DOT Triangle Requirements: Placement, Timing & What 49 CFR 392.22 Actually Requires
Published: August 9, 2026 · By Anne Johnson
TWO SEPARATE RULES, OFTEN CONFUSED
DOT triangle requirements actually come from two different sections: §393.95 requires that a truck carry three reflective triangles in the first place, and §392.22 governs exactly where and when they have to be placed once the vehicle is stopped. Most guides stop at "carry three triangles" — this one covers the placement rule in full, since that's the part drivers actually get tested and inspected on.
THE 10-MINUTE RULE
When a commercial motor vehicle is stopped on the traveled portion or shoulder of a highway, the driver must place the warning devices within 10 minutes of stopping. This isn't a suggestion — it's a specific timing requirement in §392.22, and it applies regardless of why the vehicle stopped, as long as it's a breakdown, disablement, or unplanned stop rather than a normal traffic stop.
STANDARD PLACEMENT: TWO-WAY ROAD
On a road with traffic moving in both directions, the three triangles go:
- One triangle on the traffic side of the vehicle, approximately 10 feet (4 paces) from the vehicle, in the direction of approaching traffic.
- One triangle approximately 100 feet (40 paces) from the vehicle, in the center of the traffic lane or shoulder occupied by the vehicle, in the direction of approaching traffic.
- One triangle approximately 100 feet (40 paces) from the vehicle in the opposite direction.
PLACEMENT ON A DIVIDED HIGHWAY OR ONE-WAY ROAD
Where there's no oncoming traffic from the opposite direction — a divided highway or one-way street — all three devices shift to warn traffic approaching from behind the vehicle instead:
- One triangle within 10 feet of the rear of the vehicle.
- One triangle approximately 100 feet behind the vehicle.
- One triangle approximately 200 feet behind the vehicle.
WHEN PLACEMENT ISN'T REQUIRED
§392.22 includes a business/residential district exemption: triangle placement isn't required within the business or residential district of a municipality, except during the period when lighted lamps are required and street or highway lighting is insufficient to make the vehicle clearly visible from 500 feet away. In practice, this means a stopped truck on a well-lit city street during daylight generally doesn't trigger the placement requirement — but a stop after dark on a poorly lit stretch does, district or no district.
WHAT THE TRIANGLES THEMSELVES HAVE TO MEET
Beyond placement, the triangles carried have to meet FMVSS 125 (49 CFR §571.125) reflectivity and construction standards. Not every reflective triangle sold online is FMVSS 125-compliant — check for the labeling before assuming a triangle satisfies §393.95.
THE COMMON MISTAKE
The most frequent placement error isn't forgetting the triangles — it's misjudging the 100-foot and 200-foot distances, especially at night or on unfamiliar roads. Pacing it off (roughly one long stride per 2.5 feet) is more reliable than guessing, and it's worth training new drivers on the actual step count rather than assuming they'll estimate it correctly under pressure.
For the full equipment requirement behind this rule, see our DOT truck safety equipment requirements checklist. Browse FMVSS 125 reflective triangles.
FAQ
HOW LONG DO I HAVE TO PLACE WARNING TRIANGLES AFTER STOPPING?
10 minutes from the time the vehicle stops on the traveled portion or shoulder of the highway.
WHERE DO TRIANGLES GO ON A ONE-WAY ROAD?
All three shift behind the vehicle: one within 10 feet of the rear, one at approximately 100 feet, and one at approximately 200 feet.
DO I NEED TO PLACE TRIANGLES IF I'M STOPPED IN A CITY?
Not within a business or residential district, unless it's during hours requiring lighted lamps and the street lighting isn't sufficient to make the vehicle visible from 500 feet.
