The Associated Builders and Contractors’ (ABC) Construction Backlog Indicator (CBI) expanded by one percent to 8.5 months during the second quarter of 2015. Backlog declined 3 percent during the first quarter, which was punctuated by harsh winter weather and the lingering effects of the West Coast ports slowdown, according to the ABC report. CBI stands roughly where it did a year ago, indicative of an ongoing recovery in the nation’s nonresidential construction industry.

“The nation’s nonresidential construction industry is now one of America’s leading engines of growth,” says ABC chief economist Anirban Basu. “The broader U.S. economic recovery is now in its 74th month, but remains under-diversified, led primarily by a combination of consumer spending growth as well as residential and nonresidential construction recovery.”

“Though CBI expanded during the second quarter, performance continues to be uneven,”  adds Basu.  “A surge in heavy-industrial investment in the Middle States, including in the auto sector, and technology-led growth in the West were responsible for the bulk of second-quarter momentum. Backlog actually slipped in the infrastructure category, which remains hamstrung by uncertainties lingering around the Highway Trust Fund. Backlog was not statistically significantly different in the South between the first and second quarters.”

The West experienced a significant expansion in backlog, rising 1.2 months following the resolution of the West Coast port slowdown, while backlog in the region remains nearly 2.5 months below its year-ago levels, the largest drop of any region.

Backlog in the South has essentially returned to where it was two years ago, in part because of a slowdown in energy-related investment, according to the report. Backlog slipped for a second consecutive quarter in the Northeast, but remains above levels registered during the second half of 2013.

Commercial/institutional backlog has remained above eight months on average for 12 consecutive quarters. Backlog for all industry segments is higher on a year-over-year basis with the exception of the commercial/institutional segment.