The Transportation Services Index (TSI) rose to 112.6 in May 2005,1 the highest level attained in the 15-year period beginning January 1990, and a 4.0 percent increase from its May 2004 level of 108.3 (figure 9-1). 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 .
The Bureau of Transportation Statistics (BTS), which produces the measure, calculates the TSI as a single transportation index and as separate indexes for its two components-freight and passenger transportation. The freight TSI rose to 113.1 in May 2005, 2.4 percent higher than May 2004 (110.5), and reached a record high for the 15-year period covered by the index. In May 2005, the passenger TSI was 111.2, an increase of 8.2 percent from 102.8 in May 2004.
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. A prototype version of the TSI suggested a significant relationship with the economy, in particular, with cyclical downturns. To verify these linkages, however, more research is needed.
1. U.S. Department of Transportation, Research and Innovative Technology Administration, Bureau of Transportation Statistics, Transportation Services Index, available at http://www.bts.gov/, as of August 2005.
1 The TSI is a chained-type index where 2000 = 100.