Despite the importance of building lighter vehicles , analysts believe most high-volume cars and trucks 10 years from now will be made with roughly the same material content as today. There is reluctance to forecast materials use farther out than 10 years, but using history as a guide, it's unlikely there will be huge changes in materials use even by 2020 unless there is a major new fuel shock or environmental initiative. The primary reason is cost.
Steel is far less expensive than lighter weight alternatives, especially in high-volume production.
But steel also has been steadily improving over the years. Since the mid 1980s new coatings have made steel bodies more rust-resistant and new alloys of automotive steel have been developed that can be made into thinner, lighter structures. Steelmakers also are fiddling with steel chemistry and density to make lighter weight steel structures. That's not to say other traditional automotive materials haven't taken a big hit over the past several decades. Cast iron, zinc die castings and copper radiators have suffered huge losses to aluminum, plastics and magnesium as automakers have moved to chop weight and improve fuel efficiency.