A streetcar suburb is a residential community whose growth and development was strongly shaped by the use of streetcar lines as a primary means of transportation. Such suburbs developed in the United States in the years before the automobile, when the introduction of the electric trolley or streetcar allowed the nation's burgeoning middle class to move beyond the central city's borders. Early suburbs were served by horsecars, but by the late 19th century, cable cars and electric streetcars, or trams, were used, allowing residences to be built farther away from the urban core of a city. Streetcar suburbs, usually called additions or extensions at the time, were the forerunner of today's suburbs in the United States and Canada. San Francisco's Western Addition is one of the best examples of streetcar suburbs before westward and southward expansion occurred.
Although most closely associated with the electric streetcar, the term can be used for any suburb originally built with streetcar-based transit in mind, thus some streetcar suburbs date from the early 19th century. As such, the term is general and one development called a streetcar suburb may vary greatly from others. However, some concepts are generally present in streetcar suburbs, such as straight (often gridiron) street plans and relatively narrow lots.
