In simplistic terms, sports-prototypes are 2-seat racing cars with bodywork covering their wheels, and are as technically advanced and, depending on the regulations they are built to, as quick as or quicker than their single-seat counterparts. Although not widely known sports-prototypes  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.

       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. DP chassis are subject to a franchise-like approval system in which only approved constructors are eligible, although this has led in 2007 to Lola and Dallara entering the  series by taking over the rights of existing constructors .