North Carolina's sprawling upgrade of the Interstate 85/485 interchange near Charlotte, N.C., is proving that a bigger design can actually deliver significant cost savings.
Part of the North Carolina Dept. of Transportation's (NCDOT) program to fill the last six-mile gap in the 65-mile I-485 outer loop around Charlotte, the interchange uses a two-level "turbine" configuration rarely found in the U.S. Also called a "whirlpool" interchange, the design features swirling lanes that take left-turning traffic around a central bridge in a clockwise direction.