What is the rule for using a car's emergency lights in the rain?

Question

I'm in Mid-South Carolina, and lately there have been several really heavy downpours to the point of you almost driving blind. I have noticed that many, but not all, motorists in these conditions turn on their flashing emergency lights. Is this a law, or are people needlessly warning you of the rain (it seems moot to have them on, we can see your lights anyways and we KNOW that its raining heavily)?

Answer 1

In a situation where you are "almost driving blind" another driver's use of the four way flashers may help you see that there is a car ahead of you. They are calling attention to their vehicle, and to the fact that they are going slower than normal. Any slow moving vehicle presents a hazard on the roadway.

"it seems moot to have them on, we can see your lights anyways " Flashing lights draw more attention than do non flashing ones. That is why emergency vehicles have flashing lights! The flashers also are brighter than the normal running lights.

Answer 2

Hiya. Im in the UK but i imagine the rule would be the same. You are only supposed to use your hazard/emergency lights in the following circumstances:-

- to warn other road users of a hazard ahead (that you may need to break sharply for)
- when you have broken down at the side of the road

So i would imagine they should be using their FOG LIGHTS as apposed to their hazard/emergency lights
You should use fog lights if visibility is less than 100m.

Hope that helped :)