Abstract
To achieve better fuel economy, automakers are seriously considering vehicle weight and size reduction. This is achieved by using lighter-weight materials like high-strength steel and aluminum, better vehicle design, and offering smaller vehicle models. To consider the effectiveness of these approaches, it is important to take into account the dynamic life-cycle energy and environmental impacts. For instance, primary aluminum requires almost four times more energy to produce than steel today. Expected efficiency improvements in material processing would modify this ratio over time. Examining the impact of lightweighting on the overall vehicle fleet system- level, as opposed to a single vehicle-level, also reveals insights on the timing and degree of the impact reduction achieved.