In the 1960s, plastic began to be used more extensively in the automotive industry. Its use has grown significantly since the 1990s, providing enormous reductions in weight, greater fuel economy and increased flexibility in designs, enabling smoother and bolder bodylines. Today, cars have on average >50 kilograms of parts and accessories (interiors, exteriors and even engine bay parts) made from plastic, which substitute around >350 kilograms of steel.