Those diagonal irons on the rear quarter panel of hearses are called “landau bars.” They are purely decorative today, but they once served a purpose and are now in place as a nod to history.
The landau carriage was invented in Germany in the mid-18th century. Lightweight and suspended on elliptical springs, this four-in-hand coach was a precursor to today’s convertible cars in that it had a collapsible roof. The soft folding top on the original model was divided into two sections, front and rear, which were latched in the center. An elongated external hinge mechanism was necessary to support the folding roof, and since the pricey landau was designed as a luxury vehicle for the upper classes, designers added the elegant S-shaped scroll to the utilitarian hinges to make them more aesthetically appealing.
Early horse-drawn hearses were carriages that often featured fully functional landau bars. Before World War II, American automobile hearses borrowed the landau bar flourish as an homage and an attempt to add a touch of Old-World "class." Over the years the landau bars became so ingrained in the public’s mind as a symbol of a funeral car that most hearse manufacturers still tack them onto their limousines as a matter of tradition.