Legislation passed in the 1950's to fund an interstate highway system primarily in response to what?

Legislation passed in the 1950's to fund an interstate highway system primarily in response to the need to be able to land large aircraft in emergencies. 

Contributing factors  leading  to the harlem renaissance were the great migration of african americans to northern cities, which concentratedambitious  people in places where they could encourage each  other, and the first world war, which had created new industrial work opportunities for tens of thousands of people.