Transportation Economic Trends

Transportation Productivity:

Revenue per Unit of Output

The impact of productivity can be seen through the price charged per unit of output. This page discusses two units of output: (1) freight revenue per ton-mile and (2) passenger revenue per passenger-mile. For modes where users do not typically pay per use, like driving a personal vehicle, data are difficult to obtain and not presented here.
2020 and 2021 Year-in-Review
2021 data is only available for some modes.
  • Domestic air carriers' freight revenue per ton-mile fell for the second consecutive year in 2021. The decline indicates a potential reduction in air freight transportation costs. 
  • Truck and oil pipeline revenue per ton-mile increased from 2019 to 2020 by 0.2 percent and 1.0 percent, respectively. The increase contrasts with a decline in the Producer Price Index (PPI), meaning shippers likely faced higher truck and oil pipeline transportation costs in 2020 but lower prices for all other goods and services.
  • Rail, water, and air transportation revenue per ton-mile contrastingly declined from 2019 to 2020 by 0.3 percent, 8.5 percent, and 10.7 percent, respectively. The decline in rail revenue per ton-mile was less than the decline in the overall price for goods and services (as measured by the PPI), while the decline in water and air revenue per ton-mile exceed the decline in the PPI. This suggests that shippers faced lower rail, water, and truck transportation prices in 2020, but shippers purchasing rail transportation services benefited less from the overall decline in prices than shippers purchasing water and air transportation services.
  • In 2021, intercity rail/Amtrak passenger and commuter rail revenue per passenger mile fell by 15.3 percent and 8.6 percent, respectively, suggesting a potential decline in the prices travelers faced for these services. Air passenger revenue per passenger mile grew in 2021 but more slowly, 2.3 percent, than the Consumer Price Index (CPI), which means travelers likely faced higher airfares in 2021 but less than expected from the overall price increase in goods and services (as measured by the CPI).

Revenue Per Unit of Output
Productivity increases often reduce businesses' costs, which allows transportation companies to offer lower prices, which, assuming no change in the amount of transportation services purchased by users, translates into lower average revenue per passenger and ton-mile.
Freight Revenue Per Ton-Mile
For for-hire freight transportation, the unit of output is ton-miles, and the measure of what freight shippers pay is the average freight revenue per ton-mileComparing average freight revenue per ton-mile to the PPI shows whether it rose more or less than expected due to inflation. The PPI measures overall changes in the selling prices received by transportation service providers for their services and is a measure of inflation but from the producer's perspective.
If revenue per mile trends similarly to the PPI, an increase in revenue per ton-mile can be attributed to rising prices. An increase greater than the increase in the PPI suggests an increase in freight transportation costs passed on to purchasers in the form of higher prices. Conversely, an increase less than the PPI suggests a decline in costs passed on to purchasers in the form of lower prices. 
Passenger Revenue Per Passenger-Mile
For for-hire passenger transportation, the unit of output is passenger-miles, and the measure of what travelers pay is the average passenger revenue per passenger-mile. Comparing average passenger revenue per passenger-mile to the CPI shows whether it rose more or less than expected due to inflation. The CPI measures overall changes in prices paid by households.
If revenue per mile trends similarly to the CPI, an increase in passenger revenue per passenger-mile can be attributed to rising prices. An increase greater than the CPI suggests an increase in passenger transportation costs passed onto consumers in the form of higher passenger transportation fares. Conversely, when revenue per passenger-mile increases less than the CPI, this suggests greater efficiency allowed transportation companies to offer lower fares.


Recommended citation
U.S. Department of Transportation, Bureau of Transportation Statistics, Transportation Economic Trends, available at

Bureau of Transportation Statistics
The Bureau of Transportation Statistics, part of the U.S. Department of Transportation, is the preeminent source of statistics on commercial aviation, multimodal freight activity, and transportation economics, and provides context to decision makers and the public for understanding statistics on transportation.