When a car is driving, it receives air resistance that acts opposite to the car's direction. The value of this air resistance is called the air resistance coefficient, and it is characterized by the fact that the value increases in proportion to the square of the speed. The higher the air resistance coefficient, the greater the air resistance that impedes the vehicle's movement, resulting in lower fuel efficiency. Therefore, for electric vehicles whose efficiency is important, lowering the air resistance coefficient is one of the important tasks. To solve such issues, cars utilize aerodynamic designs or add features such as active aero flaps that open and close according to the airflow. For example, Hyundai Motor Company's IONIQ 5 houses elements that lower the coefficient of air resistance, such as digital side mirrors, flush door handles, and aero wheels.