Originally Posted by Da Jeeper
I just changed my overland hid to the D3S - Philips X-tremeVision bulb
Don't even need the fogs anymore, there that good...tried the fogs last night in a storm, couldnt even see them...with factory bulbs they helped, D3S are bright and fill in the space of the fogs
The fogs aren't supposed to be brighter than the headlights. In fact, they aren't even supposed to reach as far as headlights. Their purpose and design is to provide a lower, wider and more saturated light spread for...wait for it...foggy and misty conditions. This pattern lights up a pathway close to the ground but does not light the airborne particles in the line of sight - this increases the visibility in bad weather.
The color of light is important as well. A warmer or more yellow light isn't as reflective off the airborne particles and is able to penetrate further before the glare of reflection becomes an issue.
Think of driving through a snow storm. When you click on your brights, suddenly the area immediately in front of your vehicle is saturated with a white wall of light but you can't see very far. Switching back to low beams allows you to actually see further because the lights are directed more downwards instead of straight ahead which reduces the amount of light being reflected back at your face.