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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.

 

 

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