Picture this: it’s absolutely pouring rain as you’re driving along. You can barely see ahead of you, even with your headlights on. So you think to yourself “maybe I should flip on my hazards,” that way others can see you, or understand you’re driving slow. But depending on what state you live in, using your hazard lights in the rain may be illegal.

Which states is it illegal to use your hazard lights in?

There are only a handful of states where using your hazard lights while in motion is permitted, regardless of the weather. If you live in Alaska, Hawaii, Illinois, Kansas, Louisiana, Massachusetts, Nevada, New Mexico, or Rhode Island, it’s illegal to use them while driving, no exceptions. Florida was recently removed from that list, allowing drivers to use their hazards in the rain.

That said, there are also states where it’s perfectly legal to use your hazards, rain or shine. Those states include the District of Columbia, Georgia, Kentucky, Michigan, Mississippi, Missouri, Nebraska, New Hampshire, New Jersey, Pennsylvania, South Dakota, Texas, Utah, Vermont, and Wyoming.

Every other state falls into some grey area where it’s illegal in some situations, and legal in others. For a full list, visit AJC.com, but to understand why they’re illegal in the rain, you have to know what hazard lights are used for.

Why is it illegal to use your hazards in the rain?

First of all, hazard lights alert emergency vehicles that there’s a stopped car on the side of the road. That’s their primary function, which means that hazard lights should really only be used when stopped. However, it’s become a common practice for drivers to flip them on if they intend on going slower than the flow of traffic. In some ways, this is a good thing, and in others, it’s quite dangerous.

On most cars, the usage of hazard lights takes away the use of the turn signals. So if you flip on your signal, the indicator might not flash (unless you manually turn off the hazard lights first). Drift out of your lane without everyone being aware and… you know the rest.

In the rain, or fog, or in environments with limited visibility, all those dangers are amplified. People may try to speed past if you use your hazards because they think going too slow. Or it might look like your stopped, even if you’re just going slower. It’s an added layer of confusion, and it’s best to only use them when it’s necessary.

When should you use you hazard lights?

Are you in the slow lane and pulling over to the side of the road? If so, use your hazard lights. Are you stopped at the side of the road? If so, use your hazard lights.

Really, you only want to use your hazard lights if you’re on the side of the road, or if you get into an accident. They let other drivers around you know that your car is a “hazard,” an obstacle in the way. If someone else needs to get to the shoulder, they’ll see you and your lights before pulling over themselves.

Ideally, however, you never want to be in a situation where you have to flip on your hazards. And we’d suggest not using your hazards in the rain regardless of what state you’re in. Just make sure your brake lights and blinkers work so there’s no confusion between you and the other drivers on the road.