Final answer:
Headlights must be turned on one hour after sunset and one hour before sunrise as part of traffic safety laws to ensure vehicles are visible during periods of low natural light.
Step-by-step explanation:
The question "Headlights must be on one hour after sunset and one hour before sunrise" relates to traffic laws that are typically covered in social studies or a similar subject focusing on rules and civic education. This question appears to pertain to the knowledge required by drivers regarding when to use car headlights during different times of the day for safe driving practices.
The requirement to turn headlights on after sunset and before sunrise is based on the natural lighting conditions. As the sun sets, ambient light diminishes, necessitating the use of headlights for visibility. Similarly, before sunrise, headlights are necessary because the sun has not yet illuminated the roads sufficiently for safe driving. These regulations are typically mandated to increase safety by ensuring that vehicles are visible to each other during times when natural light is insufficient.