If you are stopped for a traffic violation and an officer suspects there may be drugs in your car, you may end up having a drug dog sniff the interior and exterior of your car. But if the officer who stops you has to call for the dog, how long do you have to wait? The United States Supreme Court has said that a traffic stop can become unlawful if it is prolonged beyond the time reasonably required to complete the mission of issuing a ticket. So an officer is not allowed to stall the ticket writing just to wait for a drug dog. But if an officer has a reasonable suspicion that a particular person actually is, has been, or soon will be engaged in criminal activity, then the traffic stop may be extended. "Reasonable suspicion" requires specific, articulable facts, plus rational inferences from those facts, and the conclusion must be one that any reasonable officer would make. What kind of facts have officers used to show reasonable suspicion? Things like travel in a known drug area, extreme nervousness, prior drug charges, furtive gestures inside the vehicle, more than a hunch or suspicion. This is a situation where a lawyer will have to evaluate whether your constitutional rights have been violated.