Which of the following is a requirement for vehicle headlights?

The requirement that vehicle headlights must shine 500 feet away at maximum intensity is essential for safe driving conditions, particularly during nighttime and in low-visibility situations. This distance ensures that a driver can adequately see the road ahead and any potential hazards well in advance, allowing for timely reactions and decisions. Adequate headlight illumination is vital for not only the driver's visibility but also for making the vehicle visible to others, enhancing overall road safety.

In many jurisdictions, headlights are regulated not only for brightness but also for their alignment and effectiveness in lighting the roadway clearly without causing glare for oncoming traffic. Meeting the required distance helps ensure that headlights serve their purpose efficiently.

The other options reflect misunderstandings or misapplications of typical headlight regulations. For instance, yellow headlights are not a standard requirement; headlights must be white or slightly bluish to comply with most vehicle laws. The notion that headlights should be turned off during the day contradicts the practice of using daytime running lights to improve visibility. Dimmed headlights at night, while common practice in light traffic or with oncoming vehicles, must comply with regulations that prioritize safety and road illumination.