A modern passenger car may look like a machine built mainly from steel, aluminum, glass, and plastic. Yet a closer examination reveals a much more complicated material mix.

Researchers at Chalmers University of Technology, working with Volvo Cars, have mapped the materials found in vehicles to better understand how those choices affect environmental performance and the use of resources.

More Than the Main Materials

Steel and aluminum make up most of the metal weight in a car, but they are only part of the picture. The research found that a highly equipped vehicle could contain 55 different metals and metalloids. Iron and aluminum together represented about 90% of the metal mass examined, while many other elements appeared in tiny quantities.

Those smaller amounts should not automatically be considered unimportant. Some materials have specific jobs that are essential to how a vehicle operates. Copper, for example, can be found across more than 700 components, particularly in electrical wiring. Other elements are added to steel to provide particular material properties needed for vehicle construction. This means a vehicle can contain a surprisingly broad range of materials even when only a handful account for most of its physical weight.

Why Tiny Amounts Matter

One of the key findings from the research is that material quantity and resource importance are not always the same thing. A material present in only a few grams can still influence an assessment of resource use. Gold and other less abundant elements provide an example. Their quantities in an individual vehicle may be very small compared with steel or aluminum, but their contribution can become much more visible when researchers examine long-term resource scarcity.

This creates a challenge for studies that group many materials into broad categories. Such an approach can still provide useful information for certain environmental measurements, but it may hide the role of individual elements that matter from a resource perspective.

Better Data Gives a Fuller Picture

The study emphasizes the importance of detailed material information in life cycle assessment. These assessments are used to examine environmental effects across different stages of a product's existence. When the available data is highly detailed, researchers can ask more specific questions about which materials contribute to particular impacts. When materials are combined into broad groups, some of that information disappears.

According to the research, the difference is not simply about making an assessment more precise. The level of detail also affects which questions the assessment can answer. For the automotive industry, that information could support decisions involving vehicle design, material selection, recycling, and supply chains.

How Vehicle Materials Have Changed

The researchers also compared vehicles from the 2012, 2016, 2020, and 2024 model years. Across those vehicles, the weight of the examined parts increased by roughly 20%. At the same time, the climate impact associated with producing those materials increased by about 42%. The researchers identified greater use of aluminum as one important factor behind that change.

Interestingly, the overall picture for long-term resource scarcity changed much less during the same period. However, the materials responsible for that impact shifted considerably. That difference shows why there is no single measurement that can fully describe the resource consequences of vehicle manufacturing. A material choice may affect one environmental indicator differently from another.

What This Means for Future Cars

The findings point toward a broader way of thinking about vehicle development. Reducing the weight of a particular component or changing one material does not automatically tell the whole story. Designers also need to consider what materials are being introduced, how much is required, where they are used, and what happens to them later.

Detailed inventories could become increasingly useful as vehicles incorporate more electrical systems, advanced materials, and specialized components. Knowing exactly what is inside a vehicle can help manufacturers identify opportunities for more efficient material use and better recycling strategies.

For drivers, the research offers a simple but important insight: a car's material footprint cannot be judged by its largest components alone. Behind the familiar steel and aluminum is a much more diverse collection of elements, each serving a particular purpose.

The study ultimately highlights why vehicle sustainability is a multi-dimensional issue. Looking only at vehicle weight, emissions, or a single material category can leave important details out of the picture. As automakers develop future generations of vehicles, understanding the full material composition could help guide decisions about design, production, recycling, and long-term resource management.