The American Trucking Associations' advance seasonally adjusted (SA) For-Hire Truck Tonnage Index decreased 1.4 percent in June, although May's reduction was revised from 0.6 percent to just 0.1 percent. 'May and June marked the first back-to-back contractions since March and April 2009. The latest reduction lowered the SA index from 110.1 (2000=100) in May to 108.5 in June.

The not seasonally adjusted index, which represents the change in tonnage actually hauled by the fleets before any seasonal adjustment, equaled 115.9 in June, up 6.5 percent from the previous month.

Compared with June 2009, SA tonnage climbed 7.6 percent, which was just below May's 7.7 percent increase and the seventh consecutive year-over-year gain. Year-to-date, tonnage is up 6.6 percent compared with the same period in 2009.

ATA Chief Economist Bob Costello said that the two sequential decreases reflect an economy that is slowing.' Furthermore, growth in truck tonnage is likely to moderate in the months ahead as the economy decelerates and year-over-year comparisons become more difficult.' Nevertheless, Costello believes that tonnage doesn't have to grow very quickly at this point since industry capacity has declined so much.' 'Due to supply tightness in the market, any tonnage growth feels significantly better for fleets than one might expect.'

Note on the impact of trucking company failures on the index: Each month, ATA asks its membership the amount of tonnage each carrier hauled, including all types of freight.' The indexes are calculated based on those responses.' The sample includes an array of trucking companies, ranging from small fleets to multi-billion dollar carriers. When a company in the sample fails, we include its final month of operation and zero it out for the following month, with the assumption that the remaining carriers pick up that freight.' As a result, it is close to a net wash and does not end up in a false increase.' Nevertheless, some carriers are picking up freight from failures, and it may have boosted the index. Due to our correction mentioned above, however, it should be limited.

Trucking serves as a barometer of the U.S. economy, representing 68 percent of tonnage carried by all modes of domestic freight transportation, including manufactured and retail goods.

Trucks hauled 8.8 billion tons of freight in 2009. 'Motor carriers collected $544.4 billion, or 81.9 percent 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.