Mazda is one of the few carmakers to buck the trend of building bigger and heavier cars with every new model generation, with engineers managing to shave up to 100kg from the already small Mazda2 compact car when it released the second generation model last year. The carmaker is determined to continue the trend and expects that by 2011 its entire family of vehicles will have moved to lighter vehicle architectures.

Mazda isn’t the only Japanese carmaker focused on vehicle weight reduction. Honda, Nissan and Toyota have also made lighter cars a top priority as they scramble to boost fuel economy and cut carbon emissions, reports Automotive News. Mazda has committed itself to reducing fuel-consumption by 30% by 2015, while Nissan is aiming to make its fleet 15% lighter on average than its 2005 levels by the same date. Toyota, meanwhile, has set up a committee to investigate methods of reducing vehicle weights by 10%.

Shedding weight, especially on the supplier side, is expensive for carmakers but there are three main areas were the biggest gains can be found. These include using lightweight materials (such as carbon-fiber and aluminum), employing new engineering and design methods, and reducing the overall size of vehicles.

To achieve the significant weight savings, future models will feature increased use of compression-molded and injection-molded plastics, high-tensile steel, magnesium and carbon fiber. Components, such as air-conditioning systems and seats, can also be redesigned to be smaller and lighter.

Cost is currently the main constraint. Aluminum, magnesium and carbon fiber are much more expensive than steel, which itself is proving to be extensive as demand for the material increases.