The Iowa Transportation Commission has approved the final design plans for a new interchange for Interstate 29 at the Sioux Gateway Airport in Sioux City. D-O-T District Engineer Richard Michaelis says the approval allows them to begin taking bids for earthmoving portion of the project.That work could begin in the summer of 2002, and then they’d let bids on the bridges in the fall for construction in the winter of 2002. The paving would begin in the spring of 2003. Michaelis says the nearly 12-million dollar project will include temporary loop ramps to allow access to Sergeant Bluff and the airport from the north.Sioux City Mayor Marty Dougherty says the design of the bridges will feature the prairie-style architecture of local buildings, such as the Woodbury County Courthouse. It’s part of a new design philosophy in building bridges.The new interchange will also extend the overpass beyond railroad tracks, eliminating an at-grade crossing.