To enable greater visibility, your car’s side mirrors use curved glass called convex. Though convex glass provides a better field of vision, it gives an inaccurate representation for distance – things look further away.
Even with convex glass, you still can’t always see everything in your side mirrors. There’s certain areas that you sometimes have to physically look over your shoulder to check. These areas are called blind spots. To keep the blind spot areas to a minimum, it’s important to adjust the side mirrors for maximum visibility.