It is widely believed that when president eisenhower signed a bill to create a national interstate highway system in 1956, he did it for what primary purpose?

D)to provide the means to transport military aid more quickly in the event of a national military crisis

Explanation:

It is widely believed that President Eisenhower signed the "National Interstate and Defense Highways Act" into law in 1956 to provide the means to transport military aid more quickly in the event of a national military crisis. This is not the ONLY reason he signed the bill into law, but it did have an enormous impact in the bill's drafting and passage. Remember: during the Cold War things were very complicated.