The hwy patrol pull this one every so often on I55 in the middle of nowhere between St Louis and Cape Girardeau.
There is no "Drug Search" on the main hwy but at the bottom of an exit right after the sign there is.
The drug mules panic and get off the road to go around the supposed search and right into the arms of the hwy patrol.
It's surprisingly effective.
The locals who happen to actually use that exit are known by the hwy patrolman who lives there are just waved thru.
Similar to a DWI checkpoint - I encountered a drug specific roadblock driving through a small town in western New York state. This was a dozen years ago or so - the dissolution of liberty vis-a-vis the 4th ammendment has been going on for decades.
The roadblocks are not random though. Since they stop everyone and give everyone the same hairy eyeball, it's ok right? Equality under the of the law? That's the thinking of politicians and law enforcement.
We drove through NM (from TX) on our way to AZ for Thanksgiving and went through an immigration/drug checkpoint at 1:00 AM. They had the dogs out circling most cars but after they shined their flashlights in on us and saw two kids zonked in back, they sent us on through and didn’t walk the dogs around us. It was rather maddening having flashlights shined in our eyes while they asked a few questions and we couldn’t see their faces. I certainly didn’t offer up the fact that I had guns & ammo on board.
In my area the Border Patrol sets up a road block, stops all vehicles and runs the drug dog around some/all depending on the stop. It has been to court many times, just as DUI checkpoints have. I think it has something to do with stopping everyone as opposed to random stops. BUT, BP within 50 miles of the border also does a lot of random stops with/without dogs and asks to search sometimes. Supposedly the government, especially BP has extraordinary powers within 50 miles of border.