Weight

During the late 20th and early 21st century cars increased in weight due to batteries, modern steel safety cages, anti-lock brakes, airbags, and "more-powerful—if more-efficient—engines" and, as of 2019update, typically weigh between 1 and 3 tonnes. Heavier cars are safer for the driver from a crash perspective, but more dangerous for other vehicles and road users. The weight of a car influences fuel consumption and performance, with more weight resulting in increased fuel consumption and decreased performance. The SmartFortwo, a small city car, weighs 750–795 kg (1,655–1,755 lb). Heavier cars include full-size cars, SUVs and extended-length SUVs like the Suburban.

According to research conducted by Julian Allwood of the University of Cambridge, global energy use could be greatly reduced by using lighter cars, and an average weight of 500 kg (1,100 lb) has been said to be well achievable.better source needed In some competitions such as the Shell Eco Marathon, average car weights of 45 kg (99 lb) have also been achieved. These cars are only single-seaters (still falling within the definition of a car, although 4-seater cars are more common), but they nevertheless demonstrate the amount by which car weights could still be reduced, and the subsequent lower fuel use (i.e. up to a fuel use of 2560 km/l).