When you’re pulled over on the side of the highway in a commercial truck, knowing the correct warning triangle distance is one of your first responsibilities.
You need to protect yourself, your truck, and other road users—and that’s where warning triangles come into play.
Or, as they’re also called, emergency triangles, reflective triangles, hazard triangles, or emergency reflective triangles. Knowing exactly how far apart to place them isn’t just good practice—it’s the law.
In this post, you’ll learn everything you need to know about warning triangle distance, including FMCSA requirements, best practices, and what kind of emergency reflective triangles are best for your fleet.
Vehicle maintenance violations can tank your CSA scores. Get a Free CSA Analysis and learn how to improve your vehicle maintenance program today!
👉 Click here to grab your Free CSA Analysis!
Why Warning Triangles Matter
Every time you stop on the shoulder, especially in low-visibility conditions or high-traffic areas, you’re at risk of being hit by passing vehicles.
Reflective triangles for trucks and LED road flares provide a clear, early warning to oncoming drivers that there’s a hazard ahead. Proper warning triangle placement helps prevent accidents, injuries, and fatalities.
And for commercial truckers, it’s not just a good idea—it’s mandated by the Federal Motor Carrier Safety Administration (FMCSA).
The FMCSA requires you to have the correct emergency equipment on your truck at all times and law enforcement will check for these during both Level 2 and Level 1 truck inspections.
DOT Emergency Equipment Video
Learn more about the DOT Emergency Equipment regulations and tips about how to apply them in this short video!
Warning Triangle Distance & Placement
According to 49 CFR §393.95 and 49 CFR §392.22, the FMCSA requires that every commercial motor vehicle (CMV), with some exceptions, carry three reflective triangles or equivalent emergency warning devices.
But it’s not just about carrying them—you have to know how to place them too.
When your truck is disabled on the roadside for any reason, you must place your emergency triangles:
- One triangle 10 feet from the front or rear of the vehicle, on the traffic side.
- One triangle approximately 100 feet behind the vehicle in the center of the lane.
- One triangle approximately 100 feet ahead of the vehicle in the center of the lane (on two-lane roads or undivided highways).
On divided highways (like most Interstate roads), you only need to place warning triangles behind the truck. (Your warning triangle distance would have to be at 10 feet, 100 feet and 200 feet back).
Important: If you’re stopped on a curve, hill, or anywhere your vehicle can’t be seen clearly from 500 feet away, place the triangles further out in the direction of oncoming traffic to give drivers more time to react.
Also, you must deploy the triangles within 10 minutes of stopping. Don’t wait!
How Many Reflective Triangles Should You Carry?
FMCSA regulations require you to carry at least three red reflective triangles in your truck at all times. These are standard equipment, just like your fire extinguisher or spare fuses.
Although not required, many drivers choose to carry extra triangles or supplement them with LED road flares for increased visibility. Just make sure the LED flares meet DOT or SAE safety standards.
** In May 2025, the FMCSA has proposed to remove the wording in the FMCSRs about “Liquid Burning Fuses “. **
Best Practices for Triangle Placement
Even if you know the official requirements, here are a few field-tested tips:
- Set your hazard flashers first. This gives you an extra layer of visibility before you get out.
- Be visible and safe. Wear your safety vest and watch for oncoming traffic when placing triangles.
- Walk toward traffic. Always place the furthest triangle first so you’re not walking between your truck and oncoming traffic.
- Avoid slopes or ditches. Place triangles on flat, stable ground whenever possible to prevent them from falling over.
Choosing the Right Emergency Triangles
Not all hazard triangles are created equal. Make sure yours are:
- DOT approved
- Weather-resistant
- Weighted for wind stability
- Bright red with reflective borders
Reflective triangles for trucks must be visible at night and in poor weather conditions. Consider carrying both standard triangles and LED road flares for maximum visibility.
FAQs: Warning Triangle Distance and Emergency Equipment
Q: What is the placement distance for warning triangles? A: Place one triangle 10 feet from the vehicle on the traffic side, one triangle 100 feet behind, and one triangle 100 feet in front (if on a two-lane undivided highway). On a divided highway, only place the rear-facing triangles at 10 feet, 100 feet and 200 feet behind the stopped CMV.
Q: How many red reflective triangles should I carry? A: You are required to carry three emergency reflective triangles in your truck at all times.
Q: When should I place the triangles after stopping? A: FMCSA rules require you to place them within 10 minutes of stopping.
Q: Can I use LED road flares instead of triangles? A: LED road flares can be used in addition to, but not in place of, the required red reflective triangles.
Q: What if I break down on a curve or hill? A: Adjust the triangle placement so drivers can see them from at least 500 feet away. That may mean placing the furthest triangle well beyond 100 feet.
Q: Are road triangles different from reflective triangles? A: The terms are often used interchangeably. Just make sure they meet DOT specifications for commercial vehicle use.
Final Thoughts
You never know when you’ll need to pull over, but when you do, having the right equipment and knowing exactly how to use it could save lives. Understanding the correct warning triangle distance is a small detail that makes a big difference.
Make it a habit to check your emergency triangle kit regularly, but at least during your Annual DOT Inspection. If one is damaged or missing, replace it before hitting the road. Not doing so could cost you valuable CSA points. And don’t forget your safety vest—staying visible is just as important as making your truck visible.
For more DOT compliance tips and tools, visit MySafetyManager.com. We help you stay safe, legal, and road-ready.
Stay safe out there!
You must be logged in to post a comment.