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When to Use Your Hazard Warning Lights — and When Not To

Stephen Fogel
February 28, 2019

All cars come with hazard warning lights as standard equipment. Also known as “hazards,” “emergency blinkers” or “four-way flashers,” these lights help your fellow drivers see you when something is wrong with your car, or when you need to stop unexpectedly.

When you turn on your hazard warning lights, all four of your turn signals flash at the same time. The system has its own separate dashboard control switch, usually identified with a red safety triangle symbol. If you can’t find the switch for your hazard warning lights, check your owner’s manual.

 

When should you use your hazards?

It depends. Each state has its own regulations regarding hazard warning lights. For more details on each state’s laws about hazard warning lights, you can check here.

While there’s a lot of variation between how each state regulates using the lights while the car is in motion, there’s a general consensus relating to using them when it’s stationary (and one specific driving scenario):

  • When your car breaks down or gets a flat tire: If your car is stuck by the side of the road, you should turn on your hazard warning lights to alert surrounding traffic that you have a problem.
  • If the police pull you over: In this situation, first activate your turn signal, find a safe place to pull over, out of the way of surrounding traffic, then turn on your hazard warning lights to notify passing motorists to drive past carefully. 
  • If you encounter an emergency in the roadway: You may come upon the aftermath of a recent auto accident, or perhaps a tree or other debris has fallen into the road. The flow of traffic may be blocked, bringing you and other cars to a standstill. In this situation, activate your hazard warning lights to slow down other drivers who are approaching the area.
  • If the weather makes you stop: If you get caught in a bad snowstorm, torrential rains or dense fog, it might not be safe to drive. First, pull off of the road as far as possible, so that the traffic behind you will not drive into the back of your vehicle. Turn on your hazard warning lights to indicate that you have pulled over and stopped your car.
  • If you are driving in a funeral procession: This is the single universally approved situation in which you can legally drive with your hazard warning lights on. The funeral director will usually provide additional guidance on this when you line up for the procession. 

When should you not use your hazards?

Again, each state has its own rules about when you can and can’t use your hazards. For easy reference, here are the states that don’t let you use the hazards while in motion (except for a funeral procession):

  • Alaska
  • Florida
  • Hawaii
  • Illinois
  • Kansas
  • Louisiana
  • Massachusetts
  • Nevada
  • New Mexico
  • Rhode Island
  • Tennessee
  • Wyoming 

A final word on your hazard warning lights

It’s important to switch off your hazard lights when the need for them has passed. Driving with them on is distracting, and may also be illegal in your state.

Keep your hazard warning lights in good condition. If you notice that one or more of your turn blinkers are not working, it likely means they won’t work when you put the hazards on. Replace them promptly or have a mechanic fix the problem.

Stephen Fogel

About the Author

Stephen has been an automotive enthusiast since childhood, owning some of his vehicles for as long as 40 years, and has raced open-wheel formula cars. He follows and writes about the global automotive industry, with an eye on the latest vehicle technologies.

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