"Are we there yet?" is an age-old question that back-seat passengers have been asking for decades. Automotive engineers on the lightweighting journey are faced with a similar quandary.

During the past decade, the average amount of aluminum in passenger cars has doubled. Based on the latest designs, this trend will continue in the coming years.

Ask the typical American about automobile history and you're likely to hear the name "Henry Ford." Pose the same question to a Brit, however, and get ready for an answer of "Morgan Motor Co. (MMC)."

Steel has been, is now, and will continue to be the predominant material for vehicle structures and body parts, such as doors, hoods, liftgates and fenders. But, other materials, such as aluminum, magnesium, plastics and composites, are becoming increasingly important.

Lightweighting is one way that automakers are trying to make vehicles more energy efficient. For every 100 pounds taken out of a vehicle, fuel economy increases by 1 to 2 percent. To cut weight, engineers are incorporating a raft of new materials in vehicle designs, including composites, plastics, aluminum and high-strength steels.

Bulky batteries are the heart and soul of electric vehicles. But, their weight creates numerous challenges that demand lightweight materials.

ZARAGOZA, Spain—Engineers at the Technological Institute of Aragon here are coordinating a new European Union initiative to develop lightweight components for electric vehicles.