Development projects in downtown Cedar Rapids and parts of Coralville and Iowa City will be eligible for a new federal tax incentive.The U.S. Department of the Treasury has designated seven parts of the three cities as Opportunity Zones, according to a list from the department. The federal program, slipped into last year’s tax law, is intended to incentivize development in low-income Census tracts by giving investors a break on capital gains taxes.The Treasury Department designated three zones in Cedar Rapids that include much of the city’s core — including downtown, the MedQuarter, the New Bohemia District and Kingston Village.Coralville has two zones that include Iowa River Landing, Coral Ridge Mall and a 17-acre site in between Clear Creek and First Avenue.