Freight Transportation System Extent & Use

System Extent  |  Freight Flows  |  System Use

System Extent

Miles of infrastructure by transportation mode

Freight travels over an extensive network of highways, railroads, waterways, pipelines, and airways. Road infrastructure increased 6.0 percent while traffic volume increased 17.9 percent, from 2,747 billion to 3,262 billion vehicle-miles traveled, over the 2000 to 2019 period. During that time, the total miles of gas pipeline mileage increased by 22.2 percent while Class I rail miles declined by 23.5 percent.

Freight intermodal connectors on the National Highway System by state

Intermodal connectors provide access between major intermodal facilities, such as ports and truck/pipeline terminals, and the National Highway System (NHS). Although freight intermodal connectors account for less than 1 percent of total NHS mileage (2,593 miles in 2022), they are vital for truck movement. Texas has the highest number of freight intermodal connectors (97), followed by Ohio (65).

National Network for conventional combination trucks

The National Network (NN) was established by Congress in 1982 to facilitate interstate commerce and encourage regional and national economic growth by requiring states to allow conventional combination trucks on the Interstate System and portions of the Federal-aid Primary System of highways. The NN, which has not changed significantly in three decades, differs in extent and purpose from the National Highway System (NHS). Both are about the same length, roughly 200,000 miles, but the NN includes approximately 65,000 miles of highways beyond the NHS, and the NHS includes about 50,000 miles of highways that are not on the NN. The NN supports interstate commerce by regulating the size of trucks, while the NHS supports interstate commerce by focusing federal investments.


Permitted longer combination vehicles on the National Highway System

Longer combination vehicles (LCVs) include truck tractors pulling a long semi-trailer plus a short trailer (often called a Rocky Mountain Double), a long semi-trailer and a long trailer (often called a Turnpike Double), or a short semi-trailer and two trailers (called a Triple). Although all states allow conventional combinations consisting of a 28-foot semi-trailer and a 28-foot trailer, only 14 states and 6 state turnpike authorities allow LCVs on at least some parts of their road networks. Allowable routes for LCVs have been frozen since 1991.


Truck parking facilities by state

The 2014 Federal Highway Administration’s truck parking survey indicates that demands for truck parking spaces exceed supply, and projected increases in freight volume and a likely increase in the number of trucks may exacerbate the problem. Trucks moved nearly 11.3 billion tons of goods, or 60.8 percent of total freight shipments, in 2018. That figure is projected to climb to 14.8 billion tons by 2045, an estimated 31.0 percent increase, according to the Freight Analysis Framework.

The survey also indicated that most states reported an increased shortage of truck parking spaces at public facilities. Public parking facilities are typically located at state rest areas and welcome centers and offer few amenities. Of the 308,920 truck parking spaces available, 88.3 percent were provided by private truck stop operators. The survey noted that 37 states had truck parking shortages at all times throughout the week, and more than 75 percent of truck drivers reported having difficulty finding safe and legal parking during rest periods required by Federal Hours of Service regulations. That number increased to 90 percent at night when drivers often must wait for their drop-off destination to open and accept deliveries. The shortage of truck parking facilities has major highway safety implications for both truck drivers and other highway users.

Number of trucks, locomotives, rail cars, and vessels

Between 2010 and 2020, the number of trucks and vessels increased by 25.2 and 11.6 percent, respectively, while the number of Class I freight rail cars has continued to decline due to improved utilization and the deployment of larger cars.

System Extent  |  Freight Flows  |  System Use

Freight Flows

Freight flows by highway, railroad, and waterway

Trucks carry most of the tonnage and value of freight in the United States, but railroads and waterways carry significant volumes over long distances. Rail transports a large volume of coal between the Powder River Basin in Wyoming and the Midwest, while inland waterways move a substantial volume of freight primarily along the lower Mississippi River.
 Freight flows for highway, railway, and waterway systems in 2018

Average daily long-haul truck traffic on the National Highway System

Long-haul freight truck traffic in the United States is concentrated on major routes connecting population centers, ports, border crossings, and other major hubs of activity. Except for Route 99 in California and a few toll roads and border connections, most of the heaviest traveled routes are on the Interstate System.

Long-haul freight truck traffic on the National Highway System is projected to increase dramatically. Projected data indicate that truck travel may increase from 311 million miles per day in 2015 to 488 million miles per day by 2045. 

Major truck routes on the National Highway System

Several routes carry a significant concentration of trucks, either as an absolute number or as a percentage of the traffic stream. High-volume truck routes are those that carry 8,500 or more trucks per day or 25 percent of the total traffic. In 2015, 6,229 miles of the 223,303 miles of the National Highway System were considered high-volume truck routes.

