This is an important question and nowhere near as obvious as one would think.
The reason that it is important is that the Fourth Amendment to the United States Constitution requires the police to have either a warrant or probable cause to arrest you (though they only need “reasonable suspicion” to pull you over.
Since the officer who pulls you over at 2 in the morning is almost certainly not going to have a warrant for your arrest or a search warrant for your blood alcohol level, he or she is going to need probable cause to arrest you and take you back to the station and ask you to blow into the machine.
But sometimes, whether the officer had probable cause to arrest you may be a dicey question for the prosecutor. Sometimes, if the arrest happens too fast, the court may conclude that there was no probable cause at the time of the arrest. Sometimes though, things happen just after the arrest that make probable cause a cinch, but since they happened after the arrest, they can’t be considered by the Court in determining whether or not the officer had probable cause.
In these cases, prosecutors will start making some pretty strange arguments about when the arrest has occurred. They will argue that even though you were handcuffed and put in the back of the police car, that this still was not an arrest. The prosecutor will argue that the only reason that the police officer did this was to keep you safe since you were stumbling around and you might wander into the roadway and be struck by oncoming traffic.
Do courts buy this sort of argument from police officers? Some do.
In State v. Quesenberry, the suspect had been handcuffed and placed in the back of a local police cruiser to await the arrival of a highway patrol officer. The Seventh Appellate District Court held that the suspect had not been arrested, reasoning that:
Applying the law to the facts of the present case, it appears that Officer Flanagan had not intended to arrest appellant when he handcuffed him and placed him in the back of the cruiser. Rather, Officer Flanagan’s actions were taken in furtherance of his and appellant’s safety as well as in furtherance of his investigative stop. . .
Due to the severe nature of the crash, appellant’s diminished motor and coordinative skills, and the high traffic area where the crash was located, there was a chance that appellant might injure himself or the other officers who were conducting the investigation. Under the totality of the facts and circumstances in the case at bar, it appears that Officer Flanagan’s act of handcuffing appellant and placing him into the back of the police cruiser did not convert the investigative stop into an arrest.
So being handcuffed and put in the back of a police car may not be an arrest in the state of Ohio if the prosecutor didn’t yet have probable cause at that point.
In the case of State v. Stanford, (and it should be noted that the case caption has the defendant’s name wrong), a police officer grabbed a defendant’s wrist and told him he was under arrest after observing him with a bottle of beer (the problem here being that open container violations are minor misdemeanors for which one cannot be arrested).
The trial court held that this was an arrest, and suppressed the evidence of cocaine that was later found when the officers searched the suspect. But the prosecutor appealed, arguing that the suspect had not been arrested until moments later when he briefly fled from the police and was recaptured (there is your probable cause showing up).
The First Appellate District Court in Hamilton County found that the suspect was not under arrest when the officer grabbed his wrist and told him that he was under arrest. The Court reasoned that:
Officer Howard testified that he never had the intent to arrest Stafford for an open-container violation, but merely wanted to issue a citation. Further, Officer Howard testified that he only told Stafford that he was “under arrest” because “it’s the quickest way to let someone know that they are being temporarily detained, they do not have the right to leave.” He also testified that he grabbed Stafford’s wrist because Stafford was fidgety and the officer was concerned for his safety.
But there are situations where the prosecutor wants you to be under arrest sooner rather than later. For instance, in the case of State v. Qualey, a drunk driving suspect argued that he had never been formally placed under arrest so his breath test must be suppressed. In order for the ALS suspension to kick in under Ohio’s Implied Consent law, you must first be placed under arrest, and then requested to take the BAC test. The police officer said only to Mr. Qualey “You are under arrest” but never handcuffed him. Further, the officer let Mr. Qualey go with a citation and summons to appear in court after the test was administered.
The Second Appellate District Court in Montgomery County held that Mr. Qualey had indeed been arrested, in that:
An arrest can occur under either of two circumstances. This first of those circumstances is a formal arrest where the officer explicitly and unequivocally informs the subject that he or she is under arrest. . .
We find that Officer Moore formally arrested Qualey by expressly and unequivocally informing him that he was under arrest for the charge of driving under the influence of alcohol and by reading Qualey his Miranda rights.
So the prosecutor gets to have it both ways, just so long as it results in a conviction. In Stafford telling the suspect he is under arrest does not necessarily make it one, but in Qualey, if you tell the suspect he is under arrest, then he is.