So I came across this article: When a Cop Knocks on the Window, Just Drive Away (in Wisconsin)

Earlier this month, the state's Supreme Court ruled that a tap on the glass does not in and of itself give people reason to assume they've been detained, so they're free to go about their business.

Justice David T. Prosser (speaking for the majority):

Although we acknowledge that this is a close case, we conclude that a law enforcement officer's knock on a car window does not by itself constitute a show of authority sufficient to give rise to the belief in a reasonable person that the person is not free to leave.

Does this mean that you can really just drive away?

3 Answers 3


In this case the car being knocked upon was not being pulled over.

Deputy Small pulled into the parking lot and parked his marked squad car behind Vogt's vehicle a little off to the driver's side. The squad car's headlights were on, but its red and blue emergency lights were not. Vogt's car was running and had its lights on as well. Deputy Small said at the suppression hearing that he was not blocking the car and that the driver could have left, although Daniel Vogt later disagreed.

Deputy Small got out of his squad car and walked up to Vogt's window. He was in full uniform and had a pistol in his side holster. There were two people in the vehicle: Vogt in the driver's seat and Kimberly Russell (Russell) in the passenger's seat. Deputy Small testified at the trial that he rapped on the window but could not recall if the knock was hard or soft.3 He also said that he motioned for Vogt to roll down the window and that if Vogt had ignored him and driven away, Deputy Small would have let him go because he "had nothing to stop him for."

In other words, even the cop agrees that he could not have taken any action against the driver in this case if the driver just drove away, because there was no violation of any law as far as the cop knew when the cop knocked.

County of Grant v. Daniel A. Vogt

This does not mean that if a cop pulls you over with his/her emergency lights and/or siren on that it's ok to drive away.

But if the cop gives no other indication that you should stop or stay, it does seem just a knock on your window is not reason enough for you to need to stay put in Wisconsin.

As a practical matter:

  1. Don't drink and drive.

  2. If you don't have anything to hide, obviously just roll down the window and chat with the officer. Why piss-off the officer and encourage him to give you a ticket or worse?

  3. If an officer knocks on your window and you really don't want to roll down the window, yell "Am I free to go?" to make the office commit to whether he believes there is probable cause to detain you. (see Rights During a Police encounter: 4. Determine if You Can Leave) If you just drive away, you risk the officer being untruthful and alleging that you failed to comply with Wisconsin section 346.04 Obedience to traffic officers.

  4. Even if you do drive away, the officer could follow you and there are so many reasons for the officer to pull you over: allegedly swerving, a couple miles per hour over the speed limit, etc. that it is doubtful you will get very far.

  • 19
    Re: "even the cop agrees that he could not have taken any action against the driver in this case if the driver just drove away": Of course, the cop made this claim only because it suited his desired outcome; if the driver had just driven away, then the cop would have pursued him, and modified his claim accordingly.
    – ruakh
    May 23, 2015 at 6:55
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    @ruakh Your comment doesn't add anything to the answer. May 23, 2015 at 17:23
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    @DJClayworth: OK, then let me more explicit: you should be skeptical of this ruling. The purpose of this ruling was probably to benefit the cop; in a superficially-similar situation where the ruling would instead benefit you, you would be wise not to rely on the same ruling happening again. The court system is not a simple computer program, where the same inputs give the same outputs; it's a real-world human system, where small nuances in the input drive large categorical changes in the output. Stare decisis mitigates this only partially.
    – ruakh
    May 23, 2015 at 17:50
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    @ruakh I appreciate your first comment, but this comment "The purpose of this ruling was probably to benefit the cop" is unreasonable. The cop isn't a party of interest and doesn't gain or loss anything from the decision either way. The Grant county circuit court ruled for the defendant, and here the Supreme Court reverse. At the state supreme court level, the judges know this is about much more than one case.
    – DavePhD
    May 23, 2015 at 18:55
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    @DavePhD: I see what you're saying, but despite the Court's claim that "an officer's interactions with people are not automatically adversarial", the reality is that this was an adversarial interaction -- the cop thought the car was suspicious, and treated it as such despite the lack of probable cause -- so for all intents and purposes, the Court ruled that the cop "won" this interaction. (And the Court's statement that "this is a close case" means that it's not a precedent for similar-for-slightly-different cases in the future, so it's not "about much more than one case".)
    – ruakh
    May 23, 2015 at 20:35

Another gem from the decision (EDIT: as @DavePhD correctly points out, this quote is from the earlier decision on the motion to suppress, but the S.Ct. decision supports this view more or less fully in paragraph 43, added below):

There is no evidence that Deputy Small "commanded" Mr. Vogt to roll down his window by tapping on the window and motioning that he roll down his window.

