By using tax-exempt commercial paper, the North Texas Tollway Authority was able to lower interest rates in the early years of construction on projects such as the President George Bush Turnpike and increase debt capacity.  Commercial paper eliminates the need for capitalized interest and eliminates the potential for negative “costs of carry” in the construction fund.  In comparison to the traditional fixed-rate bond program the commercial paper program was projected to save approximately $43 million on $500 million in financing new projects.