But fog lights don't really prevent you from crashing. They do not output that much light and unlike your headlights and highbeams, they are not directed, but j

But fog lights don't really prevent you from crashing. They do not output that much light and unlike your headlights and highbeams, they are not directed, but just scatter light in front of you. In the UK, it's not legal to have the fog lights on unless your visibility is less than 100 metres in front of you. That's basically the same range as your dipped lights have, and less than five seconds worth of visbility if you're doing 80 km/h. If your visibility is reduced so much, your best bet against crashing isn't just to scatter some light near the bottom of your front bumper, but to engage the rear fog lights and drop your speed significantly.