For this blog post, I created a map that features major US cities that are in close proximity to interstate highways. In creating this map, I clipped the US interstate shapefile to the Major US cities shapefile. I set the parameters so that the US cities remaining on the map were within 20 miles of an interstate. As the interstate highway system is extensive in the US, there are numerous cities that fall within 20 miles of an interstate. The interstate highway system appears to be densest in the midwest and northeast, and there are many cities that fall within close proximity to highways in this area. Interstates are most dispersed in the middle of the country, and cities in this area are also less concentrated.
In addition to the US major cities shapefile and the US interstates shapefile, I also added a layer to this map from the Living Atlas called “2018 USA Population Density.” By looking at interstates in relation to population density in the US, it is noteworthy that the areas with the highest population density appear to be the areas where the greatest number of interstates intersect. Based on this map, it appears that the areas with the highest population density, the largest US cities, have the greatest demand and require the greatest flexibility in terms of transportation, and consequently these areas have the greatest number of interstate highways.
One main question arose when looking at this map: did the interstate connect these cities, or where there cities established because of the need for breaks in transportation along the interstate? If I were to work with this data more, this is what I would be interested in exploring.