Limits Unconstitutional, German Supreme Court Says

Berlin, Germany: A national law that defined motorists with any detectable level of drugs or marijuana (THC) in their blood as impaired per se has been struck down by the German Supreme Court.

The Court determined that the prosecution of persons who test positive for trace levels of drugs, but are not otherwise impaired, was not the legislative intent of the law. However, the Court did not clarify the law to establish set guidelines at which drivers who test positive for drugs in the blood can be considered legally impaired.

Similar “zero tolerance” drugged driving laws classifying motorists who test positive for any amount of illicit drugs or drug metabolites (non-psychoactive compounds produced from the chemical changes of a drug in the body) in their bodily fluids (blood, saliva, sweat and/or urine) as criminally impaired have been enacted in eleven US states: Arizona, Georgia, Illinois, Indiana, Iowa, Michigan, Minnesota, Pennsylvania, Rhode Island, Utah, and Wisconsin.

Though no scientific consensus yet exists specifying per se impairment levels for marijuana, drivers with THC levels in their blood below 5ng/ml are not associated with elevated risks of having a traffic accident in culpability surveys.

Speaking last August at the 17th International Conference on Alcohol, Drugs and Traffic Safety (ICADTS) in Glasgow, Scotland, presenters from an international working panel of physicians, forensic toxicologists and traffic scientists, led by Drs. Franjo Grotenhermen of Germany’s nova-Institut and Gunter Berghaus of the University of Cologne, said: “Commonly consumed doses of THC may cause maximum psychomotor impairment in some behavioral areas comparable to that equivalent to a BAC of above 0.08 percent. … [However,] relevant acute effects typically subside within 3-4 hours after smoking. … According to culpability studies, THC levels in blood serum below 5 ng/ml were not associated with an elevated accident risk. Even a THC serum level of between 5 and 10 ng/ml may not be associated with an above normal accident risk. [Therefore,] unless they are under the acute influence of the drug, both frequent and infrequent users of cannabis do not seem to have a higher accident risk than non-users.”

For more information, please contact either Allen St. Pierre or Paul Armentano of NORML at (202) 483-5500. For a summary of European DUID laws, please visit: