Bureau of Transportation Statistics

Special Report

U.S. Department of Transportation

Research and Innovative Technology Administration SR-002

July 2007

A Decade of Growth in Domestic Freight

Rail and Truck Ton-Miles Continue to Rise

by Scott M. Dennis, Ph.D.

Domestic freight traffi c carried by air, 

truck, rail, water, and pipeline totaled more than 4.5 trillion ton-miles 

in 2005—an increase of more than 

350 billion over the 1996 total. This 

8.7 percent growth in ton-miles, the 

primary physical measure of freight 

transportation output, refl ects a 0.9 

percent compound annual growth 

rate between 1996 and 2005, the latest year for which complete data are 

available. However, the overall growth 

masks some notable differences 

among modes, with ton-miles in three 

modes (rail, truck, and air) increasing 

while ton-miles in the other two modes 

(pipeline and water) declined over the 

10-year span. Figure 1 illustrates the 

growth of domestic freight ton-miles 

during this time period.1

While there was mostly year-to-year 

growth in overall ton-miles during the 

decade, it is estimated that total domestic ton-miles declined from 4.542 

trillion in 2004 to 4.538 trillion in 2005, 

a decline of 0.1 percent. This preliminary estimate is essentially unchanged 

for 2005 relative to the previous year.

Modal Trends 

The two largest modes in terms of 

ton-miles, rail and truck, grew the 

fastest between 1996 and 2005—25.9 

percent for rail (a compound annual 

1

 Ton-miles do not refl ect revenues earned 

or the value of commodities transported.

growth rate of 2.6 percent) and 21.8 

percent for trucks (a compound annual growth rate of 2.2 percent). The 

growth of these two modes refl ects the 

continued growth of the goods sector 

of the economy generally. Air freight 

ton-miles, while a small fraction of 

railroad and truck ton-miles, also grew 

faster than domestic freight ton-miles 

as a whole—14.3 percent over the period (a compound annual growth rate 

of 1.5 percent). The growth pattern of 

air freight ton-miles over the period 

refl ects a dramatic decline in air traffi c 

after September 11, 2001 and its subsequent recovery. Figure 2 presents 

What is a ton-mile?

A ton-mile is defi ned as one ton of 

freight shipped one mile and, therefore, refl ects both the volume shipped 

(tons) and the distance shipped (miles). 

Ton-miles provide a key measure of the 

overall demand for freight transportation services, which in turn refl ects 

the overall level of industrial activity 

in the economy. In addition, ton-miles 

are used to calculate other measures 

of transportation system performance, 

such as energy effi ciency and accident, 

injury, and fatality rates.

Figure 1: Total U.S. Domestic Freight Ton-Miles

1996 1997 1998 1999 2000 2001 2002 2003 2004 2005

3,900

4,000

4,100

4,200

4,300

4,400

4,500

4,600 Ton-miles (billions)

SOURCE: U.S. Department of Transportation, Research and Innovative Technology Administration, Bureau 

of Transportation Statistics, calculations using data from various sources. See box at the end of this report for 

details.
BTS Special Report

the ton-mile data for each mode as an index, showing the 

change for each mode relative to its 1996 value.

Pipeline traffi c declined by 5.5 percent from 1996 to 2005 

(a compound annual growth rate of -0.6 percent). The 

decline in pipeline ton-miles largely refl ects the decline 

in domestic petroleum production. Waterborne ton-miles 

declined by 22.7 percent over the period (a compound 

annual growth rate of -2.8 percent). The decline in waterborne ton-miles is primarily due to declining coastwise 

shipments of Alaskan petroleum.

Market Share 

Figure 3 illustrates the market shares as measured by tonmiles for each of the modes in 1996 and 2005. Although 

the rank order for each mode did not change, nevertheless 

there were shifts in market shares among the fi ve modes. 

While the market shares in this fi gure illustrate the primary 

physical measure of freight transportation output, they do 

not refl ect the revenues earned or value of commodities 

transported by various modes.

The railroad mode includes large Class I railroads (2005 

operating revenue in excess of $319.3 million) as well as 

smaller local and regional railroads. Railroads carry the 

largest share of ton-miles, with a market share of 38.2 

percent in 2005, up from 33.0 percent in 1996. Trucking, 

which includes both local and intracity truck transportation, 

carries the next largest share at 28.5 percent–a more than 

3-percentage point increase from 1996. Pipelines, which 

include crude petroleum, petroleum products, and natural 

gas pipelines, account for 19.9 percent of domestic freight 

ton-miles—a 3.0 percent decline in market share over 

the 10-year span. Waterborne traffi c, which includes 

Figure 2: Index of U.S. Domestic Freight Ton-Miles (1996 = 100)

1996 1997 1998 1999 2000 2001 2002 2003 2004 2005

60

70

80

90

100

110

120

130

Air

Truck

Railroad

Water

Pipeline

Total

Index

SOURCE: U.S. Department of Transportation, Research and Innovative Technology Administration, Bureau of Transportation Statistics, calculations using data from various sources. See box at the end of this report for details.

