What are Hazard Lights?

Mary McMahon
Mary McMahon

Many automobiles use their front and rear signal lights to create hazard lights in a distinctive blinking pattern that can be used to alert other drivers to a problem. Typically, they run on the same circuit as regular lights, although they are controlled with a separate switch. Knowing how and when to use the hazards can be useful in an emergency situation, although drivers should also be equipped with highway flares.

The hazard lights are activated using a button near the steering console.
The hazard lights are activated using a button near the steering console.

Hazard lights are turned on with a small switch located near the steering column. Usually, it is in a separate area, so that the lights cannot be turned on accidentally by an unwitting hand. In many cars, the switch has a small triangular icon on it, and it is often red or orange, to make it more visible in emergencies. The two most common types of switches are tabs that need to be pulled and buttons that are pressed.

Hazard lights are used when a disabled car is parked on the side of the road.
Hazard lights are used when a disabled car is parked on the side of the road.

When the switch is activated, all of the turn signals on the vehicle will simultaneously illuminate and start flashing in a rhythmic pattern. This pattern is highly visible and very unique, so that drivers will not confuse it with turn signals or approaching headlights. As a general rule, drivers who see a vehicle with hazard lights on should slow down until they know what the problem is.

Most commonly, these lights are used on a disabled car that has been pulled to the side of the road. Especially at night, they increase the visibility of the car so that it will not be hit. It also alerts drivers to the fact that there is a problem of some kind, and some drivers use the lights to ask for help, usually in combination with leaving the hood up. Responders to an accident scene may also use their hazards to warn drivers about unusual conditions up ahead, and to help clear a lane for the accident.

Driving should never be done with the hazard lights alone, as this can be highly dangerous. These lights should also not be used to warn oncoming traffic about approaching hazards. A much better choice is for the driver to flash his headlights or lightly tap the horn. Using hazards may distract or confuse the oncoming driver, while flashing the lights is generally interpreted as a sign to slow down and be cautious. This feature can also be used to check whether or not all of the signal lights are working. When the car parked and safe position, such as in a driveway, the driver can turn the key to the “accessory” position and turn on the hazard lights on so that he can walk all the way around the car and make sure that no bulbs need to be replaced.

Mary McMahon
Mary McMahon

Ever since she began contributing to the site several years ago, Mary has embraced the exciting challenge of being a wiseGEEK researcher and writer. Mary has a liberal arts degree from Goddard College and spends her free time reading, cooking, and exploring the great outdoors.

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Discussion Comments


Hazard lights are for emergencies only! If the weather is too bad that you think you need them on, then you shouldn't be driving. It is especially idiotic if everybody turns them on while driving. It does not help. It only confuses everyone. Hazard lights are to warn others that there is a problem and the person should usually not be in motion.


The only time hazards should be used when you are driving is in a funeral procession, or if you are a volunteer emergency service going to an emergency or fire scene.


How about this? I was towing my brother's truck the other day with a strap. We had the hazards on to let people know. This is in Texas, by the way.

I slowed down and swung wide to turn into my driveway. As I went wide, the vehicle behind both of us tried to pass on the right side really quick. He clipped the front side of my truck on my passenger tire and fender and a little on the back side of my bumper. This was a two lane road with traffic going two ways as well. There was no shoulder or median.

I was told by the police officer (who was a friend of the person) I was at fault for not staying completely in my lane. I, on the other hand, let him know the passing lane is on the left and who in their right mind passes by someone with their hazards on who was slowing down at the time? What if I had to get out and the lights were a warning for someone to not pass and they would have hit me? Currently I'm fighting to make their insurance pay for it. What does everyone think of that?


Can they be used while following a friend's car to a place you have never been?


I was traveling through a snowstorm the other night, and every fool had their hazard lights on, even when in the left lane. Damn idiots. It was very distracting.


If you think that driving conditions are bad enough to warrant using hazard indicators, it's probably a good idea to pull over.


Some tail lights are not that visible when there is a severe rain storm that creates a fog, especially splash back from semis.

The use of the hazard lights alerts other vehicles to a potentially dangerous situation as most vehicles slow their speed during a torrential rainstorm. Rather than it being illegal, it should be legal or the transportation safety board should come up with something more visible and safer.


This lady at my daughter's school thinks just because her hazards are on she is allowed to stop in the middle of the road and hold up traffic. Wow.


Using hazard lights while driving in severe weather is extremely stupid, pointless and even dangerous. Why? Well, as others have stated, it can fool other drivers into thinking you're stopped when really you're in motion.

Now imagine if everyone had their hazard lights on while driving. Wouldn't that be distracting? How would you be able to tell if someone's in an emergency situation? His hazard lights? Not if everyone else is flashing!

Speaking of which, how would you be able to tell if a car's flashing its turn signal if the hazards are on?

Now a question: why is the turn signal stalk placed where it is? Because it's easy to access while driving. Same for the horn, cruise control switch, etc. Why is the hazard light button placed further away from the steering column? Because it's not meant to be used while driving!

Thanks for reading and be smart on the road. Don't use your hazard lights while driving. If you want to be sensationalist about the weather do it in your own living room; don't endanger others.


If anyone gets put into a ditch it is because of their own poor driving abilities. As an intelligent and reasonable person/driver, i think it is safe to use your flashers in severe weather because you are most likely going at a slow speed and there is the potential of your car losing control and becoming a hazard.


Hazard lights are for when you're on a local road only two lanes wise and you have to stop in the road because there's the rear end of a red jeep sticking out in the lane.


If visibility is low, such as in rain or snow, please use your *regular* lights, which have lights in both the front and the back and stay on constantly, rather than the hazard lights. Hazard lights are to indicate that you are a hazard, because you are traveling much slower than other traffic or are stopped in an improper parking space, not that there are hazardous conditions.


It is a very bad idea to drive in snowy conditions with your hazard lights on.

If you are using your hazard lights, it is expected that you are stopped and pulled over on the side of the road. You are not telling other drivers anything they do not already know by using hazard lights in snowy conditions.

If a driver catches up to someone with their hazard lights on while driving and slow speeds, they could interpret this as the vehicle is stopped, and attempt to go around, but if the vehicle is not stopped and the following driver attempts to pass, this could put them into the ditch.


While driving on Saturday just several days ago from Delaware to Maryland, I got caught in a blinding rain storm for two hours. Visibility was bad. Some drivers had hazard lights on and some did not. Would this have been a good or bad situation to use your hazard lights? I noticed the comment from anon38980


I hate it when people use their hazard lights in Florida in the rain, then they drive fast in the left lane on the expressway. Maybe more people will read this and figure out what the hazard lights are really for!

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