In a conventional storm overflow chamber of a combined sewer system, inflowing floating debris do not flow into an intercepting pipe in a rainy weather, and flow out to a public water body, causing a water pollution in the public water body. When a sub-switch receives a multicast data frame, it forwards the packet to one of the surrogate sub-switches. Each traffic signal device locally controls the state of the traffic signals, while communication between the traffic signal devices is used to synchronize the internal timers or clocks of the plurality of traffic control devices. Additionally, a variable orifice that adjusts resistance to extension and retraction of the rod is fluidly coupled between the hydraulic cylinder and the control valve. The molding material comprises highly porous open-cell plastic andor carbon aerogels, obtainable by the sol-gel polymerization of organic plastic materials, optionally followed by partial or complete pyrolysis of the plastic aerogel obtained.