A new Colorado law enacted late last year created another weapon for prosecutors to use in seeking convictions for driving under the influence of marijuana cases—a legal inference of 5 nanograms for THC. This law now instructs judges to inform juries that they may infer drug intoxication from a test result of 5 nanograms or more of active THC (the psychoactive element in marijuana) per milliliter of blood.
Colorado Revised Statute section 42-4-1301 contains the Driving Under the Influence (DUI) or Driving While Ability Impaired (DWAI) elements, and both treat alcohol and drugs the same. This means a person can be convicted of the same charge regardless of whether the alleged impairment was caused by alcohol or any prescription or non-prescription drug. Under the State’s DUI laws, marijuana has always been treated the same as prescription pills, alcohol, or any other substance that can impair a person’s ability to safely operate a vehicle.
Legislators say this new 5ng addition creates a “permissive inference” in the courtroom that anyone driving a vehicle with five or more nanograms per milliliter of blood is guilty of driving under the influence of drugs. Critics, such as Denver DUI attorney Jay Tiftickjian, says this law allows the prosecutors to circumvent challenges to the lack of any science behind this limit and legally obtain convictions for drivers why may not have been impaired. Defendant’s must now be prepared to present conclusive evidence to persuade the judge or jury that they were not under the influence despite the blood test result. It shifts the burden of proof to defendants, which is and always has been unconstitutional under the United States Constitution, and requires the accused to spend thousands of dollars on an adequate defense, including independent drug testing, securing expert witnesses for trial, and litigating against a legal limit that has no foundation in science.
Many valid reasons exist for the criticism of the 5 nanogram delta-9 THC inference, or any inference for that matter, for marijuana intoxication. Unlike alcohol, where there are solid scientific studies to represent a correlation between blood alcohol concentration (BAC) and intoxication, measurable peak THC levels in the blood do not necessarily correlate with impairment. A person who smokes marijuana will experience the impairing effects in about 20 to 40 minutes, and the “high” rapidly dissipates around 60 minutes to 2.5 hours later—depending upon the person. However, delta-9 THC in blood will spike within the first fifteen minutes and generally fall below 5 ng within 3 hours. (Armentano, Paul, Should Per Se Limits Be Imposed for Cannabis? Equating Cannabinoid Blood Concentrations with Actual Driver Impairment: Practical Limitations and Concerns, Humboldt Journal of Social Relations, Issue 35, 2013.) Even more disturbing is that studies have found that some chronic users can have active delta-9 THC present in their blood for days after ingestion, well past when the impairing effects wear off. (Karschner et al., 2009. Do Delta- 9-tetrahydrocannabinol concentrations indicate recent use in chronic cannabis users? Addiction, 104: 2041-2048 (2009).
About the author: Jay Tiftickjian is widely considered one of the best DUI attorneys in Colorado. He was named “Barrister’s Best DUI Lawyer” by Colorado’s official bar journal, Law Week Colorado in 2012 and 2013, was voted “People’s Choice—Best DUI Lawyer” in 2013, and is Preeminent AV® Rated by Martindale-Hubbell. He has written numerous books on DUI and drug defense, including Colorado DUI Defense: The Law and Practice. Mr. Tiftickjian is president of Tiftickjian Law Firm PC, which represents clients out of the firm’s offices in Denver and Aspen.