Alcoa believes that government fuel standards and customer demand for better mileage will push car makers to use more lighter materials like aluminum. Some drivers think heavy vehicles are safer in a crash â¿¿ truck sales were a major factor in the strong March figures â¿¿ but Kleinfeld argued that lighter cars can brake to a stop faster, potentially avoiding accidents.Sales of aluminum for nonresidential construction is finally recovering in North America and will grow much faster in China, Kleinfeld said. Alcoa released its earnings after the markets closed. Its shares rose 15 cents to close at $8.39 in the regular session. They fell 12 cents in after-hours trading.