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My Vehicle Broke Down – Now What Do I Do?

In this article, I respond to a question I’ve been asked regarding what am I legally obliged to do when stopping a commercial motor vehicle (CMV) on the side of the roadway due to a vehicle breakdown.

Let me begin by saying that stopping your CMV due to a breakdown or just to wanting to take a short break presents very serious hazards to both yourself and other motorists that you share the road with.

Because the general public doesn’t anticipate a CMV being stopped on the side of the road, collisions unfortunately do frequently occur.

Fatigued or distracted drivers are particularly at a high risk since they may not realize that a CMV is stopped at roadside, and they may try to move into what they think is an adjacent lane.

If the parked CMV encroaches in the live driving lane, other motorists may either misjudge the width of their lane, or not have time to move into another lane.

Since these types of collisions frequently occur at high speeds, the end result is frequently serious damage, injury and even fatalities.

Motor carriers should, therefore, train their drivers to avoid as much as possible stopping on the roadside, and only in emergency situations.

If such an emergency takes place requiring you to stop on the side of the roadway, you must know what your legal responsibilities are to do so safely, and to alert other motorists of your presence.

According to Part 392.22(a), the Federal Motor Carrier Safety Regulations (FMCSR) require you to immediately activate your vehicle’s 4-way hazard warning signal flashers any time an emergency requires you to stop on the traveled portion of a highway, or the adjacent shoulder of the highway.

The 4-way flashers must be left on the CMV until the emergency warning devices are placed according to regulations specified in Part 392.22(b).

Emergency warning devices must be placed within 10 minutes of stopping a CMV. The reality is that warning devices should be placed as soon as your vehicle is safely secured with your parking brakes set, especially at night or near well-lit backgrounds which can obscure a parked truck.

In order to protect your personal safety, when exiting the CMV to place the devices, you should carry them facing oncoming traffic for approaching motorists to see you.

Reflective triangles, lighted lamps and lighted fuses are examples of what is considered acceptable warning devices.

If stopped at roadside in an emergency, you are required to place 3 warning devices in the following manner:

  1. On the traffic side of the vehicle, 10 feet or four paces away, in the direction of approaching traffic.
  2. In the center of the traffic lane or shoulder occupied by the CMV, 100 feet or 40 paces behind, in the direction of approaching traffic.
  3. In the center of the traffic lane or shoulder occupied by the CMV, 100 feet or 40 paces in front, in the direction of oncoming traffic.
    Emergency roadside stop.
  4. If a hill, curve or any other obstruction prevents drivers from seeing the vehicle, a warning device should be placed at a distance of 100 to 500 feet to give plenty of notice to approaching motorists.

Emergency roadside stop2

  1. If the CMV is stopped on a one-way or divided highway, the warning devices should be placed at 10 feet, 100 feet and 200 feet, facing approaching traffic.

Emergency roadside stop3

Failing to use hazard warning flashers §392.22(a) carries 1 CSA Violation Severity point for Unsafe Driving.


This citation is often included with a driver for failing to or improperly placing warning devices §392.22(b), which will result in up 2 more CSA Violation Severity points.


Drivers are periodically getting cited by safety officials for incorrectly positioning disabled CMV’s on the side of the road, or in a breakdown lane without using their hazard warning flashers or properly placing their warning devices.

To prevent this from happening, motor carriers and drivers need to ensure that every CMV they operate has at least 3 warning devices such as safety triangles secured in the cab or on the vehicle.

Equally important is that drivers need to know how to properly deploy these emergency devices when they stop a CMV at roadside!

Have a safe day, and keep those wheels turning!