https://www.techdirt.com/articles/20200505/10462744438/federal-court-says-every-drug-dog-utah-is-unreliable.shtml

For as long as people have been driving, cops have been imagining reasons to pull them over and coerce them into "voluntary" searches. The Supreme Court's Rodriguez decision (sort of) put an end to extended stops -- the ones that start with a perceived violation that's dragged out until a drug dog arrives. Unfortunately, that decision only removed part of the equation. The Supreme Court's Heien decision made it possible for cops to rely entirely on pretext to engage in fishing expeditions by saying cops only had to think they witnessed a traffic violation, rather than actually be accurate about the laws they're tasked with enforcing.

Cops are still trying to bring drug dogs to routine traffic stops. The Rodriguez decision is generally taken to mean cops just need to be quicker about rustling up a K-9 unit. Cops love drug dogs because they allow cops to perform the warrantless searches they want to perform. The drug dog's handler can call literally any movement by the dog an "alert," turning normal dog behavior into "probable cause" for a search. It doesn't help that the dogs are rewarded for every alert and given no positive reinforcement for failing to find anything interesting.