China manufacturer of magnetic ballasts for metal halide flood lights & hps flood lights

Of course, through fog and strong high pressure sodium lamp, high pressure sodium light emitted wavelength longer than metal halide lamp, through fog better than the metal halide. So Highway Lighting ordinary uses high-pressure sodium lamps. From the economic point of view: high pressure sodium lamp life than metal halide about double the price is cheaper. With hps ballasts the same power efficiency of high-pressure sodium lights to be higher than the metal halide. if not required light color,  Choosing the high-pressure sodium lamp is better.