Definition
The Triborough surplus was the recurring cash margin generated by the Triborough Bridge and Tunnel Authority's toll revenue after debt service and operating costs were paid. Tens of millions of dollars accumulated each year, controlled entirely by Robert Moses, restricted only by the loose statutory purposes of the authority, and committed to no elected official's program.
It was the single most consequential pool of discretionary money in New York for three decades, and its existence is the financial reason Moses could ignore mayors, governors, and the city council in turn. As long as the surplus was his, he was the buyer of construction services, not a beggar.
Why it matters
How it works
A toll authority designed to refinance its construction debt forever — because the bond covenants prevent early redemption — will, in normal conditions, generate revenue in excess of debt service every year. The excess is the surplus. Statutes typically constrain its uses to authority-related purposes, but those purposes can be defined generously, and the surplus can be lent, granted, or spent on adjacent projects.
For an administrator who controls the surplus, the power dynamic is inverted. The mayor cannot cut his budget; the governor cannot reassign his money; the legislature cannot reroute the revenue without renegotiating the bond covenants — which means buying out the bondholders, which the state cannot afford. The surplus is, in effect, a structural veto. The only way to dissolve it is to fold the authority into a larger entity, which is exactly what Governor Rockefeller did to end Moses's reign in 1968.