Probable Cause for an OWI Arrest in Michigan

Police may arrest a person for operating while intoxicated (OWI) when they have probable cause: facts and circumstances, known to the officers from reasonably trustworthy information at the moment of arrest, sufficient to warrant a prudent person in believing that the person committed or was committing an offense. Michigan courts decide this on the totality of the circumstances.^[1] Probable cause is a higher standard than the reasonable suspicion needed to make the traffic stop in the first place.^[7]

Probable cause compared with other standards

Standard	What it allows in an OWI case
Reasonable suspicion	A traffic stop: "a lesser showing than probable cause" but more than a hunch.[7]
Reasonable cause under MCL 257.625a(2)	Requiring a roadside preliminary breath test (PBT).[8]
Probable cause (reasonable cause in the arrest statutes)	An arrest.[1][9]
Reasonable grounds under MCL 257.625a(6)(d)	Requesting the evidential breath, blood or urine test after arrest.[10]
Probable cause at a preliminary examination	Binding a felony OWI case over to circuit court.[11]

"Reasonable cause" and "probable cause" mean the same thing

Michigan's arrest statutes use the words "reasonable cause." According to the 1989 Staff Comment to MCR 6.102, reasonable cause and probable cause are equivalent, and probable cause is the preferred term.^[9] This page uses both, following the wording of each source.

The OWI arrest powers in the statutes

A peace officer may arrest without a warrant for a misdemeanor committed in the officer's presence, and on reasonable cause for a misdemeanor punishable by more than 92 days or a felony.^[12] On top of those general rules, the Vehicle Code and the Code of Criminal Procedure give officers OWI-specific arrest powers:

• After a crash. An officer may arrest without a warrant a person the officer has reasonable cause to believe was the operator of a vehicle involved in a Michigan accident and was operating in violation of section 625, even though the officer did not see the driving.^[2]
• Driver's seat, car in the roadway. An officer may arrest a person found in the driver's seat of a vehicle parked or stopped on a highway or street if any part of the vehicle intrudes into the roadway and the officer has reasonable cause to believe the person was operating while intoxicated.^[3]
• The parallel criminal-procedure provisions. MCL 764.15(1)(h) and (i) repeat these two powers for violations of section 625(1), (3), (6) or (7) and the commercial-vehicle offense in section 625m.^[13]

OWI offenses are excluded from the rule that requires police to release certain misdemeanor arrestees on an appearance ticket, and an arrestee who is under the influence is held until in a proper condition to be released or until the next session of court.^[14][15] The guide to OWI investigations after a crash covers crash cases in more detail, and sitting in a parked car covers the driver's-seat cases.

What can add up to probable cause

No single checklist decides probable cause, because courts look at the totality of the circumstances.^[1] The sources in this guide address several pieces of evidence officers rely on:

• Odor of intoxicants. A strong odor can, standing alone, support reasonable suspicion that the motorist was driving under the influence, but the courts note it does not necessarily mean the alcohol level exceeds the legal limit.^[16]
• Field sobriety tests. These are NHTSA-validated tests given in substantial compliance with NHTSA standards, and NHTSA says they are a tool for seeing visible signs of impairment, not pass/fail tests.^[17][18]
• The PBT. An officer may arrest a person based in whole or in part on the PBT result.^[4]
• Signs of impairment without bad driving. For OWVI, the Court of Appeals has said the statute does not require proof of impaired driving such as weaving, as the guide on operating while visibly impaired explains.^[19]

The State Police state that drivers can be arrested at any alcohol level if an officer believes they are impaired.^[20]

When the PBT cannot be counted: People v Robe

Because the PBT can support an arrest, how it was given matters. Under the current State Police rule, a PBT may be given only by a certified operator after the operator determines the person has not smoked, regurgitated or put anything in the mouth for at least 15 minutes.^[21] In People v Robe (2021), decided under the earlier version of the rule, the officer observed the driver for only about three minutes and no one else observed him for the rest of the period. The Court of Appeals held the PBT had to be excluded from the probable-cause analysis because the rule violation was significant and called the result's accuracy into question.^[5]

On a later appeal in 2022, in an unpublished opinion, the Court of Appeals reversed the trial court's finding that the blood-draw warrant was supported by probable cause without the PBT and sent the case back to decide whether the good-faith exception applied.^[22] The observation rule is explained further in the 15-minute observation rule and the PBT guide.

Probable cause and blood warrants

If a driver refuses the evidential test, police may seek a court order (a search warrant) for a test.^[23] The warrant itself must rest on probable cause. A warrant for chemical testing should not be invalidated unless material misstatements or omissions necessary to the finding of probable cause were made (People v Czuprynski).^[24] See search warrants for blood.

How probable cause is challenged

1. In the criminal case. For a warrantless arrest, the prosecution has the burden of establishing that it was supported by probable cause.^[6] Quoting People v Lewis (1987), the Evidence Benchbook states that without a warrant or probable cause the detention is illegal, and evidence obtained as a result, or statements made while unlawfully detained, must be suppressed.^[25] Whether an exception such as good faith applies can also be litigated, as the Robe remand shows.^[22] The procedure is covered in motions to suppress.
2. At the implied-consent hearing. After a refusal, the Secretary of State hearing decides four issues, the first being whether the officer had reasonable grounds to believe the person committed one of the listed crimes.^[26] See the implied consent hearing.
3. At a felony preliminary examination. The question there is different: whether there is probable cause that a felony was committed and that the defendant committed it, so the case can be bound over.^[11] The arrest standard and the bindover standard are distinctly different, and a finding that the evidence did not support bindover does not by itself make the arrest invalid (People v Cohen).^[27]

Common misunderstandings

• "No probable cause means automatic dismissal." Suppression is a ruling on evidence; what happens to the case afterward depends on what other evidence remains, and practice varies by court.
• "Passing the PBT means no arrest." An arrest rests on the totality of the circumstances, and OWI can be shown by being under the influence, not only by a number.^[1][28]
• "Failing the PBT proves guilt." In an OWI prosecution, PBT results are admissible only for limited purposes, such as deciding a challenge to the validity of the arrest.^[29]