When operating a CMV, what safety measure is always required?

Wearing a safety belt is always required when operating a commercial motor vehicle (CMV) because it is a critical safety measure that significantly reduces the risk of injury in the event of a collision. Safety belts are designed to keep the driver securely positioned in the seat, preventing ejection from the vehicle and minimizing movement during an accident. This requirement aligns with federal regulations and state laws, emphasizing the importance of driver safety and the protection of all vehicle occupants.

In contrast, while wearing a hard hat, gloves, or reflective clothing may be necessary in specific contexts, such as construction sites or high-visibility environments, they are not universally mandated for the operation of CMVs. Therefore, the safety belt stands out as the essential safety measure applicable to all drivers of commercial vehicles.