What is the plastic under the car door?

[Ella]

The plastic under the car door is the side skirt. Below are the functions of the car side skirt and methods to prevent it from rusting: Functions of the car side skirt: The side skirt refers to the skirt panel installed on both sides of the car body, which also acts as an air dam, reducing the airflow entering the underside of the car from the sides. It has a certain turbulence effect, significantly reducing air resistance. At high speeds, it enhances driving stability. When the car is running at high speeds, it prevents the vehicle from drifting. Methods to prevent the car side skirt from rusting: Try to park the car indoors; ensure the vehicle is parked in a dry environment; promptly clean sludge from gaps and the floor inside the car.