IT'S all in the concept. When the auto show in Detroit opens this weekend, people will have the chance to gawk at more than a dozen so-called ``concept cars,'' one of the largest displays of futuristic automotive mock-ups assembled.
These crowd-stoppers have been around for decades. At the 1938 New York World's Fair, patrons thrilled to see models of flying cars that the auto industry promised would one day help solve rush-hour tangles.
Concept cars are meant to tease the public and create an image of leadership for a particular car company. They also give designers an outlet for their own creative juices, allowing them to stretch beyond the narrow confines of production automobiles.
``They're pep rallies for us internally, a chance for us to say `yes' to new ideas,'' says Terry Henline, chief exterior designer with General Motors Corporation's Pontiac Division.
Each of the GM divisions will design and exhibit at least one concept car this year, notes Chuck Jordan, the automaker's corporate design chief.
``We have one overriding goal: to reaffirm our design leadership,'' he says. ``There's been so much GM bashing ... it's important the public get the idea things are happening here.''
GM won't be alone, however. The Ford Motor Company, the Chrysler Corporation, and many Japanese and European automakers also plan to display advanced concept cars in Detroit and at subsequent auto shows around the country.
Often distinguished by their exercises in excess, their flowing lines typically better suited to the set of a science fiction movie than a highway, concept cars are usually made of clay, fiberglass, or even wood. Many have smoked or translucent windows to hide their missing interiors.
Among the more unusual designs to grace recent auto shows were the Volkswagen Scooter, a cross between a motorcycle and a passenger car, and Chrysler's Slingshot, a jet-like dune buggy.
Though this year's concept cars will also stretch the imagination, a subtle change has begun.
More and more, concept cars are being used as advanced test beds for breakthrough designs and technological developments that may one day show up on the vehicles the public drives.
Last fall, during a preview of the division's 1989 models at the race track in Watkins Glen, N.Y., Pontiac engineers allowed reporters to drive several running concept cars, including the Banshee, a low-slung sports car prototype.
But the Banshee isn't as far-out as it first appears, despite its sci-fi shape. In fact, company sources admit, many of the styling concepts that made it one of the most popular mock-ups on the Auto Show circuit will appear on the next generation of the sporty Pontiac Firebird coupe, a remake of the production car due to debut in the early 1990s.
And that translation isn't all that's unique these days. In the early 1980s, people at auto shows gawked at the oddly aerodynamic styling of the Ford Probe III, ``which turned out to be the forerunner of the Sierra,'' a European-made sporty coupe that is sold in the United States as the Merkur XR4ti, notes Jack Telnack, head of Ford's worldwide design operations.
``We at Ford are not doing those blue-sky ... dreams in chrome cars anymore that are just someone's fantasy,'' Mr. Telnack says. ``A designer can't think that way anymore, even when doing a concept car. [Designers] are so much more functionally oriented. That's why the concept cars are more real now.''
Concept cars give an automaker the opportunity to prepare the public for what is coming. It also gives designers the chance to prepare their corporate bosses.
``We also use these vehicles to condition management,'' Telnack explains. ``It's very difficult to come in and approve a model with new sculpturing concepts they've never seen before.''