The truck tonnage index has fallen three consecutive months, dropping a total of 1.5 percent according to new figures released by the American Trucking Association on Tuesday, Sept. 27.

According to an ATA press release, on a seasonally adjusted basis, the tonnage index fell from 114.4 to 113.5 in July.

Year-to-date, the truck tonnage index was up 2.2 percent, compared to the same time period in 2004. The tonnage index in August 2005 was 0.7 percent higher than a year earlier. On a not-seasonally adjusted basis, the tonnage index jumped 10.8 percent from July to a record high 123.1.

ATA calculates the tonnage index based on surveys from its membership and has been doing so since the 1970s. According to the release, these are preliminary figures and are subject to change in the final report issued around the tenth day of the month.