legal requirements to be classified as a motorcycle by the U.S. government, or to be driven on the street". Pre-production prototypes are used for testing and evaluation of upcoming designs. These evaluation cars are built early on during a model year, but with some of changes that are going to be incorporated in the manufacture of the next model year models. In the case of American Motors (AMC), these included appearance modifications such as grilles, tail lights, trims, or interiors that were fabricated in clay, fiberglass, wood, or plaster. These experimental vehicles were road tested in anticipation of consumer demand and regulatory changes. Designs were tested in these cars in response to customers and drive reports, as well as to include better solutions like making the ashtray and cigar lighter more user friendly. Automakers put new technologies in endurance or motor sport contests to test their use in extreme conditions before incorporating them in production cars. For example, the electronic fuel-injected (EFI) Rambler Rebels that participated in the 1957 NASCAR Daytona Speed Weeks (held on the Daytona Beach Road Course) were "pre-production pilot cars." However, AMC's supplier, Bendix, was not able to work out all the drivability problems from its "Electrojector" system. Although the EFI option was announced to AMC dealers and described in the Owner's Manual, no 1957 fuel injected Rebels were sold to retail customers. Automakers also design production prototypes to experiment and help develop new standards and regulations. Major safety improvements may be taken into account during the initial development stages of vehicles, but not removed from actual production cars even after the proposed stiffer regulations are rolled back. The AMC Pacer was designed with shortened ends, but incorporated "new impact energy absorbing ideas" to perform at higher crash speeds than the final U.S. regulations that were mandated for the 1975 model year production. Hardware Module Maturity The maturity of the hardware components increases during the pre-production phase until the component reaches production quality (PPAP). The maturity is typically indicated using alphabetic notation (i.e. A,B,C samples), sometimes appended with numerals to indicate the design iteration. See also Automotive design Clay modeling Notes Automotive industry Car models Automotive technologies