Well there is precidence. the original Sunshine State Parkway went from North Miami to Ft. Pierce and was financed by bonds. When the bonds were paid off, they had a ceremony, the SSP was toll-free for one day, the name changed to Florida's Turnpike, the Ft. Pierce to Wildwood extension announced, and the tolls were reinstated.
Incidently when you look at I-95 just south of Ft. Pierce, it make this strange loop of about 10 miles into the hinterlands, then returns to the coast south of Stuart. There are two schools of thought. The first is that some politician's buddy had land out west that he wanted the Interstate to run through. The second was to make sure that the toll SSP was significantly shorter from Ft. Piece to the Gold Coast than the free Interstate.