Since there was an increase in freeways in 1956, what other industry may have boomed during this era?
agriculture
cars
processed foods
air travel

cars

Explanation:

The construction of the Interstate Highway Network was authorized by the Federal Aid Highway Act of 1956, popularly known as the Interstate and Defense Highways Act of 1956.

It was a petition of the largest automobile manufacturers in the United States and promoted by President Dwight D. Eisenhower - influenced by his experiences as a young soldier crossing the United States in 1919 following the route of the Lincoln Highway and the knowledge of the motorway network German (Autobahnen) during World War II - as a necessary component of a national defense system. This would make possible a better displacement by land of troops and military supplies.

The design of a system of new superhighways began in the late 1930s, even before a federal committee formed to build the Interstate Highway System in the 1950s. In the 1920s, some roads, such as those in the New York area, were built as part of the local or state systems. As car traffic increased, there was a need for an interconnected national system that would complement the existing Federal Highway System of the United States. The publication of the Map of the Location of the Interstate Highway System is informally known as the Yellow Book Yellow Book.

i really really really really really really dont know