Transportation Services Index inched up in December

The Transportation Services Index (TSI) increased a tad in December, rising 0.1 percent from November's level to 122.6, according to the U.S. Department of Transportation's Bureau of Transportation Statistics (BTS). On a year-over-year basis, the index rose 3.3 percent.

The Freight TSI of 123.8 was virtually unchanged from November's mark of 123.9, ending a string of five straight month-over-month gains.

"Trucking, rail carloads and waterborne [traffic] grew in December, but air freight, pipeline and rail intermodal decreased, resulting in the overall freight index remaining almost level," BTS officials said in a press release. "While the economy as measured by income and employment grew in December, it is notable that inventories, closely tied to freight transportation, declined in December for the first time in 19 months."

A measure of output from rail, trucking, inland waterway, pipeline and air freight service providers, the Freight TSI increased 4.2 percent compared with December 2013's index.

December's Passenger TSI increased 0.4 percent from November's level to 122.6. The measure of month-to-month changes in travel services provided by air, local transit and intercity rail companies grew 1.3 percent compared with December 2013's index.

In the fourth quarter, the TSI increased 1.1 percent, Freight TSI rose 1.7 percent and Passenger TSI declined 0.1 percent compared with third-quarter 2014 figures.