The obvious solution is to use lighter weight materials. Numerous manufacturers have dabbled in use of aluminum to various degrees ranging from hoods and trunklids to full structures. However, aluminum is both more expensive and not as strong as steel. The strength issue has been addressed by improved finite element analysis tools that allow structural optimization. One material that has huge potential for weight savings without sacrificing strength is carbon fiber. Carbon fiber has been used in race cars for over two decades due to the fact that it has strength comparable to steel at one-fifth of the weight. Unfortunately it costs 30 times as much as steel. Toray Industries Inc., Teijin Ltd. and Mitsubishi Rayon Co, the three Japanese companies that dominate 70 percent of the carbon fiber market, are trying to crank up production volumes and develop new processes to cut costs. Currently only one percent of carbon fiber output is used for automotive applications and most of that goes to higher performance cars like the Nissan GT-R and the new Corvette ZR1. If carbon fiber could be widely used, it's estimated that the weight of cars could be cut in half.
The combination of slashing the molding times for carbon components and rising steel prices are both coming together to promote the lightweight material. There are still a lot of issues to address, but carbon could play a much bigger part in the future of cars.
[Source: Automotive News - sub. req'd]