When should headlights be used in a commercial vehicle?

Headlights should be used during low visibility conditions, which is highlighted in the correct answer. This includes situations such as nighttime driving, fog, heavy rain, snow, or any other circumstance that significantly reduces visibility. Proper use of headlights in these scenarios enhances safety by making the vehicle more visible to other road users and improving the driver's visibility of the road and surroundings.

While it is true that headlights should be used during low visibility, it is important to note that headlights provide essential illumination even in daylight conditions, such as during gloomy weather. Therefore, while the option about using headlights at all times while driving may seem appealing for safety reasons, it serves to emphasize the necessity during reduced visibility conditions, which is the primary focus. Ultimately, using headlights is part of good driving practice and promotes safety in diverse driving conditions.