It takes millions of giant green placards to make America navigable. Where do they come from — and who pays the bill? Zachary Crockett takes the exit.
- SOURCES:
- Lee Blackman, general manager at Correction Enterprises.
- Gene Hawkins, senior principal engineer at Kittelson and professor emeritus of civil engineering at Texas A&M University.
- Renee Roach, state signing and delineation engineer for the North Carolina Department of Transportation.