Transportation Department will begin releasing in March a monthly indicator of transportation services that Secretary Norman Mineta said will fill a gap in the broad measurement of the shape of the U.S. economy.
The Transportation Services Index (TSI) will represent the transportation sector’s 11 percent contribution to the gross domestic product. “Despite their economic importance, transportation services aren't traditionally well represented in statistics," Mineta said.
The TSI will use monthly data on freight movement and passenger travel in the for-hire transportation sector. Analysts from the Department’s Bureau of Transportation Statistics (BTS) will weigh and seasonally adjust the data to allow monthly and year-to-year comparisons.
The freight measures in the TSI will include for-hire trucking & parcel services, freight railroad services, inland waterway traffic, pipeline movements and air freight. The passenger transportation measures will be local transit, intercity passenger rail and air passenger transportation.
Jack Wells, chief economist at the Bureau of Transportation Statistics, said that freight numbers often serve as a leading indicator of activity in the overall economy. Goods transported by trucks, railroads, airplanes and pipelines are associated with buildups in inventories and other investments that tend to lead the economy, he said. One problem, he added, is the lag time between the time period covered by the index and when the statistics are released to the public.
The first index to be released next month will contain December data. Wells hopes that the lag time will decrease as BTS gains more experience in collecting, analyzing and disseminating the figures.