Do you like to travel? Everyone loves a vacation, right? Sometimes you might take an airplane to get wherever you're going. At other times, though, you may pile in the family vehicle with your siblings, friends, and family members for a good old-fashioned road trip!

If you do much traveling by car, you've probably noticed that you travel faster and get to places quicker on certain roads. Some roads are narrower with lots of traffic and stop signs. These local roads might pass through many small towns along the way.

Other roads are wide with higher speed limits. There are no stops and you can go great distances in a much shorter time. What are we talking about? Interstate highways, of course!

Interstate highways are part of what is officially known as the Dwight D. Eisenhower National System of Interstate and Defense Highways. More commonly, these freeways that stretch in every direction across the United States for a total of over 47,000 miles are known as the Interstate Highway System or simply Interstates.

The Interstate Highway System is named after President Eisenhower, who believed a reliable system of freeways was necessary for the economic development and defense of the U.S. The Federal-Aid Highway Act of 1956 authorized construction, which was completed over the course of the next 35 years.

Although interstate highways are often the quickest way to get from one state to another, they are also often the quickest way to get from one point to another within a single state. In fact, some interstate beltways, or loops around major cities, don't connect to other states at all.

Interstate highways do offer many benefits to the defense of the U.S. They allow for easy evacuation in the case of widespread emergencies. Moving military troops and equipment from one part of the country to another is made much easier and quicker by the Interstate Highway System. Many parts of interstate highways are so long and straight and wide that they can also be used to land planes in case of an emergency.

More important than defense, though, economic development was spurred by making it easier to travel and ship goods from one part of the country to another. The Interstate Highway System allowed large cities to grow, while also enabling people to move to areas farther away from the city and commute to work.

The Interstate Highway System uses a unique numbering system. North-south interstates have odd numbers, while east-west routes have even numbers. The lowest numbers are located in the west and the south. Beltways and loops around cities have three-digit numbers.