What is the function of width indicator lights?

[OKaylee]

Width indicator lights are the outermost lights at the front and rear of a vehicle, indicating the vehicle's width. Their primary function is to signify the presence of the vehicle and its approximate width during nighttime driving, aiding other vehicles in judging during encounters or overtaking. There are three situations when width indicator lights should be turned on: 1. Mandatory during nighttime driving (traffic regulations require both width indicator lights and rear position lights to be on at night); 2. Essential during rainy or foggy weather when visibility is poor, serving as a warning reference for preceding, following, and oncoming vehicles; 3. Useful during dusk driving to enhance visibility for other drivers.