Door hinges play an important role in automobile design. They are part of the door retention component that holds the door in case of impact. These can become worn or damaged from wear and tear, which cause the door to sag. Door sag causes misalignment and can prevent the door from shutting correctly and lead to safety issues. Automotive companies have been performing door sag analyses for a long time now to optimize the door weight and the strength and weight of the hinge components.