The amount of freight carried by the for-hire transportation industry rose 0.9% in September from August, reaching the highest level since July 2008, according to the U.S. Department of Transportation's Bureau of Transportation Statistics.

BTS reported that the level of freight shipments, measured by the Freight TSI, rose 4.2% in the last four months to reach the new level.

The Freight TSI measures the month-to-month changes in freight shipments by mode of transportation 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.

Shipments in September 2011 (109.6 on the index) were at the highest level since July 2008 (109.9). July 2008 was followed by six straight months of decline. After dipping to a recent low in April 2009 (94.3), freight shipments increased in 20 of the last 28 months.

For the first nine months of 2011, freight shipments measured by the index were up 2.5%.

Freight shipments in September 2011 (109.6 on the index) rose 16.2% from the recent low in April 2009 (94.3), when freight shipments were at their lowest level since June 1997 (92.3). The September 2011 level is down 3.3% from the historic freight shipment peak reached in January 2005 (113.3).

Long-term, freight shipments are down 1.4% in the five years from September 2006, but are up 11.8% in the 10 years from September 2001, despite declines in recent years.

The TSI is a seasonally adjusted index that measures changes from the monthly average of the base year of 2000.