Dougherty Ferry west of I-270 always patrolled by Des Peres Police, especially between interstate and Barret Station Rd. St Louis County patrols between Barret Station and Big Bend Rd. Usually cars are marked and on shoulder in either direction although they sometimes use side streets of nearby subdivisions. Also, traffic lights in area short cycle so police may be near lights monitoring intersections. Speed limits may not always be strictly enforced but red light enforcement is strict.