When can you use full beam headlights?

When there are no approaching vehicles
Driving in fog
Driving when it's snowing
When a police officer is giving directions

The correct answer is "when there are no oncoming vehicles." The importance of this regulation lies in its consideration for nighttime drivers who need good lighting to ensure driving safety, while also preventing unnecessary interference and hazards for oncoming drivers. Using high beams when there are no oncoming vehicles maximizes visibility, helping drivers avoid potential obstacles and dangers. However, once an oncoming vehicle is detected, the driver should immediately switch to low beams for the safety of the other driver.