Automobiles are self-propelled vehicles that can be used on road, track, and water. They usually have four wheels, and are primarily designed to transport passengers, but they can also carry cargo.
The first modern automobiles appeared in the late 1800s. Initially, these cars were powered by steam engines. Their range was limited, and they required significant effort to start. Eventually, steam engines were replaced by gasoline-powered engines.
After World War II, the automobile industry exploded in the U.S. With the advent of the Model T, automobiles became affordable for middle-class families. A mass-production system enabled manufacturers to compete and create better vehicles.
Today, automobiles can be powered by gasoline, electricity, or solar cells. They may have four or more wheels, and have seats for two to eight people. However, the definition of the term automobile is often a bit more general. It is used to include other types of vehicles, such as trucks, buses, and trains.
As of 2010, the United States has stricter limits on emissions of hydrocarbons and nitric oxides from motorcycles. These emissions must be less than 5.0 grams per km.
There are many different types of motor vehicles, such as bicycles, quads, and mopeds. Some types of automobiles are small, easy to ride, and have two speeds. Others have more room and seat more people.
In the early 1900s, electric cars had a large share of the automobile market in the U.S. But the range was limited, and charging stations were hard to find. Fortunately, these days, the majority of electric vehicles have an electric push-button starter.