For a variety of reasons, cars have been getting heavier. A standard-size Chevrolet, for example, weighed about 3,700 lb in 1963 and 4,600 lb in 1973. Since there is a direct correlation between vehicle weight and gas mileage (EPA figures show an average of 24 mpg for a 2,000 lb car vs 11 mpg for a 4,000 lb car), weight reduction becomes an attractive means of increasing gasoline mileage. Also it can often be accomplished without compromising comfort and safety features.To help cope with the energy dilemma, more efficient use of gasoline in cars is needed. Aluminum, with a proven track record in weight reduction in cars and all other transportation vehicles, offers an ideal solution to auto weight problems.Immediate primary weight saving of 1.5 lb can be obtained by substituting a single pound of aluminum in place of auto parts made of traditional materials. This saving also permits use of lighter structural supports-again adding to the weight saving.