Table 1: U.S. Domestic Freight Ton-Miles by Mode (ton-miles, billions)

1996 1997 1998 1999 2000 2001 2002 2003 2004 2005

Percent Change 

1996 - 2005

Air 13.8 13.9 14.1 14.5 15.8 13.3 13.8 15.1 16.5 15.7 14.3%

Truck 1,062.0 1,110.6 1,139.8 1,176.4 1,192.8 1,213.2 1,245.5 1,264.8 1,281.6 1,293.3 21.8%

Railroad 1,377.1 1,391.1 1,448.4 1,503.7 1,546.3 1,599.3 1,605.5 1,603.6 1,684.5 1,733.8 25.9%

Water 764.7 707.4 672.8 655.9 645.8 621.7 612.1 606.1 621.2 591.3 -22.7%

 Coastwise 408.1 349.8 314.9 292.7 283.9 274.6 263.7 278.9 279.9 263.5 -35.4%

 Lakewise 58.3 62.2 61.7 57.0 57.9 50.9 53.7 47.5 55.7 51.9 -11.0%

 Internal 296.8 294.0 294.9 304.7 302.6 294.9 293.4 278.4 284.1 274.4 -7.6%

 Intraport 1.5 1.4 1.4 1.4 1.5 1.4 1.3 1.3 1.5 1.5 3.1%

Pipeline 956.6 956.5 953.5 950.2 927.9 910.0 932.0 925.2 938.0 903.8 -5.5%

 Oil & Oil Products 619.2 616.5 619.8 618.0 577.0 576.0 586.0 590.0 599.6 572.0 -7.6%

 Natural Gas 337.4 340.0 333.7 332.2 350.9 334.0 346.0 335.2 338.4 331.8 -1.7%

TOTAL 4,174.1 4,179.4 4,228.6 4,300.6 4,328.6 4,357.5 4,409.0 4,414.8 4,541.7 4,537.9 8.7%

SOURCE: U.S. Department of Transportation, Research and Innovative Technology Administration, Bureau of Transportation Statistics, calculations using data 

from various sources. Numbers may not add to total due to rounding. See box at the end of this report for details.
BTS Special Report

Figure 3: U.S. Domestic Freight Market Share (percent of ton-miles in 1996 and 2005)

Air Truck Railroad Water Pipeline

0

5

10

15

20

25

30

35

40

1996 2005

0.3 0.3

25.4

28.5

33.0

38.2

18.3

13.0

22.9

19.9

Percent

SOURCE: U.S. Department of Transportation, Research and Innovative Technology Administration, Bureau of Transportation 

Statistics, calculations using data from various sources. See box at the end of this report for details.

coastal, Great Lakes, inland waterway, and local port 

traffi c, accounts for 13.0 percent of domestic freight tonmiles—compared to 18.3 percent in 1996. Air freight, 

which includes freight carried by passenger operators as 

well as all-cargo operators, accounts for 0.3 percent of 

domestic freight ton-miles. 

Estimation of Ton-Miles

Several different national estimates of ton-miles have been 

developed by various organizations over the years. These 

estimates have differed in coverage and reliability. The 

Bureau of Transportation Statistics (BTS) is working to 

improve basic measures of transportation activity, including 

ton-miles. In this report BTS estimates for air, truck, rail, 

water, and pipelines were developed using a more comprehensive approach than was used in prior estimates. 

Fuller coverage is achieved by combining reported data 

from established sources, estimates from surveys, and 

calculations based on certain assumptions. For more information on the improved approach, including discussion of 

data sources and methods used, visit the BTS web site at 

www.bts.gov, and use the search engine to fi nd improved 

estimates of ton-miles.

BTS has used the improved methodology to estimate tonmiles from 1980 onwards. The fi gures on the next page 

show the change in ton-miles for this period. Data points 

for each year from 1980 to 2005 are found in National 

Transportation Statistics, an online publication also on the 

BTS website, at table 1-46(b).

For related data and publications visit www.bts.gov

This article was prepared by Scott M. Dennis, Economist, of the Bureau of Transportation Statistics (BTS). BTS is a component of DOT’s 

Research and Innovative Technology Administration (RITA). 

The estimates in this report were developed from a variety of data 

sources. The principal data sources for each mode are:

 Air: USDOT, RITA, BTS, Air Carrier Traffi c Statistics Monthly 

 Truck: USDOT, RITA, BTS, 2002 Commodity Flow Survey

 Rail: Surface Transportation Board, Carload Waybill Sample

 Water: U. S. Army Corps of Engineers, Waterborne Commerce of 

 the United States

 Pipeline: Association of Oil Pipelines, Shifts in Petroleum Transpo-

 rtation; U. S. Department of Energy, Energy Information Admin-

 istration, Annual Energy Review

For questions about this or other BTS reports, call 

1-800-853-1351, email answers@bts.gov, or visit 

www.bts.gov.

Data — 

Commodity Flow Survey—survey reporting value, weight, and 

ton-miles by commodity, mode, origin, and destination.

National Transportation Statistics—ton-mile data from 1980 

to present.

Publications — 

Journal of Transportation Statistics, Vol. 8, No. 1, Improved 

Estimates of Ton-Miles

Freight in America, A New National Picture 2006

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About this Report
BTS Special Report

1980

1985

199019952000

2005

0

0.5

1

1.5

2

Truck ton-miles (trillions) Railroad ton-miles (trillions)

0

0.5

1

1.5

2

1980

1985

199019952000

2005

Water ton-miles (trillions)

0

0.5

1

1.5

2

1980

1985

199019952000

2005

Pipeline ton-miles (trillions)

0

0.5

1

1.5

2

1980

1985

199019952000

2005

Air ton-miles (billions)

0

5

10

15

20

1980

1985

1990

19952000

2005

Figure 4: BTS Ton-mile Calculations, by Mode

SOURCE: U.S. Department of Transportation, Research and Innovative Technology Administration, Bureau of Transportation Statistics, calculations using 

data from various sources. See box on previous page for details.

NOTE: The fi gure for air ton-miles (blue) is in 

billions; the fi gures for truck, rail, water, and 

pipeline are in trillions.