Yesterday on my way in to work, I got an early warning from an LEO that was hidden on an on ramp thats high above the highway I was traveling on. Basically the onramp is a hill that declines onto the highway.... therefore the ramp and cars on it are out of view from the highway until you're parrallel with the bottom of the ramp.
I got a warning before the overpass, and it ended up that there was an LEO high on the ramp shooting down the ramp to get cars traveling away from him. Without a detector I NEVER in a million years would've seen the state trooper. I had to look for him in my rear view mirror up the ramp as I was hit full blast with Ka, and the V1 arrows switched to the rear. It was an amazing save.