According to the International Organization of Motor Vehicle Manufacturers, 97.3 million vehicles were produced in 2017, a 2.36% increase compared to 2016.
On average, 900 kg of steel is used per vehicle. The steel in a vehicle is distributed as follows:
Advanced high-strength steels (AHSS) are now used for nearly every new vehicle design. AHSS make up as much as 60% of today’s vehicles body structures making lighter, optimised vehicle designs that enhance safety and improve fuel efficiency.
The global transportation industry is a significant contributor to greenhouse gas emissions and accounts for about 24% of all man-made CO2 emissions (International Energy Agency, CO2 Emissions from Fuel Combustion Highlights, 2018 Edition, p 13). Regulators are addressing this challenge by setting progressive limits on automotive emissions, fuel economy standards or a combination of both. Many of the existing regulations began as metrics to reduce oil consumption and focused on extending the number of kilometres/litre (miles/gallon) a vehicle could travel. This approach has been extended into the regulations which now limit GHG emissions from vehicles.
Extending the fuel economy metric to meet objectives to reduce emissions is having unintended consequences. Low-density alternative materials are being used to reduce vehicle mass. These materials may achieve lighter overall vehicle weights, with corresponding reductions in fuel consumption and use phase emissions. However, the production of these low-density materials is typically more energy and GHG intensive, and emissions during vehicle production are likely to increase significantly. These materials are often not able to be recycled and need to be sent to landfill. Numerous life cycle assessment (LCA) studies show how this can lead to higher emissions over the entire life cycle of the vehicle as well as increased production costs.
A key factor in understanding the real environmental impact of a material is its LCA. An LCA of a product looks at resources, energy and emissions from the raw material extraction phase to its end-of-life phase, including use, recycling and disposal. worldsteel's publication 'Steel in the circular economy: A life cycle perspective' explains how applying a life cycle approach is crucial to understanding the real environmental impact of a product.