The Transportation Services Index is climbing slowly but has not returned to the rapid growth seen before the recession, according to the Bureau of Transportation Statistics, which released a technical note on freight transportation services Dec. 15.
Created by the U.S. Department of Transportation, the TSI measures the movement of freight and passengers. BTS produces three indexes — one for freight, one for passengers and one that combines the two. The freight index is a weighted average of data for trucking, freight rail, waterborne, pipeline and air freight.
The agency reported that the Great Recession, which spanned from December 2007 to June 2009, distinguished two periods of growth in freight transportation services. The Freight Transportation Services Index grew 2.28 index points above the long-term trend from November 2004 to January 2008, but grew only .85 points after the recession through 2016.
“The truck and rail modes, which are the largest components of [Freight TSI], show similar patterns, though the pattern is more dramatic for rail than for truck,” BTS stated. “The [Freight TSI] growth rate has been above the long-term trend following the recession but has not returned to the fast-paced growth prior to the recession.”
This trend contrasts with Gross Domestic Product, which saw post-recession growth that matched pre-recession growth. According to BTS, the pace of GDP growth of 2.1% after the recession through 2016 matches its rate of 2% before the recession.
Prior to the recession, TSI experienced extended growth periods that outpaced the long-term trend in freight transportation services, according to BTS. The agency found that rail ton miles and truck tonnage have not regained their previous growth rate, and that this failure to reach the pace of pre-recession growth is more dramatic for rail traffic than it is for truck tonnage.
In order to determine Freight TSI, the bureau removes seasonal variation in activity, such as the freight ramp-up preceding the holidays. The seasonally adjusted data is then de-trended to remove the long-term trend in the data and to show short-term trends. The de-trended data is then smoothed to remove factors that can obscure short-term trends and turning points, such as unseasonable weather and spikes in the movement of particular commodities.
“The [Freight TSI] began to rise quickly after turning in May 2009, one month ahead of the economic acceleration following the recession, but has since slowed,” the BTS report states. “Growth in the last few years since the recession has fallen short of pre-recession growth, as shown by the de-trended and smoothed values of the [Freight TSI]. The de-trended and smoothed values have risen only slightly above zero since the recession.”