The number of National Highway System miles carrying large volumes and high percentages of trucks is projected to increase dramatically by 2045. Segments with more than 8,500 trucks per day and where at least every fourth vehicle is a truck are estimated to grow from 6,229 miles in 2015 to 12,729 in 2045, an increase of 104.4 percent.

Tonnage of trailer-on-flatcar and container-on-flatcar rail intermodal moves

Different modes of transportation are frequently used in combination to move cargo. The classic forms of rail intermodal transportation are trailer-on-flatcar and container-on-flatcar, and these services are spread throughout the United States. The largest concentrations are on routes between Pacific coast ports and Chicago, southern California and Texas, and Chicago and New York.

Rail intermodal moves in millions of net tons for 2018

System Extent  |  Freight Flows  |  System Use

System Use

Annual vehicle miles traveled by highway category and vehicle type

Freight goods depend heavily on the Interstate System for delivery. Although one-fourth of the miles traveled by all traffic are on the Interstate System, more than one-half of combination truck vehicle miles of travel are on interstate highways.

Share of highway vehicle miles traveled by vehicle type

Despite doubling over the past two decades, truck traffic remains a relatively small share of highway traffic as a whole. In 2020, commercial trucks accounted for approximately 10.4 percent of highway vehicle-miles traveled. Truck tractors hauling semitrailers and other truck combinations accounted for 58.7 percent of commercial truck travel, while single-unit trucks with six or more tires accounted for the remainder.

Commercial vehicle weight enforcement activities

Federal and state governments are concerned about truck weight because of the damage that heavy trucks can do to roads and bridges. To monitor truck weight, nearly 378.4 million trucks were weighed in 2021, about 89.0 percent of which were weigh-in-motion, and 38.5 percent were weighed by static scales.  Less than 1 percent of commercial vehicle weighs resulted in violations.

Top airports by landed weight of all-cargo operations

The top three U.S. airports together handled nearly one-third of the total landed weight of all-cargo operations; they are Anchorage, Memphis, and Louisville. Anchorage is a major international gateway for trade with Asia, and Memphis and Louisville are major hubs for FedEx and the United Parcel Service, respectively. Memphis recorded a substantial increase of 96.8 percent between 2000 and 2021. Louisville had an increase of 119.6 percent, which is substantial. Cincinnati had an increase of 364.6 percent, which is even more substantial, to move into seventh place from nineteenth place. Weight increased by 62.6 percent at the top 25 airports and by 46.5 percent at all airports.

Top 25 water ports by tonnage

Bulk cargo, such as coal, crude petroleum, and grain, moves through ports on the Gulf Coast and inland waterway system. The top 25 water ports by tonnage handled 68.9 percent of the weight of all U.S.-international freight moved by water in 2020.

Top 25 water ports by containerized cargo

The top ports for containerized cargo are located primarily on the Pacific and Atlantic Coasts. In 2020, the top container ports handled 40.9 million TEU. The Ports of Los Angeles and New York together handled 29.1 percent of all container traffic at water ports in the United States.

Number of container terminals with on-dock rail access by select port

All high-volume ports are directly connected to the rail system or have nearby rail facilities. On-dock rail transfer facilities place containers directly on trains, thereby reducing the number of truck and rail drayage trips. Most container terminals have either on-dock transfer facilities within the terminal boundaries or off-dock facilities nearby.

Number of vessel calls by type at U.S. ports

In 2018, there were 922,250 calls at the 49 ports that make up the principal ports by tonnage, dry bulk, and container TEU, which is a 1.5 percent increase over the number of calls in 2015. Container vessel calls increased by nearly 4.4 percent while dry bulk vessel calls declined slightly by 1.3 percent over the 2015 to 2018 period. Dry bulk barges comprised 50.2 percent of all vessel calls.

Number of container cranes at top 25 container ports by TEU

Many container ports use ship-to-shore gantry cranes mounted on rails that run alongside the wharf to unload and load berthed contained vessels. Smaller ports may use mobile cranes, often positioned on the container vessel itself. The number and size of cranes affect the number and size of ships a terminal can handle, which in turn indicate terminal capacity.  The busiest container ports also have the most container cranes.  The Port of Long Beach had the greatest number of container cranes, followed by the Port of Los Angeles and the Port of New York & New Jersey.

U.S. Department of Transportation, Bureau of Transportation Statistics, Freight Facts and Figures (Washington, DC: 2020).

Freight Facts and Figures, developed by the Bureau of Transportation Statistics, is a collection of charts and statistical tables about freight transportation in the United States. These interactive visualizations and tables provide a snapshot of freight movement; the extent, condition, and performance of the freight transportation system; the economic implications of freight movement; and the safety, energy, and environmental impacts of freight transportation.

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