According to the U.S. Department of Energy (DOE), despite vehicles getting heavier over the past two decades, they’ve also greatly increased their use of lightweight materials. The average weight of a light passenger vehicle in North America has increased from about 3,700 pounds to about 4,000 pounds from 1995 to 2014. Yet that weight gain would have been far larger were it not for the roughly 300 pounds of standard steel per vehicle that’s been removed in favor of lighter materials such as high strength steels, aluminum, etc.
Much of the weight loss has been in the reduction of iron castings (cast iron) in vehicles, which has largely been dropped thanks to engines moving to aluminum architecture. Aluminum use in the average light duty vehicle has increased 72 percent in 20 years.
Plastics and composites have also seen an increase in use, jumping 40 percent in that same time period.