Opponents to California's Proposition 19, otherwise known as the Regulate, Control and Tax Cannabis Act of 2010, argue that if the measure passes on November 2, 2010, the roads will become more dangerous. USA Today quotes No on Proposition 19 spokesman Roger Salazar as saying "there won't be anything to stop anyone from legally finishing off a couple joints before getting behind the wheel."
Proponents point to the provisions in the law upholding current laws prohibiting driving under the influence, but Salazar's group notes a lack of clarity. While the proposal has provisions for the establishment of restrictions, opponents argue that there are no actual standards to determine impairment by marijuana like there is for blood-alcohol concentration.
Law or no, there currently isn't a way to stop clandestine cannabis use prior to driving, and police departments are burning tax revenue to enforce current drug laws. Federal drug laws remain in place, however, and will be in direct opposition to Proposition 19 if voters approve it. The uproar may be a new wrinkle to the Reefer Madness argument, though voters eying new sources of tax revenue may find the monetary potential more compelling.