I believe you're correct. I remember this story about a Georgia cop who was known as the Drug Whisperer. He won all types of awards for the number of MJ DUI's he got. Once some local reporters started digging, they found numerous people, that were stone-cold sober driving home after finishing the second shift at work, who were arrested bc of his "training and suspicion". It was all subjective, and I believe a lot of his cases were eventually thrown out.
Drunk driving arrests are down sharply after decades of aggressive enforcement while drugged driving arrests are climbing. That's why Georgia has more than 250 officers with special 'Drug Recognition Expert' training. But the 11Alive Investigators...
www.11alive.com