Gravel Trucks

Does anyone know whether there is any enforcement of trucks actually using their covers? Almost every day I see trucks carrying full loads without covers, particularly on the stretch of I-55 South between the old bridge and I-240. That section of roadway also tends to accumulate a significant amount of loose gravel, and when trucks hit the bridge thresholds it’s common for debris to be thrown back toward other vehicles, which makes windshield damage almost inevitable.