Fender skirts

Fender skirts, known in Australia and the United Kingdom as spats, are pieces of bodywork on the fender that cover the upper portions of the rear tires of an automobile.

Functions
Fender skirts are implemented for both aesthetic and aerodynamic reasons. Rather than air flowing into and being trapped in the rear wheel well, it flows smoothly over the bodywork. They are typically detachable to allow for tire changes. Automakers have also experimented with front wheel fender skirts, as on the 1950-1954 Nash Rambler, but with success limited by the fact that the front wheels must pivot for steering, extending out from the side of the vehicle slightly.

History
First described as "pants", they were used for the streamlining effect by Frank Lockhart on a 1928 Stutz land speed record attempt car. Factory production of fender skirts began with the 1932 Graham-Paige. Aesthetically streamlined designs were copied to mass-produced models. The innovations introduced by Amos Northup, such as the V'd radiators, fender skirts, and sloping beaver-tails, became common after 1933. However, by the 1970s, fender skirts began to disappear from mass market automobiles. Fender skirts remained for some time longer on a few cars, particularly large American luxury cars.

Fender skirts were often paired with whitewall tires. The extent of the skirt also varied, before the 1950s it was common for all but the very bottom of the rear tire to be covered, while by the 1960s fender skirts only covered some of the top of the tire, and were largely absent afterwards. For example, up until 1996, the Chevrolet Caprice, Oldsmobile 98, Buick Skylark, Oldsmobile Achieva, Buick Roadmaster, Cadillac Deville, Cadillac Fleetwood, and General Motors EV1 all had fender skirts. However, most of these models were eliminated after 1997 (Although the Deville name survived, but was redesigned and the fender skirts were removed).

In European automobile design, Citroën notably used fender skirts on nearly all models produced between 1950 and 1990, most prominently in the DS, 2CV, Ami, GS, SM, BX and CX.

As of 2009, the last car produced with common fender skirts was the 1999-2006 Honda Insight, although they are available for some new cars as aftermarket accessories.

Some cities, such as Los Angeles, have fender skirts on municipal buses for safety purposes, as they can prevent items in the road from slipping under the tires.