What was one effect of the interstate highway act of 1957? the emergence of the car as america’s main mode of transportation the creation of speed limits as a result of increased highway accidents the sluggish development of the airplane industry an increase in the populations of midwestern and western cities fewer jobs because the railroads lost business.

The correct answer is D) an increase in the populations in the Midwestern and Western cities.

One of the effects of the Interstate Highway Act of 1957 was an increase in the populations in the Midwestern and Western cities.

The importance of the Highway Act of 1957 is that it allowed the construction of nearly 40,000 miles highway system in the United States, that spread throughout the nation. One of the effects of the Interstate Highway Act of 1957 was an increase in the populations in the Midwestern and Western cities. It created jobs for the construction of this vast system of highways, taxes help with the money for constructions and the new ways helped people to get to different parts of the countries in less time.