Warning triangles can save a life — yours or another person’s — but only if you place them correctly.

In the heat of the moment after a crash or after your truck suddenly becomes disabled, things are happening fast and it’s easy to forget the proper procedure. As one CDLLife reader recently remarked, “I just passed a disabled truck and although he had his triangles out, they were all within 40′ of his truck. I see this type of setup all the time.

That’s why we thought it might be helpful to offer this quick refresher!

FMCSA Guidelines For Placing Warning Devices

  1. If you have to stop on the shoulder or on a lane of travel, turn on your hazards. From the Code of Federal Regulations 392.22
    “Whenever a commercial motor vehicle is stopped upon the traveled portion of a highway or the shoulder of a highway for any cause other than necessary traffic stops, the driver of the stopped commercial motor vehicle shall immediately activate the vehicular hazard warning signal flashers and continue the flashing until the driver places the warning devices (triangles).”
  2. Place the triangles within 10 minutes or as quickly as possible.
  3. When you’re carrying the triangles to place them, make sure that the reflective side is facing oncoming traffic so that you’re easier to spot. 
  4. If you’re in a lane of travel or on a shoulder of the highway, this is the requirement:“One on the traffic side of and 4 paces (approximately 3 meters or 10 feet) from the stopped commercial motor vehicle in the direction of approaching traffic;

    One at 40 paces (approximately 30 meters or 100 feet) from the stopped commercial motor vehicle in the center of the traffic lane or shoulder occupied by the commercial motor vehicle and in the direction of approaching traffic; and

    One at 40 paces (approximately 30 meters or 100 feet) from the stopped commercial motor vehicle in the center of the traffic lane or shoulder occupied by the commercial motor vehicle and in the direction away from approaching traffic.” The California DMV puts it this way: “If you stop on a 2-lane road carrying traffic in both directions or on an undivided highway, place warning devices within 10 feet of the front or rear corners to mark the location of the vehicle and 100 feet behind and ahead of the vehicle, on the shoulder or in the lane you stopped in.

    Warning Triangle Placement

  5. If you’re stopped on a hill, curve, or near a visual obstruction: “if a commercial motor vehicle is stopped within 500 feet of a curve, crest of a hill, or other obstruction to view, the driver shall place the warning signal in the direction of the obstruction to view a distance of 100 feet to 500 feet from the stopped commercial motor vehicle so as to afford ample warning to other users of the highway.”Warning Triangle Placement
  6. If you’re stopped on a divided or one-way road: “If a commercial motor vehicle is stopped upon the traveled portion or the shoulder of a divided or one-way highway, the driver shall place the warning devices, one warning device at a distance of 200 feet and one warning device at a distance of 100 feet in a direction toward approaching traffic in the center of the lane or shoulder occupied by the commercial motor vehicle. He/she shall place one warning device at the traffic side of the commercial motor vehicle within 10 feet of the rear of the commercial motor vehicle.” Warning Triangle Placement
  7. If you become stopped in a business district or residential area: “The placement of warning devices is not required within the business or residential district of a municipality, except during the time lighted lamps are required and when street or highway lighting is insufficient to make a commercial motor vehicle clearly discernable at a distance of 500 feet to persons on the highway.”

You can read the full text of the regulations on the placement of warning devices by clicking here.

Ashley Neely has been a lead content creator and social media manager with CDLLife since 2015. Her passion? Helping the men and women in the trucking industry get the news they need and the respect that they deserve.