South Dakota Department of Transportation’s $8.4 million U.S. Highway 16/Hell Canyon Reconstruction project improved safety conditions and was completed 10 months ahead of schedule. The new roadway adds additional space on the road while reducing the number of dangerous curves along the highway. SDDOT and partners also worked to prevent construction-related environmental damage to nearby Jewel Cave, a major landmark in the area and third longest cave in the world. The updated road improves safety for visitors and motorists without negatively impacting the environment.