Construction spending declined 1.8% in July, the biggest downturn in more than three years, the Commerce Department reported Aug. 1.
The decline followed a revised 0.8% gain in May that was higher than an originally reported 0.1% increase.
The decline was the biggest since a 2.8% drop in January 2011.
Private construction spending fell 1%, with private residential construction down 0.3% and private nonresidential construction dropping 1.6%.
Public construction fell 4%, the biggest decline since March 2002. Federal construction rose 10.4%, but state and local construction declined 5.2%.
Construction spending can boost demand for trucking services because spending increases the number of shipments of goods and building materials.