The ramp of Exit 4 of I-295 in South Portland will be temporarily closed from Aug. 9 through Aug. 11 as part of the ongoing construction project to add a new, two-way overpass to the highway. The new overpass is expected to be completed this fall, about a year and half after construction began. The $12.4 million project will make the overpass a two-way road, adding southbound access to I-295 from Main Street in an effort to ease traffic on Broadway — the main, cross-town artery. There is currently no southbound access from that interchange to I-295, and many drivers normally access the highway through Exit 3. The project will also include a new off-ramp from Veterans Memorial Bridge to I-295 to allow southbound access.