WASHINGTON — Motorists are being convicted of driving under the influence of marijuana based on arbitrary state standards that have no connection to whether the driver was actually impaired, says a study by the nation's largest auto club.
The problem is only growing as more states contemplate legalizing the drug. At least three, and possibly as many as 11 states, will vote this fall on ballot measures to legalize marijuana for medicinal or recreational use, or both. Legislation to legalize the drug has also been introduced in a half-dozen states.
Currently, six states — Colorado, Montana, Nevada, Ohio, Pennsylvania and Washington — have set specific limits in drivers' blood for THC, the chemical in marijuana that makes people high. Marijuana use is legal in those states for either recreational or medicinal purposes, with the exception of Ohio. The laws presume a driver whose THC level exceeds the threshold is impaired. But the study by AAA's safety foundation says the limits have no scientific basis and can result in innocent drivers being convicted, and in guilty drivers being released.
"There is understandably a strong desire by both lawmakers and the public to create legal limits for marijuana impairment in the same manner we do alcohol," said Marshall Doney, AAA's president and CEO. "In the case of marijuana, this approach is flawed and not supported by scientific research."
Another nine states, including some that have legalized marijuana for medical use, have zero-tolerance laws that make the presence of THC or its metabolites in a driver's blood illegal -- despite the fact the substances can linger in the bloodstream for weeks after any impairment has dissipated.