What does 49 CFR 392.22 (Emergency signals; stopped commercial motor vehicles) require?

Short answer

49 CFR 392.22 requires the driver of a stopped commercial motor vehicle to immediately activate the vehicular hazard warning signal flashers and place warning devices as specified. The warning devices must be placed within 10 minutes of stopping, and the driver must use three bidirectional reflective triangles or at least six fusees.

The rule says

"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 required by paragraph (b) of this section." (49 CFR 392.22(a))

1. "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"

2. "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"

3. "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." (49 CFR 392.22(b)(1))

In plain English

When a commercial motor vehicle stops on the side of the road, the driver must turn on the hazard lights right away and keep them on until warning devices are placed. The warning devices, such as reflective triangles or fusees, must be put out within 10 minutes of stopping. The placement of the warning devices is specific, with one device on the traffic side near the vehicle, one 100 feet ahead in the direction of traffic, and one 100 feet behind in the opposite direction.

What to do

• Immediately activate the hazard warning signal flashers when stopping a commercial motor vehicle.
• Place warning devices, such as three bidirectional reflective triangles or at least six fusees, within 10 minutes of stopping.
• Position the warning devices as specified in the regulation: one near the vehicle, one 100 feet ahead, and one 100 feet behind.
• Ensure the warning devices are visible and effective in alerting other drivers to the stopped vehicle.