Motions to suppress evidence in Michigan OWI cases

A motion to suppress asks the court to keep evidence out of the trial because it was obtained in violation of the law. In Michigan, "evidence obtained in violation of the Fourth Amendment is inadmissible as substantive evidence in criminal proceedings," as a general rule.^[1] The rule also reaches "materials and testimony that are the products or indirect results of an illegal search," known as the fruit of the poisonous tree doctrine, and its purpose "is to deter police misconduct."^[1]

This page explains the exclusionary rule, what an OWI suppression motion can target, Michigan's limits on exclusion, and how the motion is heard. It does not predict whether any motion would be granted; that depends on the facts and the court's findings.

The basic rule and its limits

Warrantless searches and seizures are "unreasonable per se," and evidence seized in violation of the constitutional prohibition "must be excluded from trial," but "several exceptions exist such that a warrant is not always required."^[6] Exclusion is also not automatic once a violation is found. In Lucynski III (2024), the Michigan Supreme Court said that "suppression turns on the culpability of the police and the potential of exclusion to deter wrongful police conduct," and that a seizure based on an officer's unreasonable interpretation of the law warrants exclusion.^[2]

Michigan's good-faith exception

In People v Goldston (2004), the Michigan Supreme Court adopted the good-faith exception: evidence obtained through a defective search warrant is admissible when the executing officer relied on the warrant "in objective good faith."^[3] A warrant may still be so facially deficient that officers could not reasonably presume it valid.^[3]

What an OWI suppression motion can target

Stage	Legal standard	Michigan example
The stop	Articulable and reasonable suspicion of a violation[7]	Lucynski: misreading an unambiguous statute is not a reasonable mistake of law[8]
Prolonging the stop	No extension beyond the stop's mission without new reasonable suspicion[9]
Seizing a parked car	Blocking a car from leaving a driveway can be a seizure[10]	Lucynski III: evidence from the driveway seizure suppressed[2]
Checkpoints	Sobriety checkpoints violate the Michigan Constitution[11]	Sitz (1993)[11]
Probable cause to arrest	PBT must follow the 15-minute deprivation rule[12]	Robe: PBT after about 3 minutes of observation excluded from the probable-cause analysis[13]
Blood draw	No per se exigency from alcohol dissipation; not a search incident to arrest[14][15]	Hyde: for blood from a diabetic driver wrongly told he had to consent, the court rejected the argument that a warrant would inevitably have been obtained[16]
Statements	Miranda applies to custodial interrogation, even for traffic misdemeanors[17]

The stop rules are covered in reasonable suspicion for a traffic stop and parked-car OWI; the arrest in probable cause for an OWI arrest.

Breath and blood tests

The officer's PBT result is admissible to help decide a challenge to the validity of the arrest.^[18] In Robe, the Court of Appeals held that a PBT given in significant violation of the observation rule could not support probable cause, because the violation called into question the accuracy of the result.^[13] On a later appeal, the court reversed a finding that the blood-draw warrant was supported by probable cause without the PBT and remanded for the trial court to decide whether the good-faith exception applied.^[19] See the breath-test observation period.

The natural metabolism of alcohol does not create an automatic emergency for a warrantless blood draw; exigency is decided "case by case based on the totality of the circumstances."^[14] A blood test may not be given as a search incident to a drunk-driving arrest.^[15] In Hyde, the Court of Appeals rejected the argument that blood taken without valid consent would inevitably have been obtained by warrant, warning that this would let the doctrine "engulf[] the warrant requirement."^[16] See search warrants for blood draws.

Warrant affidavits

A blood-test warrant should not be invalidated unless "material misstatements or omissions necessary to the finding of probable cause have been made."^[20] Under Franks v Delaware, a defendant who makes a substantial preliminary showing of a deliberate falsehood or reckless disregard for the truth in the affidavit is entitled to a hearing.^[21] At that hearing the defendant has the burden of showing, by a preponderance of the evidence, that false material was knowingly or recklessly inserted and was necessary to the probable-cause finding.^[21]

Statements

Miranda safeguards apply to custodial interrogation "regardless of the nature or severity of the offense."^[17] A motorist detained for a routine traffic stop "is ordinarily not in custody within the meaning of Miranda," but the safeguards apply once freedom is curtailed to a degree associated with formal arrest.^[22] A challenge to a confession is decided at a Walker hearing held outside the jury, where the prosecution bears the burden of showing admissibility.^[23] See Miranda rights and OWI stops.

Filing and hearing the motion

• Timing. A motion to suppress generally must be made before trial; the court has discretion to hear one during trial but need not allow an untimely motion when the facts were known beforehand.^[4] In district court, the judge may require pretrial motions to be filed and argued no later than the pretrial conference.^[24]
• Hearing. A defendant is generally entitled to an evidentiary hearing on a constitutional challenge, but not where the challenge is insufficient or unsupported by facts.^[4]
• The record. The parties may stipulate that the motion be decided on the preliminary examination transcript.^[5] A ruling at a felony preliminary exam does not stop either party from asking the circuit court to decide the question again.^[25]
• Defendant's testimony. If the defendant testifies at an evidentiary hearing, that testimony is not admissible at trial on guilt or innocence.^[5]
• Review. Findings of fact are reviewed for clear error, and the ultimate ruling de novo.^[5]

Facts for a motion can come from discovery, including police reports, recordings and warrant papers, which the prosecutor must provide on request.^[26] See discovery and video evidence and the evidence in an OWI case.

Related remedies outside the Fourth Amendment

Some exclusion rules come from statute rather than the Constitution. If the prosecution does not fully comply with a written request for chemical test results at least 2 days before trial, the results may not be admitted by the prosecution.^[27] A refusal of a chemical test may be shown only to prove that a test was offered, not as evidence of guilt.^[28] The license consequences of a stop and arrest are decided separately, at an implied-consent hearing if one is requested after a refusal.^[29]