Can a drug dog sniff my car during a traffic stop?

A dog sniff of the exterior of a vehicle, conducted during a lawful traffic stop, is generally not treated as a search requiring independent justification. So the sniff itself is usually not the issue.

The issue is time. A traffic stop may last only as long as reasonably necessary to complete its mission — checking the license, running the tag, writing the citation. Once that's done, or once the officer stops working on it in order to pursue something else, the clock becomes a problem.

That's the analysis in most K-9 cases. Not whether the dog sniffed, but whether the stop was still lawfully in progress when it did. Officers who slow down the paperwork, or who ask unrelated questions while waiting for a unit to arrive, create exactly this issue.

Timestamps settle it. Dispatch logs, body cam, and the citation's own time entries can establish when the mission was complete.