Truck tonnage was also down compared to the preceding two months, according to the American Trucking Associations. The organization's seasonally adjusted for-hire truck tonnage index fell 0.3% from August. By contrast, the August index showed a 2.1% increase from the July level. The September index registered 103.9, with the year 2000 as the base year at 100.

The decline in the reading indicates economic recovery will be "moderate and choppy," in the words of ATA chief economist Bob Costello, but he says the industry should not be alarmed by the decrease."We took two steps forward in July and August, and this was a miniscule step backward," he remarks. While he says the industry should be prepared for ups and downs in coming months, he believes the general trend runs toward moderate improvement.

According to the Association of American Railroads, US rail intermodal traffic fell to 993,235 units in September compared to 1.16 million carloads in August and 1.38 million carloads in September '08. However, the association says heavy flooding in the Southeast kept the numbers lower than might otherwise have been the case. A decline in demand for coal due to more moderate summer temperatures also contributed, it adds.