Currently the term "retro design" is being used for cars that re-propose the up-to-date general aesthetic planning of an already existing past model. The most successful examples of this kind are the Volkswagen Beetle, the Mini and the Fiat 500, while in the US the current ones are the Ford Mustang, the Dodge Challenger and the Chevrolet Camaro, however the 2002 model of Ford Thunderbird is not produced any more. Retro design causes fierce arguments among design professionals. Some of them maintain that these products cause complications to the automobile industry; the new economic car releases of past models have nothing to do with the "Spartan" austerity of the original ones and thus, are positioned differently than their predecessors. They are too expensive and are just mere stylistic-stretching resulting in inadequate space and unsatisfactory aerodynamics. What's more; being connected to concrete models, they become quite hard to be stylistically evolved as time goes by, putting serious constraint on new ideas.
According to my personal point of view the re-introduction of historic models neither means turning back, nor going against progress.
I believe that these researches open exciting foci of perspective, that is: retro cars are not copies of their predecessors or renovated specimen, rather they are carefully studied reconsiderations of models strongly rooted in contemporary style. They are interpretations obtained via a creative process, similarly to any new models. Hypothesized objects planned for the future telling stories of the past.
The critics speaking of "epidemics" tend to forget that in the total annual production of the entire automobile industry the "retro" projects remain under 2%. Any model remains, on average, 6-7 years in the market with at least one stylistic intervention at half-term of its career. The VW New Beetle has been produced for 15 years with a slight stylistic updating in 2005. The Fiat 500 has been facelifted for the first time after 8 years of production. It's as if to say that the retro models, having already aged or being dead seem to be more resistant of time.
Regarding the phenomenon from the designer's point of view, we may discover that "retro" as such, does not even exist. The designers of any new car always try to create models by maintaining stylistic continuity with the rest of the production of the same brand, recycling, re-proposing and reconsidering features of previous models. The example perfectly illustrating the above logic is that of the Porsche 911, which throughout 50 years undergoing an imperceptible evolution of perpetual changes, has always remained the same. Comparing the first 911 model with that of today, this latter is but a retro model, the up-to-date reinterpretation of the 911 of 1963. It's all just a matter of continuity that in the case of Porsche 911 has always been unchanged, while in case of the Mini, the 500, the Beetle and some others, the process was interrupted and restarted after long decades.