The prosecution of DUI charges in Colorado continues to stoke disagreement regarding marijuana and controlled substance enforcement policies. One legislator recently introduced a controversial bill that would allow police to arrest drivers based on a "presumption" of driving under the influence of marijuana or controlled drugs. Currently, the DUI limit for THC in the operator's blood is 5 nanograms.
If the legislation passes, the 5 nanogram provision would necessarily be repealed. The new law would allow the police to determine if the driver is impaired, although the exact ways in which that may be determined is unclear. If there is also a finding of a "measurable amount" of a drug or controlled substance other than alcohol in the driver's blood within four hours of driving, the police may arrest for DUI.
Many from both sides of the controversy agree that the nanograms of THC in the operator's blood is not necessarily an accurate measure of the driver's ability to drive. A driver with 5 nanograms may not be impaired at all, according to the representative sponsoring the bill. However, it appears that the proposed law could present various practical and constitutional drawbacks that make it problematic. For example, the finding of any "measurable" amount of a drug in one's blood is arguably too broad and ambiguous a standard to support a constitutional arrest for DUI.
The representative who presented the bill is also a deputy district attorney in Eagle County who has prosecuted hundreds of DUI cases, which also gives rise to potential claims of a conflict of interest. Opponents already point to an existing provision of the Colorado Constitution that prohibits a legislator from also serving in "any civil office" in Colorado. At this point, the usual process of debate will follow, and the success of the bill will turn on whether a substantial number of other legislators give serious approval to the proposal.