Fog lights, in my understanding are not designed just to be brighter. They emit a wide and short angle(beam) of light close to the ground so as to illuminate the road rather than the mist of the fog. Low beam and high beam lights have a much longer and narrower beam of light. High beam headlights beam od light is much higher and longer, making them not a good choice in fog. I'd like to get a set of fog's installed.......i'm sure they would help with the low-beams in dense fog.