When should a driver dim his headlights for oncoming traffic at night?

Dimming headlights for oncoming traffic at night is a crucial practice that enhances safety on the road. The correct answer, which indicates that drivers should dim their headlights at 500 feet before encountering oncoming vehicles, is rooted in the principle of preventing blinding glare that can impair the vision of other drivers.

Headlights are bright and can create significant glare, which is particularly dangerous for oncoming traffic, as it may temporarily blind the driver or obscure their view of the road. Dimming headlights at a distance of 500 feet provides adequate time to adjust the brightness before crossing paths with another vehicle, ensuring both drivers maintain visibility and safety.

The recommended distance is designed not just for the safety of the oncoming vehicle, but also to allow the driver time to react appropriately and continue driving safely. In contrast, shorter distances might not provide sufficient time for drivers to adjust their headlights and would increase the risk of accidents.