When should headlights be used?

Headlights should be used in specific situations to ensure safety while driving. The correct answer emphasizes that headlights are necessary not just during the hours of darkness, but also in conditions with limited visibility. This includes using headlights 30 minutes after sunset and 30 minutes before sunrise, when the daylight is fading or hasn't yet emerged, making it harder to see other vehicles and potential hazards.

The inclusion of the additional condition of using headlights anytime visibility is less than 500 feet is crucial. This situation can arise during adverse weather conditions such as rain, fog, or snow, where the clarity of the road and surrounding environment is compromised. Using headlights in these conditions enhances the driver's visibility and also makes the vehicle more visible to others, reducing the risk of accidents.

The other options are too limited in scope. For instance, using headlights only at night ignores essential conditions where visibility might be low during the day, while stating they are only for nighttime use disregards the critical aspect of driving safety at any time when visibility is poor. Thus, the correct usage guidelines reflect a more comprehensive approach to safe driving practices.