In most of Europe, where traffic laws nearly always seem to make more sense, the *opposite* isn't allowed. You cannot use your fog lights with your head lights. If you've ever driven over there, you know that driving in the fog with only your fog lights and no head lights significantly improves visibility. The entire point of the fog lights is to have an alternative to the head lights, to use in the fog.

So why does the US say that we cannot take advantage of this, but have to use our head lights as well?

(Yes, this upsets me slightly. :))

...trying to figure that one out also, since turning on the headlights totally defetes any advantage given by the fogs. Hope someone comes up with an answer! :-)

Yep; me again!