What Law Enforcement Needs to Know

What Law Enforcement Needs to Know2018-11-29T18:09:58+00:00

What the Recreational Marihuana Law Means for Prosecutors/Law Enforcement in OWI Cases

Prosecutors and law enforcement handling impaired driving cases should be familiar with the Michigan Supreme Court ruling of People v. Koon, 494 Mich 1; 832 NW2d 724 (2013).  This continues to be binding case law in our state.

In People v. Koon, the Court ruled that, “The immunity from prosecution provided under the MMMA to a registered patient who drives with indications of marijuana in his or her system but is not otherwise under the influence of marijuana inescapably conflicts with MCL 257.625(8), which prohibits a person from driving with any amount of marijuana in his or her system. Under the MMMA, all other acts and parts of acts inconsistent with the MMMA do not apply to the medical use of marijuana. Consequently, MCL 257.625(8) does not apply to the medical use of marijuana.”

On November 6, 2018, Michigan voters chose to become a recreational marihuana state by adopting the Michigan Recreational Marihuana Law (MRML).

Like the Michigan Medical Marihuana Act (MMMA), the MRML contains the following language which will take effect in mid-December 2018:

Section 4.1 This act does not authorize: (a) operating, navigating, or being in physical control of any motor vehicle, aircraft, snowmobile, off-road recreational vehicle, or motorboat while under the influence of marihuana;

Section 4.1 5. All other laws inconsistent with this act do not apply to conduct that is permitted by this act.

In light of the language in the MRML, it is important for law enforcement to know what to look for when someone is under the under the influence of ONLY marihuana. Listed below is what officers should be looking for during a roadside investigation to establish probable cause of impairment due to marihuana.


  • Bloodshot, watery eyes
  • Relaxed inhibitions
  • Body tremors
  • Eyelid tremors
  • Impaired perception time/distance
  • Increased appetite
  • Possible paranoia
  • Possible panic attacks
  • Divided attention impairment
  • Odor of marijuana (not always)
  • Debris in mouth and/or on tongue

Standardized Field Sobriety Test (SFST) Indicators:
Impairment will usually be evident on the Walk and Turn (WAT) and/or One-Leg Stand (OLS).  Marihuana alone will usually not cause any Horizontal Gaze Nystagmus (HGN), but a subject may have difficulty holding his or her head still due to divided attention issues.  Vertical Gaze Nystagmus (VGN) will not be present.   

Walk and Turn:
There are eight clues on this test that were studied and validated for the .08  percent breath alcohol concentration (BAC).  However, they are extremely useful for disclosing drug impairment as well.  The eight clues are easy to remember through the following acronym:

In the following order, subjects sometimes lose their Balance during instructions.  Sometimes they Start walking too soon.  Sometimes they Stop while walking.  Sometimes they step Offline.  Sometimes they take the Wrong number of steps.  Sometimes they miss touching Heel to toe by more than half an inch.  Sometimes they raise their Arms more than six inches from their sides for balance.  Sometimes they Turn improperly.  In addition, general, non-studied indicators of impairment frequently manifest themselves as well including but not limited to the following: failing to count each step out loud, failing to watch feet while walking, and body tremors.

One-Leg Stand:
This test contains four studied, validated clues for alcohol, but may also be useful in establishing impairment due to marihuana.  An easy way to remember the clues is with the following acronym:

Sometimes subjects put their foot Down while balancing.  Sometimes they raise their Arms over six inches from their body for balance.  Sometimes they Sway while balancing.  Sometimes they Hop.  General indicators of impairment frequently occur as well with the OLS including but not limited to the following: not looking at the raised foot while balancing, jumbled count or no count, body tremors, and an unusually fast or slow count.

As with the WAT, officers need to make sure they are always in “substantial compliance” with the standards set forth by the National Highway Traffic Safety Administration (NHTSA) when administering the SFSTs.  A test that falls short of being administered in “substantial compliance” may not be admitted at trial as evidence of impairment.

Please take the time to review your SFSTs and be as sharp as you can on them.  If you commit these tests to your memory banks, they will be there when you really need them.  Also, officers are encouraged to incorporate the Modified Romberg Balance Test and the Lack of Convergence (LOC) test into all OWI investigations.  Both tests are very useful for helping establish probable cause to arrest in OWI cases.

Lastly, in a marihuana-impairment driving case, it is imperative that blood results come back with THC in the subject’s blood.  People v. Feezel, 486 Mich 184; 783 NW2d 67 (2010).

For more information on these cases, statutes and PAAM training programs, contact your Traffic Safety Resource Prosecutors, Kenneth Stecker and Kinga Canike, at (517) 334-6060 or email at steckerk@michigan.gov and canikek@michigan.gov.  Please consult your local prosecutor before adopting practices suggested by reports in this article.  The court decisions in this article are reported to help you keep up with trends in the law.  Discuss your practices that relate to these statutes and cases with your commanding officers, police legal advisors, and the prosecuting attorney before changing your practices in reliance on a reported court decision or legislative changes.

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