I agree that this is a marketing term, but it was applied in describing this market segment by numerous reputable sources from its onset. Of course, the EPA and DOT were not established at that time, thus it is impossible to have them "define" this class of vehicle retroactively. Today's pony car ancestors are all lumped in with more generic automobile classifications. In summary, I do not think that pony cars belong in the "sports car" classification. Moreover, the "sports" term has been depreciated and is currently used to classify almost anything: sedans, station wagons, ragtops, the now infamous SUVs, etc. —