The Freight Transportation Services Index fell 0.6 percent in August from its July level, falling after two monthly increases, according to the U.S. Department of Transportation's Bureau of Transportation Statistics.

The Freight TSI has risen 4.4 percent over the last 15 months, starting in June 2009, after declining 15.3 percent in the previous 10 months beginning in August 2008. The index has increased in 12 of the last 15 months. Through the first eight months of 2010, however, the index declined 1.9 percent.

The Freight TSI measures the month-to-month changes in freight shipments in ton-miles, which are then combined into one index. The index measures the output of the for-hire freight transportation industry and consists of data from for-hire trucking, rail, inland waterways, pipelines and air freight.

The August Freight TSI of 97.6 is a 4.4 percent increase from the recent low of 93.5 reached in May 2009. In May 2009, the index was at its lowest level since June 1997. The August Freight TSI is down 13.5 percent from its historic peak of 112.9 reached in May 2006.

Although the index rose 1.2 percent from August 2009 to August 2010, it remains below the level of every other August since 1997 when it was 94.8. January 2010 was the first month since July 2008 in which the Freight TSI exceeded the level of the same month of the previous year. The index has exceeded the previous year's level every month since January but still remains below the level of recent earlier years.

The freight index is down 12.7 percent in the five years from August 2005. The index is down 3.1 percent in the 10 years from August 2000.

The TSI is a seasonally adjusted index that measures changes from the monthly average of the base year of 2000. It includes historic data from 1990 to the present.