The study claims that the weight reduction potential of high-strength steel is limited to a mere 11 percent because nearly 40 percent of the 26 parts analyzed could not be made any thinner without severely compromising the vehicle's structural integrity. However, it was found that aluminum could be used to slash weight without reducing the vehicle's stiffness or hampering its performance. The Aluminum Association's Transportation Group says that this study, combined with other data, suggests that approximately 525 pounds of weight savings could be realized by using aluminum.
Click here (pdf) for a look at European Aluminum Association's 58-page report, titled "Stiffness Relevance and Strength Relevance in Crash of Car Body Components."
[Source: Green Car Congress, Aluminum in Transportation (pdf)]