In what year was the interstate highway system established?

Answer: D — 1956

The year the interstate highway system was established is 1956. This landmark legislation, known as the Federal-Aid Highway Act of 1956, was instrumental in creating a network of highways that facilitated interstate travel and commerce across the United States. The act aimed to construct approximately 41,000 miles of the interstate highway system, improving road safety and reducing travel times. The establishment of the interstate system was a significant development in American transportation, as it provided a structured way for the nation to connect major cities and states. This also helped in the economic growth of the country by enabling faster and more efficient movement of goods and people. The infrastructure laid down by the 1956 act continues to play a crucial role in the U.S. economy and transportation system today.