This story is pretty dang funny, especially considering how cheesy the sign looks, thought it does makes me wish I could do something equivalent in my neighborhood:
With the help of a local sign company, [Rick] Pyburn constructed a two-dimensional plywood Benton County sheriff’s car, well, the front half of one anyway.
After setting the decoy up in some bushes near the road, Pyburn saw a marked improvement.
“Once I placed that on the highway, it was amazing,” he said. “The traffic immediately slowed down.”
Pyburn realizes the plywood car is not all that realistic looking, and that commuters on the route may realize it’s a fake, but just a glimpse of the silhouette has a psychological impact on drivers, he said.
I remember driving through Southeast Oregon one time (on my way towards Tahoe) and running through a small town that kept a dummy police car on the edge of town to slow down speeders. I know I slammed on my brakes. The only reason I knew it wasn’t a real car was because the locals were laughing at me and told me the story about it. Apparently they move the car periodically to keep folks on their toes. I just wish I could remember where I saw that (will have to go dig up my Oregon atlas later).