Actually, no. They cannot use your refusal to consent as grounds for a search.

Edit: Misread. I guess they could call out the drug dog and delay you in that way as an attempt to intimidate you into consenting. However, they will still need your consent or a warrant to search the vehicle, or the drug dog getting a positive. I would be interested in seeing what happens on a search from a false positive from the dog.

I, personally, would challenge their right to detain me for a traffic violation in order to wait for the dog to show up. Especially if it was something like a broken taillight or something hanging from my mirror.

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