Duìmiàn lái chē de shíhou, yào bǎ yuǎnguāngdēng huànchéng jìnguāngdēng.
When a car comes the other way, switch from high beam to low beam.
Tips
usage
近 "near" and 远 "far" name the two settings: 近光灯 lights the road just ahead, while 远光灯 reaches far but dazzles oncoming drivers. The headlights themselves are usually called 大灯.
