According to the 2000 Inter-Regional Corridor Study:
Inter-Regional Corridors tie the state together. They support Minnesota's economic health by connecting people with jobs, distributors with manufactures, shoppers with retailers, and tourists with recreational opportunities.
Inter-Regional Corridors (IRC) are portrayed as red and green lines on the map. Regional Corridors (RC) are portrayed as blue lines; they may be principal arterials (PA) or minor arterials (MA). Trunk highways are in grey.