Business inventories rose 0.5% in August, the Commerce Department said Friday.
The increase followed a revised 0.5% gain in July that was bigger than the 0.4% originally reported.
August inventories, which rose as businesses anticipated faster sales growth, were projected to increase 0.4%, Bloomberg reported.
Auto and parts stockpiles rose 1.5%, the biggest gain in a year.
When sales are growing, it usually means trucking is seeing additional demand to deliver goods and restock shelves.