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Supreme Court’s Ruling on Blood Tests: Implications for Colorado’s DUI Laws

The United States Supreme Court has made a significant ruling that has far-reaching implications for Colorado’s DUI laws. On June 23, 2016, the Supreme Court handed down a decision stating that police officers cannot conduct blood tests on suspected drunk drivers without first obtaining a warrant. This ruling raises questions about Colorado’s existing Express Consent law, which requires drivers to agree to blood or breath tests when stopped on suspicion of DUI.

Express Consent and Its Implications

In Colorado, the Express Consent law dictates that obtaining a driver’s license implicitly signifies the individual’s consent to undergo blood or breath tests when pulled over by an officer on suspicion of DUI. However, the recent Supreme Court decision challenges the practice of conducting blood tests without a warrant. As a result, Colorado may need to reassess and revise the Express Consent rule to align it with this new legal precedent.

Impact on DUI-D Arrests

Beyond its effect on traditional DUI cases, this Supreme Court ruling may have significant implications for DUI-D (Driving Under the Influence of Drugs) arrests. Currently, there is no breath test available to measure marijuana impairment accurately. Therefore, the only viable option to assess a person’s marijuana level is by drawing blood. With the Supreme Court’s decision requiring a warrant for blood tests, individuals with marijuana in their system may find themselves protected from unjust DUI-D charges.

The significance of this protection becomes apparent when considering the limited scientific consensus on the relationship between marijuana blood levels and impairment. As research in this area remains inconclusive, the ruling offers potential safeguards for drivers who may be wrongly accused of DUI-D offenses.

Exploring Alternatives: Saliva Tests

While the recent Supreme Court decision explicitly addresses blood tests, it does not directly discuss saliva tests for assessing impairment due to marijuana use. Some voices within the field of law enforcement and public policy have proposed the use of saliva tests as an alternative. These tests could potentially offer a non-invasive and more efficient method for determining marijuana impairment.


In conclusion, the Supreme Court’s ruling has cast a spotlight on Colorado’s DUI laws, particularly the Express Consent rule, and its potential impact on DUI-D cases. As legal dynamics evolve in response to this ruling, it becomes crucial for individuals facing DUI or DUI-D charges to seek guidance and representation from experienced legal professionals. Thomas & Ahnell, LLC, is a law firm specializing in alcohol and drug-related driving offenses in Colorado, offering expert legal counsel to those navigating the complexities of these cases.

Do you have further questions or concerns? Call us or contact the attorneys at Thomas & Ahnell, LLC, and we will be happy to help.

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