That is a question open to debate. I have read court opinions that said 15 mins is far to long. Other times that is fine. The question is did they delay in finding the answer to the reason the stop was initiated. They cannot unreasonable extend the duration of the stop to wait for the K9 uniti.
Watch the video on YouTube "Breakfast in collinsville" then watch "lodging in collinsville"
I am trying to fight these K9 cases. The handlers can say anything is a positive alert Nd it is hard to challenge.
You or your attorney might want to present a claim of unlawful and excessive detention. One leading case on the subject is Knowles v Iowa, 525 US 113 (1998). If it wins, the evidence found might be suppressed. However, look out for police claims that they had reasonable fear for their safety, citing to Arizona v Gant, 556 US 332 (2009). If the cops had you get out of the car that improves your legal position. The longer the delay, the better your legal position. You can read these cases at googlescholar.com or findlaw.com.
Contact me at 248-399-6930 for a free consultation. You and I do not have an attorney-client relationship formed by our communications on this website. Advice given by me on this website is general advice based on partial information. You should not rely on any advice given without first hiring a lawyer in the area where the case is pending, and providing that lawyer with full information.
I will start by acknowledging that if I ever researched this specific question it was a long time ago and I do not remember exactly what I found. But my intuition is that the courts will hold that the controlling question is whether the detention and search were "reasonable" under all the circumstances, and this calls for a judgment call by the trial court judge based on the facts as developed at hearing on a motion to suppress. I imagine that you will not find specific codified time limit but rather numerous decisions holding that, on the facts of a particular case, a dog search and the resulting delay was or was not "reasonable."