This is stipulated in the Traffic Law Enforcement Regulations: when a motor vehicle is driving at night, there is no street lamp, and the lighting is poor, or in case of fog, rain, snow, sand dust, hail and other low visibility conditions, the headlights, position lights and rear position lights should be turned on, but the rear vehicle driving in the same direction should not use the high beam when it is driving close to the front vehicle. Motor vehicles should turn on fog lights and danger warning flashlights when driving in foggy days.
It's definitely wrong to honk the horn at high frequency. If you drive a long-distance bus, you can't keep honking like that. In some cities, honking is forbidden.