A proposed DUI bill in Colorado being discussed later today would set the blood-THC limit at 5 nanograms of active THC for every milliliter of blood. The key here is that it's active, as latent inactive THC levels can linger in the system for weeks after use causing no actual impairment.
But state law doesn't always recognize these differences, as seen in an Arizona court ruling. It establishes that people there can be found guilty of driving under the influence whether they're impaired or not -- and even if they've got negligible amounts of THC in their system.
As noted by Phillip Smith in a post written for his website StopTheDrugWar.org, the Arizona Court of Appeals was asked to weigh in on a case involving Hrach Shilgevorkyan, who was pulled over in December 2010 for speeding and unsafe lane usage. According to the Court of Appeals opinion, issued last week and on view below in its entirety, Shilgevorkyan subsequently consented to a blood test that showed an eight nanogram-per-blood-milliliter concentration of Carboxy-Tetrahyrocannabinol, or Carboxy-THC.
Note that the Colorado proposal related to driving under the influence of drugs would set a five nanogram THC standard.
The deputy who stopped Shilgevorkyan subsequently filed an Arizona traffic ticket charging him with two counts of driving under the influence, referencing a state statute that makes it "unlawful for a person to drive or be in actual physical control of a vehicle" while there is a banned drug or "its metabolite" in its system.
Shilgevorkyan moved to dismiss the complaint, because Carboxy-THC is marijuana's inactive ingredient, as differentiated by Hydroxy-Tetrahyrocannabinol, or Hydroxy-THC, the metabolite that would indicate impairment. As such, he maintained, the presence of Carboxy-THC didn't prove he was impaired.