Variance in Transportation Infrastructure by US State

State Similarity Index - Infrastructure Category - Transportation

The State Similarity Index attempts to quantify how similar US states are to each other. The index is a statistically-based way to measure this. 20% of the index is based on infrastructure. 16.66% of a state’s technology score (3.33% of the overall State Similarity Index score) is allocated for the state’s transportation infrastructure. The following factors were included in the calculation:

Road Density

In general states with higher population densities also have a greater amount of roads per square mile as a result. Rhode Island and New Jersey, two states in the BosWash region, are the two most densely populated. They also have the densest network of roads. One exception is Hawaii. Since it has dense forests and hilly terrain, its land is more difficult to build on. Honolulu has many high-rises that concentrate the state’s population within a small footprint. States in the Western portion of the United States have a lower density of roads. Not only are these states less densely populated, a lot of their people are concentrated in large cities, so their rural areas are not as populated. Unsurprisingly, the least densely populated state, Alaska, has the lowest road density as well.

Bureau of Transportation Statistics

States were categorized by miles of public road per square mile:
0-75, 75-150, 150-225, 225-300, 300-375, 375-450

Road Condition

California has the worst roads have any state, despite its people having a relatively high income per capita. When accounting for the amount of vehicle miles traveled, California spends proportionately less than other states. New Hampshire, on the other hand, has the smoothest roads, according to the International Roughness Index. However, Rhode Island another state in New England, has the second worst roads after California. There does not seem to be much correlation between the condition of roads in a state and the region it is in.

Money Geek

States were categorized by the International Roughness Index of their roads:
71-83, 83-95, 95-107, 107-125, 115-143, 143-161

Road Salt

Road salt is commonly used during winter months in certain regions of the United States to mitigate ice and snow buildup on roads, thereby improving driving safety. States in the Midwest and Northeast, known for their cold and snowy winters, tend to use the most salt. In contrast, states like Oregon and Washington, despite being located in the north, generally experience milder winters due to the coastal climate influenced by the Pacific Ocean. Additionally, states in the Rocky Mountains often receive dry snow, which is less prone to forming ice compared to wet snow. Dry snow has lower moisture content, requiring less salt for effective melting and prevention of ice formation on roads.

Database for the characterization and identification of the sources of sodium and chloride in natural waters

States were categorized by the amount of road salt used each year:
0-50, 50-100, 100-250, 250-500, 500-750, 750+

Railroad Density

Unlike road density, railroad density is less correlated with population density. In fact, Indiana is the state with the highest density of railroads. This is due to historical manufacturing and industrial activity, its central location as a transportation hub, and the transportation of agriculture and natural resources. In contrast, Hawaii does not have any active railroads that are not just tourist attractions. It is an isolated group of island in the middle of the Pacific Ocean, so shipping is more convenient.

Bureau of Transportation Statistics

States were categorized by miles of railroad per square mile:
0-2, 2-4, 4-6, 6-8, 8-10, 10-12

Railroad Operator

There are various companies that operate the railroads in the United States. BNSF and Union Pacific operate primarily west of the Mississippi, while Norfolk Southern and CSX operate east of the Mississippi. These Class 1 railroads connect major cities, ports, and industrial areas, providing essential transportation services for the movement of goods and materials across the United States. In New England, many of the tracks are operated by Genesee & Wyoming, a short line and regional railroad company.

American Association of Railroads

Major Railroad Operators:
BNSF Railway
Canadian National Railway
CSX Transportation
Norfolk Southern Railway
Union Pacific Railroad
Genesee & Wyoming

Vehicles per Capita

Rural states in especially in the West, tend to have the most vehicles per capita. Wyoming is the state with most. It has a vast land area and limited public transportation options. Owning multiple vehicles is common in Wyoming. In contrast, New York has the least number of vehicles per capita. This is due to the fact that many of its people live in New York City and rely heavily on subways, busses, walking, and cycling. High costs associated with vehicle ownership, including parking fees and insurance, deter residents from owning a personal vehicle, leading to a lower overall vehicle count in the state.


States were categorized into the following groups by vehicles per 1,000 people:
500-600, 600-700, 700-800, 800-900, 900-1000, 1000-1100

Public Transit Ridership

In many rural states, less than 1% of people commute using public transportation. Few public busses operate regularly in these states and the vast majority of people have cars. New York has the highest percentage, since many people live in New York City, the largest city in the United States. It has a plethora of public transportation options. Many people in New Jersey also use public transportation, since a large percentage of its population is also in the New York metropolitan area. New Jersey has two subway tunnels that connect directly to New York.

Bureau of Transporation Statistics

States were categorized into the following groups by commute mode share:
0-1.66%, 1.66-3.33%, 3.33-5%, 5-10%, 10-20%, 20-30%

Airplane Passangers per Capita

Nevada and Hawaii have the highest percentage of airplane passengers per capita due to several factors. Nevada is home to Las Vegas, a major tourist destination known for its vibrant entertainment industry. Hawaii is a remote island state, and air travel is often the primary mode of transportation for visitors and residents alike to travel between the islands or to and from the mainland United States. Additionally, Hawaii’s economy is heavily reliant on tourism, with millions of visitors arriving by air each year to enjoy the state’s beautiful beaches, stunning landscapes, and unique culture.

Bureau of Transportation Statistics

States were categorized into the following groups by passangers per capita:
0-.75, .75-1.50, 1.5-2.25, 2.25-5.5, 5.5-7.75, 7.75-10

Amtrak Passangers per Capita

The BosWash region, spanning from Boston to Washington D.C., uses passenger rail service the most in the country. This densely populated corridor is one of the few areas in the country where regular passenger train service is available. The residents of Delaware and Rhode Island rely on it the most, since they are located in between major cities. Although most states in the U.S. have at least one Amtrak stop, there are a few exceptions. States such as Hawaii, Alaska, South Dakota, and Wyoming do not have Amtrak service.


States were categorized into the following groups by passangers per capita:
None, 0-.075, .075-.15, .15-.4, .4-.65, .65-.9

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