As requirements for fuel efficiency and recyclability of autos become more stringent, the auto industry could benefit from using lighter-weight materials, according to a report from consultancy Frost & Sullivan, Palo Alto, Calif. "Lightweight materials such as plastic are ideal to improve fuel efficiency and design flexibility without compromising on performance or safety," says Sathyaraj Radhakrishnan, research analyst. "Reduced tailpipe emissions and improved corrosion resistances are some of the other added benefits of lightweight materials." In terms of fuel efficiency, a 10% reduction in vehicle weight can improve fuel usage by 6% to 8%. In addition to plastics, magnesium alloy, which is two-thirds the density of aluminum and one-fourth that of iron and steel, is making inroads into the auto industry, according to Frost & Sullivan. Additionally, magnesium alloys are recyclable. In 2005, the European Union will require all cars to be made of 85% recyclable materials.