When are you required to have your headlights on during the day?

The requirement to have your headlights on when visibility is limited to 500 feet or less is based on the need to ensure safety in conditions that can impair a driver's ability to see and be seen. During situations such as fog, heavy rain, or snow, visibility can be substantially reduced. Using headlights in these conditions not only helps the driver to see the road and other vehicles more clearly, but it also makes the vehicle more visible to others, reducing the likelihood of collisions.

While headlights are also required at night and can be beneficial in rainy conditions, the specific requirement to use them when visibility is severely limited focuses on addressing conditions that pose a particular risk. The other options do not account for this specific criteria, as having headlights on at all times may not be practical or required by law, and having them only at night or when it’s raining does not cover all scenarios of decreased visibility.