SPR US Highway 16 Corridor Study I-229 Exit 3 (Minnesota Avenue) and Exit 4 (Cliff Avenue) Interchange & Environmental Study I-229 Exit 6 (10th Street) Interchange Study SD44 - Platte/Winner Bridge Corridor Study I-90 Exit 46 (Elk Creek Road) Interchange Modification Study I-90 Exit 63 (Box Elder/Ellsworth AFB Commercial Gate) Interchange Study U.S. 385 Roadway Improvement Study SD 100 Corridor Preservation Project US14A/US85/Deadwood Box Corridor Study South Veterans Parkway (Highway 100) US Highway 212/Forest City Bridge Corridor Study Union County Master Transportation Plan Study Tabor to Platte Rail to Trail Feasibility Study Ethan Master Transportation Plan Study Dimock Master Transportation Plan Study