The City of St. Louis (a separate political entity from St. Louis County, separated by the River Des Peres at 44) has a creative history of scrounging revenue. Here, they have created their own Highway Patrol-like DOT unit. It’s usually eastbound, starting at the River Des Peres bridge (where there’s a light-rail commuter train overpass, mm285), and they drive unmarked very dark-colored pickup trucks or SUVs. Sometimes they’re westbound, and they’ve been known to creep around I-70 and other parts of The City.