Mass transit has been part of the urban scene in the United States since the early 19th century. Regular steam ferry service began in New York City in the early 1810s and horse-drawn omnibuses plied city streets starting in the late 1820s. Expanding networks of horse railways emerged by the mid-19th century. The electric streetcar became the dominant mass transit vehicle a half century later. During this era, mass transit had a significant impact on American urban development. Mass transit’s importance in the lives of most Americans started to decline with the growth of automobile ownership in the 1920s, except for a temporary rise in transit ridership during World War II. In the 1960s, congressional subsidies began to reinvigorate mass transit and heavy-rail systems opened in several cities, followed by light rail systems in several others in the next decades. Today concerns about environmental sustainability and urban revitalization have stimulated renewed interest in the benefits of mass transit.