Warning Triangles: Rules, Placement, and Tips
Warning Triangle Guide
A truck stopped on the side of the road is a hazard, especially at night or around a curve. Other drivers need a clear sign, far enough back, to slow down and move over.
That is the job of warning triangles. They are simple, fold flat, and can save lives. This guide explains the rules for commercial trucks, where to place them, and how to pick a good set.
In This Guide
What Are Warning Triangles?
They are red, reflective triangles that stand up on the road. The red border shines brightly when headlights hit it. Most have a weighted base so they stay up in wind.
They fold flat and store in a small case. Most drivers keep them in the cab or a side box.
Who Needs Them?
In the United States, federal rules require commercial motor vehicles to carry three bidirectional reflective warning triangles. Bidirectional means they reflect light from both the front and the back.
Even if you drive a pickup or a car, a set of triangles is a smart part of any roadside kit.
When to Put Them Out
If your truck is stopped on the traveled part of the road or the shoulder, you need to set out your warning devices. The federal rule says to do it as soon as possible, and within 10 minutes of stopping.
Turn on your hazard flashers right away. Leave them on while you set out the triangles.
Where to Place Them
Placement depends on the type of road. Here are the basics from the federal rules. Always check the current rules for exact details.
| Triangle | Two-Lane Road or Undivided Highway | One-Way Road or Divided Highway |
|---|---|---|
| 1 | On the traffic side of the truck, about 10 feet away (about 4 paces) in the direction of approaching traffic | About 10 feet behind the truck |
| 2 | About 100 feet behind the truck (about 40 paces) | About 100 feet behind the truck |
| 3 | About 100 feet ahead of the truck | About 200 feet behind the truck (about 80 paces) |
On a one-way road or divided highway, all three face the traffic coming toward you.
Hills, Curves, and Other Blind Spots
If a hill, curve, or other blocked view hides your truck, place a triangle farther back, up to 500 feet away. This gives drivers more time to see the warning.
How to Set Them Out Safely
- Pull as far off the road as you can. Turn on your hazard lights.
- Put on a safety vest. You need to be seen while you walk.
- Carry the triangles facing traffic. Hold them in front of you so drivers see them as you walk.
- Walk on the shoulder, facing traffic when you can. Stay as far from the lane as possible.
- Set each one firmly. Make sure it stands up and will not blow over.
- Pick them up in reverse order. Start with the one farthest from the truck and walk back.
What to Look for in a Good Set
- Bright reflective border. It should shine from far away.
- Weighted base. It keeps the triangle standing in wind.
- Strong frame. It should not bend if it gets bumped.
- Folding design. It should store small.
- A case. A case keeps the triangles clean and together.
The Safe & Tie triangle warning frame folds for compact storage and has a reflective surface for high visibility.
Keep a Full Emergency Kit
Triangles work best as part of a full roadside kit. A good kit includes:
- ✔ Three warning triangles
- ✔ A high visibility safety vest
- ✔ Gloves
- ✔ A flashlight
- ✔ Jumper cables
- ✔ A fire extinguisher, mounted and charged
The Safe & Tie vehicle safety emergency kit includes triangles, a safety vest, jumper cables, and work gloves. You can see more in the safety equipment collection.
Care Tips
- Wipe the triangles clean so the reflectors stay bright.
- Check that the frames still snap together.
- Replace any triangle that is cracked or faded.
- Keep the case in the same spot so you can find it fast.
Common Mistakes
- Placing triangles too close to the truck
- Forgetting the triangle on a hill or curve
- Setting them out without a vest on
- Leaving them behind when you drive away
- Carrying only one or two
Final Thoughts
Warning triangles are one of the cheapest safety items on your truck, and one of the most important. Carry three, set them out within 10 minutes, and place them the right distance for the road you are on. Wear a vest, stay alert, and pick them up when you leave. They give other drivers the time they need to see you and steer clear.
Be Seen on the Shoulder
Shop warning triangles and roadside safety gear at Safe & Tie.
Shop Warning TrianglesFrequently Asked Questions
How many warning triangles does a truck need?
Commercial motor vehicles must carry three bidirectional reflective triangles.
How far back do I place them?
On a divided highway, about 10, 100, and 200 feet behind the truck. On a two-lane road, one near the truck and one about 100 feet in each direction.
Can I use flares instead?
Flares and other devices are allowed in some cases, but some vehicles, such as those carrying certain hazardous materials, cannot use flares. Triangles work for everyone.
Do pickup trucks need warning triangles?
Personal pickups are not usually required to carry them, but they are a smart safety item.
How fast do I need to set them out?
As soon as possible, and within 10 minutes of stopping.