One of the primary concerns with automobiles is ensuring a safe experience for drivers, passengers, and especially pedestrians who account for nearly 16 percent of traffic-related fatalities. Part of minimizing traffic-related deaths is designing vehicles to be durable as to not endanger those inside. In the early 20th century, steel was the primary and most important material in manufacturing as it was less expensive and required less production time while being stronger than alternatives. However, these automobiles were quite heavy and decreased travel speeds. During and after the First World War, companies began to experiment with aluminum in automobile design, which is significantly lighter than conventional steel, more malleable for aerodynamic design, and has minimal losses in durability. Production materials remained rather constant until the 1950s when fiberglass composites were beginning to be used in full production cars. Further fueled by the oil crisis in the 1970s, manufacturers then felt the pressure to design vehicles that were even more lightweight leading to improved fuel-efficiency. Original equipment manufacturers (OEM) understood that certain parts, such as bumpers, could be substituted with plastic alternatives to decrease weight and price. Consequently, many of the heavier parts were swapped with plastic alternatives.
Today, OEMs juggle the increasing demand for more utilities (and heavier designs) while continuing to improve fuel-efficiency. Several companies are experimenting with plastic carbon composites, but widespread production lags due to notably higher costs. For now, high strength steel and certain aluminum alloys prevail as the primary materials used in automobiles, especially in light vehicle production.