WASHINGTON, DC-The Architecture Billings Index rose to its highest level since late 2010, crossing—finally—the all-important 50 benchmark. The September ABI score was 51.6, up from 50.2 in August.

On one hand, the score is reason for optimism for the industry—a leading indicator for construction, it reflects an increase in demand for design services and anything above 50 indicates an increase in billings. On the other hand, it has crossed the 50 mark threshold before since the crash—and then retreated. For that reason it is difficult to say whether now, finally, is the time to get enthusiastic about the industry's near term prospects, AIA chief economist Kermit Baker tells GlobeSt.com.

"We've had so many false starts." That said, he is feeling hopeful this go around because of the recent momentum in the residential sector. "That is unlikely to be reversed, which makes me feel positive about non-residential activity." On the other hand, he said, the uncertainty in the economy and political situation is a big concern. "We have to wait and see how Congress deals with the fiscal issues, he says. "So, I don’t think it is time to say 'happy days are here again.'"

AIA also reported that the new projects inquiry index was 57.3, compared to a mark of 57.2 the previous month. Broken down by region, the ABI posted a 53.4 for the West; 51.9 for the South; 49.5 for the Northeast; and 47.2 for the Midwest. By sector, multi-family residential posted a score of 57.3; institutional, 51; commercial / industrial, 48.4; mixed practice, 47.8.