It's kind of hard to believe the same remains true in heavy rain, in the dark. I find that even the absence (or poor maintenance of) cat's eyes can be problematic then.
People would then be driving very very slowly which would have the same effect. You wouldn't believe it, but my friend drove 90 mph in fog so thick you couldn't see 10 feet out. This is because he had road markers and assumed the other drivers had their lights on so he would see them. If there were no road markers he'd be driving 30 mph.
