Transportation Services Index

Transportation Services Index

The Transportation Services Index (TSI), a new product of the Bureau of Transportation Statistics (BTS), rose to 122.51 in March 2004, its highest level since January 1990 and a growth of 1.0 percent since the previous month (figure 13-1). The TSI is an experimental, seasonally adjusted index of monthly changes in the output of services of the for-hire transportation industries, including railroad, air, truck, inland waterways, pipeline, and local transit. BTS calculates the TSI as a single transportation index and as separate freight and passenger indexes.

As of March 2004, the TSI had risen every month since August 2003 except for a drop in January 2004 to 119.3. The freight TSI rose to 123.3 in March 2004, 6.0 percent higher than in March 2003, and a record high for the 14-year period covered by the index. However, the passenger TSI decreased 0.1 percent in March 2004 (to 120.5) after two consecutive rises in January and February of 2004 [1].

BTS released the first TSI data (covering January 1990 through December 2003) in March 2004. The index is still under development as BTS works to refine the index data sources, methodologies, and interpretations. Both the TSI and the freight index show potential to be considered leading indicators of economic performance. A prototype version of the TSI was successful at forecasting downturns in the economy and slightly less accurate in projecting upturns. To verify these linkages, however, more research is needed.

Economists, forecasters, and others use monthly economic measures to understand the performance of the economy, to understand the short-term relationships among different sectors of the economy, and to forecast the performance of the economy, particularly business cycles. To do this they use measures called “indicators,” such as employment, manufacturing production, sales, business inventories, purchasing managers’ plans, and consumer confidence. In addition to giving information that is valuable in its own right, these indicators often have a relationship with the growth of the economy, measured by the Gross Domestic Product.


1. U.S. Department of Transportation, Bureau of Transportation Statistics, Transportation Services Index, available at, as of June 2004.

1 The TSI is a chained-type index where 1996 = 100.