NOTE: Previous releases with Chain-type Index 1996 = 100 are still available.
The Transportation Services Index (TSI), created by the U.S. Department of Transportation (DOT), Bureau of Transportation Statistics (BTS), measures the movement of freight and passengers. The index, which is seasonally adjusted, combines available data on freight traffic, as well as passenger travel, that have been weighted to yield a monthly measure of transportation services output.
Monthly data changes with each release due to the use of concurrent seasonal analysis, which results in seasonal analysis factors changing as each month's data are added.
TSI numbers are BTS estimates.