ARLINGTON, VA.— The American Trucking Associations’ advanced seasonally adjusted (SA) For-Hire Truck Tonnage Index for July fell 0.4 percent. That’s the first drop since April and comes as no surprise, said ATA Chief Economist Bob Costello.

“After gaining a total of 2.2 percent in May and June, it isn’t surprising that tonnage slipped a little in July,” Costello said. “The decrease corresponds with the small decline in manufacturing output during July reported by the Federal Reserve last week.”

Compared with July 2012, the SA index was 4.7 percent higher. That’s robust, ATA said, but also the smallest year-over-year gain since April.

“Despite the small reprieve in July, we expect solid tonnage numbers during the second half of the year as sectors that generate heavy freight, like oil and gas and autos, continue with robust growth,” Costello explained.

“Home construction generates a significant amount of tonnage, but as mortgage rates and home prices rise, growth in housing starts will decelerate slightly in the second half of the year, but still be a positive for truck freight volumes. Tonnage gains in the second half of the year are likely to overstate the strength in the economy as these heavy freight sectors continue to outperform the economy overall.”

For more on July’s tonnage report, check out Costello’s explanation below: