ALEXANDRIA, Va. The American Trucking Associations advanced seasonally adjusted For-Hire Truck Tonnage Index decreased 2.2% in April, after posting a 1.2% jump in March.

On a seasonally adjusted basis, the tonnage index declined to 112.1 in April from 114.6 the previous month. After Marchs year-over-year increase, which was the first since June 2006, Aprils tonnage was 2.7% below the same month in 2006.

The not seasonally adjusted index contracted 5.7% from March to 110.4.

ATA chief economist Bob Costello said the year-over-year decrease was not surprising, given the weak anecdotal reports from carriers as well as the unexpected strength in March.

Aprils tonnage figures highlight that the economy hasnt turned the corner just yet, he noted. We can expect this volatility to continue over the next few months, with the potential for more year-over-year contractions.

Costello said he anticipates that the industry will see a gradual improvement in volumes as the year progresses due to an inventory correction and a better economic outlook for 2008. These should combine to boost truck volumes.

Trucks hauled 10.7 billion tonnes of freight in 2005. Motor carriers collected $623 billion, or 84.3% of total revenue earned by all transport modes.

ATA calculates the tonnage index based on surveys from its membership and has been doing so since the 1970s. This is a preliminary figure and subject to change in the final report issued around the 10th day of the month.

The report includes month-to-month and year-over-year results, relevant economic comparisons, and key financial indicators.