ARLINGTON, VA. — The American Trucking Associations’ (ATA) advanced seasonally adjusted (SA) For-Hire Truck Tonnage Index decreased by 3.8 percent in October after falling 0.4 percent in September.

The ATA said October’s result was the third consecutive drop totalling 4.7 percent, the lowest level since May 2011. Compared with October 2011, the SA index was off by 2.1 percent, the first year-over-year decrease since November 2009.

Year-to-date, compared with the same period last year, tonnage was up 2.9 percent.

The not seasonally adjusted index was 7.7 percent above the previous month.

“Clearly Hurricane Sandy negatively impacted October’s tonnage reading,” said Bob Costello, ATA chief economist. “However, it’s impossible for us to determine the exact impact.”

Costello also noted that a large drop in fuel shipments into the affected area likely put downward pressure on October’s tonnage level since fuel is heavy freight, in addition to reductions in other freight.

“I’d expect some positive impact on truck tonnage as the rebuilding starts in the areas impacted by Sandy, although that boost may only be modest in November and December,” Costello said. “Excluding the Hurricane impacts, I still think truck tonnage is decelerating along with factory output and consumer spending on tangible-goods.”