On Interstate 12 nearing the St. Tammany/Tangipahoa Parish border crossing, there are trees in between the two spans of highway. When you reach the parish line, there is a small crossover that connects the two sides of the highway. State Troopers like to hide out in there, especially since it's not only hidden by the trees but there's also a little bit of curve to it, too.
They're not there all the time, but it's worth knowing. Sometimes I think they go there to take a break, because I see people go by much faster than me and they don't do anything.