[43] Vogt's assertion that he was seized because of Deputy Small's "command" to roll down the window also is unpersuasive. The circuit court found in its decision on the motion to suppress that "[t]here is no evidence that Deputy Small 'commanded' Mr. Vogt to roll down his window by tapping on the window and motioning that he roll down his window." At trial, the court found that Deputy Small's testimony "would indicate that he wasn't commanding [Vogt] to do anything, . . . that he was simply trying to make contact." Even though the circuit court noted that Deputy Small maybe "wasn't quite as subtle as he thought he was being," the court still determined that Deputy Small's conduct was not so intimidating as to constitute a seizure. Thus, Vogt's arguments that he was seized due to a "command" from Deputy Small are unavailing.


On the flip side, of course, if you just try to leave in response to such an action by an officer, this will likely be found to constitute resisting arrest. In such a case, I expect the court would have the epiphany that there is no other reasonable way for an officer to make a show of authority to a suspect in a car whose windows are closed. Indeed, this seems to have bothered the circuit court:

The officer also testified that he did not block the vehicle in, that the vehicle could have gotten around him. So there are a few factual distinctions as far as the testimony. It's not a very bright line, and I don't know how a driver knows the difference between a command and a suggestion, particularly when we're talking about a physical movement, the knocking on the window.

Of course, you wouldn't want to fail to obey a command, because that can qualify as resisting arrest. Wikipedia has this to state about the crime of resisting arrest:


The courts in the United States of America regard resisting arrest as a separate charge or crime in addition to other alleged crimes committed by the arrested person. It is possible to be charged, tried and convicted on this charge alone, without any underlying cause for the original decision to arrest.

Bottom line, it's a Catch-22 that ensures that there is not much you can do when your car reeks of booze and a cop taps on the window and motions that you roll down your window. If you roll down the window, the officer just suggested that you do so and you're set for a DUI. If you try to drive off, it will turn out that the officer commanded that you roll down the window, and you're set for resisting arrest (which the cop can now legitimately arrest you for), plus DUI.

The idea that the officer would've simply let the defendant go about his business if he had simply driven off can be seen as an example of legal fiction.

  • You should make more clear what you are quoting, as the first quotation is really from the first circuit court decision on the motion to suppress. After that the circuit court reversed itself in a later decision. Then the county appealed to the state supreme court, which is the decision being discussed in the question.
    – DavePhD
    May 30, 2015 at 16:56
  • agree with the spirit of your answer, in the sense that there is some risk that the officer could be untruthful and say you resisted the officer if you drive away. But the resisting "arrest" aspect does not correspond to Wisconsin law, which requires that the violator "remains or becomes armed with a dangerous weapon or threatens to use a dangerous weapon" in combination with two other elements of the crime (section 946.415). At most it would be the lesser charge of resisting an officer (946.41). docs.legis.wisconsin.gov/statutes/statutes/946/IV/41
    – DavePhD
    Jun 1, 2015 at 14:13
  • "If you roll down the window... if you try to drive off" - What if you unlock your door and then let the cop make the next move (whether that's to open your door, verbally command you to roll down your window, or threaten you with his gun)?
    – Random832
    Jun 4, 2015 at 18:39
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    @DavePhD A car doesn't count as a dangerous weapon, and starting it in motion while the cop is standing next to it doesn't count as threatening to use it? I wouldn't bet on it.
    – Random832
    Jun 4, 2015 at 18:41


  1. The claim that

    you [can] legally drive away when Wisconsin police officer knocks on your car window

    does not logically follow from the actual finding unless you add a bunch of extra conditions. The actual finding was:

    that a law enforcement officer's knock on a car window does not by itself constitute a show of authority sufficient to give rise to the belief in a reasonable person that the person is not free to leave

    So, the court found that in a hypothetical situation in which a police officer knocks on your window and has shown no other sign of wanting you to pull over or stop, it would be a reasonable reaction to assume you are not being detained. And if you put it that way, it sounds more logical.

  2. Logically, in practice, you'll find that if the cop really did want you to pull over, but you drove away, they would then very quickly make it known that they want you to pull over, and you would have to pull over. Thus, this finding for all practical purposes means nothing. You'd get to go for a 2-second little drive, then you'd get the cop pulling you over.

  3. In this particular situation, the driver did not drive off anyway, so whether or not the court found this was never going to affect the driver in question.

    It merely came up as a hypothetical argument from the police themselves to defend themselves against accusations that they acted improperly. Basically, the cops said in court something along the lines of "but we weren't commanding him! we only knocked on his window! he could have left." In reality, he didn't leave, so this was more about determining whether the cops acted appropriately or not.

  4. Not that it matters, but in this situation, the driver was charged with offences during that incident, so it would also be incorrect if you claimed that someone escaped charges.

My source for the quote and other information I based parts 1, 3 and 4 on was wholly the same short opinion summary quoted in the article:


Part 2 of my answer doesn't have a source but was a logical argument I was making in response to the hypothetical situation presented by the article's headline.


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