You must turn on your vehicle headlights if you cannot clearly see a person or vehicle how many metres away?

不能清楚看见多少米外的人或车辆时，必须开启汽车头灯？

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Also use a speed allowing safe stopping within the applicable visible distance. Dip in fog; reflected high beam can worsen visibility.

应同时降低到可在视线内安全停住的速度；雾中使用近光，远光反射可能令视线更差。