When should a driver use their high beams?

A driver should use their high beams when there is no oncoming traffic because high beams illuminate the road more effectively at greater distances, allowing the driver to see further ahead. This is especially useful in dark, open areas where there are few or no streetlights. However, using high beams is not appropriate when there are oncoming vehicles, as it can blind other drivers and create a dangerous situation.

In contrast, using high beams in fog can actually reduce visibility because the light can reflect off the water droplets, creating a glare. Therefore, low beams are recommended in foggy conditions. While it's common to use high beams on rural roads where traffic is sparse, the critical factor is the presence of other vehicles, rather than the type of road. Thus, the best practice is to switch to high beams only when the road is clear of oncoming cars.