When must headlights be dimmed for oncoming traffic?

Headlights must be dimmed for oncoming traffic to reduce glare in an oncoming driver's rearview mirror. When a vehicle approaches with its high beams on, it can create significant glare, which may impair the vision of the oncoming driver. This is particularly important at night or in low-visibility conditions. Dimming headlights ensures that oncoming traffic can see safely and clearly, thus enhancing overall road safety and preventing potential accidents.

The practice of dimming headlights to low beam within a specified distance—typically within 500 feet of an oncoming vehicle—is a standard traffic regulation to promote safe driving practices. It demonstrates consideration for other drivers on the road and helps ensure that everyone can navigate safely.