What is the required action if your commercial motor vehicle is at least 80 inches wide?

When a commercial motor vehicle is at least 80 inches wide, the required action is to activate hazard warning lights. This is important because activating the hazard lights increases the visibility of the vehicle to other road users, alerting them that the vehicle is wider than standard. This precaution is particularly necessary when the vehicle is stationary or if it poses a potential obstacle on the road, enhancing safety by reducing the risk of collisions.

The other actions listed may be relevant in different circumstances but do not specifically address the requirement for wider vehicles. For instance, turning on the headlights is a general safety measure rather than a specific response related to width. Engaging the parking brake is important for safety when parked but does not communicate the vehicle’s width. Exiting the vehicle immediately could pose safety risks rather than addressing the situation of having a wider vehicle on the road. Therefore, activating hazard warning lights is the most appropriate and effective action in this context.