The plastic, transparent car

"I want to say one word to you. Just one word."
"Yes, sir."
"Are you listening?"
"Yes, I am."
"Plastics."

The Graduate, 1967

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Through the last round of auto shows, I noticed more and more concept cars with transparent body parts. Of course, concept cars are supposed to show off all sorts of crazy design ideas, but these transparent parts were appearing in unexpected places, such as doors and roofs. And I'm not talking about just a transparent panel in the roof, but the full canopy.

The explanation for these clear cars came at the launch of the Chevrolet Volt, where a spokesperson from GE's Plastics division was on hand to answer questions about the car's body. Of course, most people were interested in the hybrid-electric powertrain, but the Volt's body materials are a significant part of the story.

The Volt has transparent panels that run from the windshield all the way down the back of the car. And the visibility issues associated with its high belt line are mitigated by side windows that retain the form of the belt line while stretching below it. I'm not really sure how the windows roll down with this arrangement, but these transparent body parts are made possible through the use of some of GE's advanced plastics technologies.

According to GM's press release, here's how GE's plastics were used in the Volt:

• Roof made with Lexan GLX resins and Exatec Coating Technology
• Rear deck lid and side glazing made with Lexan GLX resins and Exatec coating technology
• Doors and hood made with Xenoy iQ high-performance thermoplastic composites
• Global energy absorber and hybrid rear energy absorbers with Xenoy iQ resins
• Steering wheel and instrument panel with integrated airbag chute made with Lexan EXL resins
• Front fenders made with Noryl GTX resins
• Wire coating made with flexible Noryl resins

GE was already supplying plastics for GM's Saturn brand, so its work on the Volt is not too surprising, from the standpoint of a business relationship. But the plastics are getting more interesting, with strong, clear plastics cladding the roof and sides.

But this isn't just a GM thing--Hyundai got on board with GE Plastics for its Qarmaq concept car. This crossover prototype is notable for using Lexan to extend the side windows down in a swoop through the doors. It also uses a Lexan panoramic sunroof.

Plastics give automotive designers freedom, as the materials can be shaped more easily than steel. Small design houses can more easily create working concept cars, such as the Ford Giugiaro Mustang shown at the 2006 Los Angeles Auto Show. Honda also seemed to be exploring the use of plastics with its jet fighter-like canopies on its recent round of concepts.

Plastics will see increasing use in cars
This sudden interest in plastics isn't just a phase that industrial designers and engineers are going through; there are a number of factors driving it. First, environmental issues are gaining greater visibility, and automakers want to burnish their green credentials. Plastics let automakers reduce the weight of their vehicles, thereby increasing fuel economy.

But it's not just about miles-per-gallon; GE's Xenoy composite, used in the doors and hood of the Volt, is made from 85 percent recycled material. All those plastic bottles you throw into the recycling bin may end up as body panels on your next car.

Another push for plastics in cars is safety. Consumer Reports has worked out a system using lasers to measure the driver's range of view in different cars. As the public takes range-of-view issues into consideration when buying cars, automakers will have to build it into their designs. Pedestrian safety has also become a major goal of governments around the world. There will be more and more legislation governing how cars are built to decrease injury to people who get hit. Hyundai designed plastics into its Qarmaq concept specifically to include pliable surfaces that would cause less harm to pedestrians.

But probably the biggest factor that will drive plastics in cars is the rising price of steel. There was a dramatic price increase in 2004 due to high demand in China. Although steel prices have steadied, they are still going up. Automakers had many years of relatively cheap steel, but now they will have to look to other materials to preserve the bottom line.

Don't worry; cars will still have steel safety cages and airbags to keep occupants safe. And, as has been happening over the last decade, cars will continue to share common platforms, keeping integrity in their engineering. But the ease of forming plastics into nonlinear shapes could allow more distinct model types that appeal to smaller subsets of the buying public.

I think the most likely future scenario is that the majority of cars adopt plastic body panels, as indicated by the recent concepts, while expensive luxury cars continue to use steel.