Reason Magazine calls bullshit on CBS4 and their attempt to justify a five nanogram marijuana driving limit in Colorado:
CBS4 concedes that one volunteer, Jeff Underberg, "drove very cautiously" with a THC level four times the legal limit after smoking his first three-tenths of a gram. "While his driving was slow," KIRO reported, "it was still acceptable." According to the driving instructor who accompanied Underberg, "He did real well." But CBS4 inaccurately portrays the performance of the other two subjects. The heaviest cannabis consumer, a medical marijuana user named Addy Norton, did not fail the driving test until after consuming a total of 1.4 grams of pot and achieving a THC level of 58.8 nanograms, almost 12 times Washington's legal limit. Yet CBS4 shows her giggling at the wheel and knocking over a traffic cone, implying that she was impaired throughout the experiment. Another subject, Dylan Evans, smoked three-tenths of a gram, reaching a THC level of 26 nanograms, but still was "doing fine behind the wheel," according to the KIRO report. CBS4 falsely claims that Evans "drove off the course" at this stage, adding that "at one point the driving instructor had to grab the wheel," which did not happen until after the third round of pot smoking.
The impression left by the CBS4 story is so misleading that after watching it Westword blogger Michael Roberts, no fan of the five-nanogram standard, wrote that "the KIRO report shows three volunteers who smoke, then climb into vehicles and attempt to navigate a driving course—and mostly fail badly, by either going far too slow or swerving into cones set up to simulate roadways." In fact, all three subjects performed well after their first round of smoking, providing further evidence that the DUID bill moving through the Colorado legislature is based on a mistaken premise.