Although not widely known sports-prototypes along with Formula 1 cars are responsible for introducing the most numbers of new technologies and ideas to motorsport, including rear-wings, ground effect 'venturi' tunnels, fan-assisted aerodynamics and dual-shift gearboxes. Some of these technologies eventually filter down to road cars.

are a product of the Grand-Am Rolex Sports Car Series, and offer a different interpretation of the prototype theme. DPs, as they are often called, are closed-cockpit, purpose-built racing machines which are less expensive and deliberately somewhat slower than Le Mans Prototypes, which were becoming dangerously quick on the Daytona oval. Compared to the LMPs, DPs are sharply limited in terms of approved technology; for instance, they are required to be constructed of steel tube frames with carbon-fiber skins, rather than being carbon-fiber monocoques, and must use production-based engines. The intention of the DP formula was to provide a class in which tight technical regulations encouraged close competition and where budget would be relatively unimportant.