transportation system in the United States transformed the economy and the culture of the country. The development of the railroad industry in the late nineteenth century influenced the growth of an interdependent national economy. Railroads stretched across the country and connected every region and major city.

The transportation system has been the single most important driver of American economic and social integration. In the 19th century, the Transcontinental Railroad and the Erie Canal transformed the U.S. from a collection of isolated regions into a unified national market, allowing goods from the Midwest to reach New York City and settlers to reach the West. In the 20th century, the Interstate Highway System, initiated in 1956, revolutionized the landscape by giving birth to the "suburban lifestyle" and the trucking industry, which now moves over 70% of the nation's freight. This infrastructure allowed for "just-in-time" manufacturing and the rise of retail giants like Walmart and Amazon. Furthermore, the development of commercial aviation collapsed the distance between the coasts, making a transcontinental trip a matter of hours rather than months. Today, transportation contributes over 8% to the U.S. GDP and is essential for maintaining the global supply chains that the modern economy relies upon.