DWI Traffic Stops in Minnesota: Legal vs. Illegal Police Conduct

DWI arrests in Minnesota frequently begin with a  traffic stop made by a police officer or state patrol trooper.  After the stop there is generally a sequence of actions taken by the officer if they suspect the driver has violated Minnesota DWI law. There are of course, legal and illegal (constitutional and unconstitutional) ways of both initiating a traffic stop and conducting subsequent questioning, testing, etc.  The following is a brief overview of the constitutional issues surrounding typical DWI traffic stop in Minnesota.

  1. The Traffic Stop:  An officer can make a brief investigatory traffic stop without violating the constitutional prohibition against “unreasonable searches and seizures” (afforded by both the Fourth Amendment of the U.S. Constitution and Article 1, Sec. 10 of the Minnesota State Constitution) if they have “reasonable, articulable suspicion” of criminal activity.  An officer’s observation of a traffic violation, even if insignificant, can provide the officer with an objective and reasonable basis to make a legal traffic stop. Typical traffic violations which provide a basis for a stop include speeding, not signaling a lane change, and equipment violations.
  2. Initial Questioning:  After an officer has made an initial stop, they generally ask the driver a series of questions (e.g. “Are you aware of why I pulled you over?”) and request a driver’s license and vehicle registration.
  3. Field Sobriety Testing:  During the initial questioning in a DWI traffic stop, the officer will often make observations of alcohol use and/or intoxication.  These observations frequently include slurred speech, glassy/watery eyes, (strong) odor of alcohol, slow reaction time, and the driver admitting alcohol use prior to driving. If the officer does make these observations, they can provide the basis (reasonable, articulable suspicion that the driver has violated the DWI law) to legally conduct a series of field sobriety tests.  The standard field sobriety tests (SFST) include a series of three tests:  the walk and turn test (WAT); the  one leg stand (balance) test (OLS); and the horizontal gaze nystagmus test (HGN).  There are also non-standardized field sobriety tests that the officer may have the driver perform including: the Romberg  (Balance) Test; counting backwards; reciting the alphabet etc.  Failure of the  field sobriety tests can be used by the officer to establish probable cause to arrest the driver for DWI.
  4. Portable Breath Test (PBT): The officer will typically request  a portable breathalyzer test (PBT) from the driver if they fail the field sobriety tests.  The legal basis to request the PBT, however, is the same as for the request for field sobriety testing: “reasonable, articulable suspicicion” that the driver has violated Minnesota DWI law.  This can include the failure of one or more of the field sobriety tests, admissions from the driver of alcohol use, and/or other observations of possible alcohol use and/or intoxication (e.g. glassy eyes, strong odor of alcohol etc.). In addition, like the field sobriety tests, a PBT failure can be used by the officer to establish probable cause to arrest a driver for DWI.
  5. Arrest:  An officer must have probable cause to make a legal arrest of a driver for DWI.  Probable cause in Minnesota exists if a person of ordinary care and prudence holds an “honest and strong” suspicion that arrested party is guilty of a crime.  Probable cause is more than mere suspicion.  The officer can establish probable cause to make a legal arrest with a combination of observations of alcohol use and/or intoxication, statements by the driver indicating alcohol use and/or intoxication, failure of one or more of the field sobriety tests, and/or failure of the PBT test.

What Can Be Done About Illegal Conduct?

The Fourth Amendment of the U.S. Constitution and Article 1, Sec. 10 of the Minnesota Consitution protects individuals against unreasonable searches and seizures.  The remedy for an illegal search and seizure is suppression of the evidence obtained as a result of the illegal search and seizure.

In a typical DWI case as described above, therefore, if the officer illegally made the initial traffic stop or otherwise illegally conducted the questioning, testing and/or arrest, the driver can move the court to suppress evidence that was obtained as a result of that illegal search or seizure.  In Minnesota, this is done at what is know as a “Rasmussen Hearing.”  If the Motion for suppression is granted, the prosecution cannot use the illegally obtained evidence at trial.  This can obviously have a huge impact on the case.  A very positive impact for the defense, and very negative impact for the prosecution.  In fact, the prosecution may dismiss the case and/or offer a very favorable plea agreement  in the event of suppression.

Legal Disclaimer

The following is for informational purposes only and does not constitute legal advice.  Although the following information is deemed accurate and current, statutory and case law change frequently and the following information should not be relied upon as authoritative.

About the Author

Thomas A. Wilson | Attorney at LawThomas A. Wilson is a practicing Minnesota criminal law attorney. Mr. Wilson is owner of Wilson Law Firm P.L.L.C., located in St. Paul, Minnesota.View all posts by Thomas A. Wilson | Attorney at Law →