The automobile is a four-wheeled motor vehicle designed primarily for passenger transportation and commonly propelled by an internal combustion engine using a volatile fuel. Its design involves a chassis, body, interior, powertrain, and steering and braking systems. The chassis is the structural system that supports the body, which holds the passengers and cargo. The powertrain is the mechanical system that converts the energy of the gasoline into the motion of the wheels. The interior is the compartment that holds the passengers, and the steering and braking systems are the control systems that manage the automobile’s movement. The automotive industry has evolved significantly over the years, and new automobiles are continuously being introduced to the market.
Automobiles are a valuable form of personal transportation, but they can also be dangerous. The most serious dangers from automobiles are accidents and injuries. There are also concerns that automobiles contribute to air pollution and global warming. Many cities have public transportation systems such as buses (steam-powered, diesel-powered or monorail), trams or subways that can get people where they are going more quickly and cheaply than automobiles.
The era of the annually restyled road cruiser ended with federal standards for automobile safety, emissions and fuel efficiency; with rising gas prices after the oil shocks of 1973 and 1979; with competition from the German Volkswagen “Bug” and then Japanese manufacturers of functionally designed, well-built small cars. These developments forced automobile companies to invest more in research and development. This, in turn, required more capital and fewer small producers, and the number of active automobile makers dropped sharply.