When must you use your headlights?

The requirement to use headlights from sunset to sunrise and when visibility is less than 500 feet is grounded in the necessity to ensure safety on the roads. During nighttime hours, natural light diminishes significantly, making it essential for drivers to use headlights not only to see the roadway and surroundings but also to be seen by other road users. Additionally, when visibility is compromised, such as in fog, rain, or snow, using headlights helps illuminate the area and enhances awareness of hazards. This practice significantly reduces the likelihood of accidents.

Using headlights in bad weather or during specific conditions, as mentioned in other options, does not encompass the full range of situations where headlights are necessary. For instance, there may be instances when the sun is not yet set, but poor visibility still demands the use of headlights. Therefore, the requirement in option B provides a comprehensive guideline for when headlights should be utilized for safe driving.