The wheels of cars or automobiles are made circular for the purpose of reducing the frictional force. The rolling friction is lesser than sliding friction, therefore, wheels are made circular in shape. Had the wheels been of any other kind of shape, then sliding friction would have come into play and that would have caused more friction and more resistance in the movement of cars and automobiles.
The force that resists or slows down the motion of a wheel or a ball (the curved surface) rolling on the ground. When one body is said to be rolling on another body or surface, ideally it is assumed that there is no slipping or sliding. Rolling friction is a weak force, which explains the reason why it is easier to pull an almirah with wheels in it. It is so weak that the magnitude of rolling friction is negligible as compared to static, kinetic, or limiting friction. Rolling friction is often a combination of several types of frictions acting between the point of contact of the curved surface and the ground.