Construction employers added 29,000 jobs in February 2015 and 321,000 over the past year, reaching the highest employment total in six years, as the sector's unemployment rate fell to an eight-year low of 10.6%, according to the Associated General Contractors of America. Association officials cautioned, however, that construction jobs in the highway and transit sector were at risk because of Washington gridlock.

"Despite challenging weather conditions in much of the country, both the number of workers and their average weekly hours rose last month to the highest levels since the recession," said Ken Simonson, the association's chief economist. "There are lots of good-paying, full-time jobs available in construction, with more work on the way."

Construction employment totaled more than 6.3 million in February, the highest mark since February 2009, with a 12-month gain of 321,000 jobs or 5.3%, Simonson noted. Average weekly hours of all employees climbed to 39.6 hours and weekly earnings averaged $1,066 in construction, the highest levels in the nine-year history of both series. Weekly earnings in construction were 24% above the private-sector average.

Residential building and specialty trade contractors added a combined 16,700 employees since January and 167,800 (7.4%) over 12 months. Nonresidential contractors — building, specialty trade, and heavy and civil engineering construction firms — hired a net of 12,000 workers for the month and 153,400 (4.1%) since February 2014.

The number of workers who said they looked for work in the past month and had last worked in construction fell from 1,098,000 a year earlier to 906,000 — the lowest February mark in nine years. Although winter conditions typically result in a high February unemployment rate for construction, the 10.6% unemployment rate for these workers was the lowest February rate since February 2007 and represented a steep drop from a year earlier, when the rate was 12.8%, Simonson noted.

"Contractors in most states appear optimistic about the prospects for construction, especially for apartments and private nonresidential projects," Simonson added. "In contrast, the highway funding outlook is murky."

Association officials said that employment in highway and transit construction was at risk if Congress and the Obama administration fail to find a way to pay for, and enact, a long-term federal highway and transit bill. They said that even as many states take measures to cope with declining federal transportation funding, if Washington can't pass a bill by May 31 when current legislation expires, some firms may have to reduce staff.

"The highway and transit funding shortfall is one of those classic Washington-created problems that could easily be fixed," said Stephen E. Sandherr, the association's chief executive officer. "For just a few dollars more per year, Washington could save commuters and other road users thousands of dollars by cutting commuting times and improving road conditions."