"selective enforcement" is an interesting concept...
I have a neighbor (lives across the lake from me) who is a retired police officer...23 years on the job...
I asked him once if there was any truth to the rumor that traffic cops had to meet a quota...
He said, "Not in so many words...every now and then the Captain, during the shift briefing would say, "Boys, I need to see some paper" and we all knew what he meant."