Uncertainty about the presidential election is slowing large construction projects, according to the American Institute of Architects, whose monthly index of billings remained in positive territory last month, although it dropped slightly. The index is an indicator of construction spending nine months to a year in the future. The reading for July was 51.5, down from 52.6 in June. Any reading above 50 indicates an increase in billing activity. The new projects inquiry index was 57.5, down from a reading of 58.6 the previous month. “The presidential election that lies ahead is definitely impacting the progression of larger construction projects and funding decisions,” AIA Iowa Executive Director Jessica Reinert said in a release. “The ABI still reflects an increase in billings but we expect higher levels of volatility in the design and construction sector once the political scene settles.”