Indiana Code Title 8. Utilities and Transportation § 8-16-2-18

Sec. 18. Whenever such county, either from moneys derived from net tolls as aforesaid or from moneys paid by an adjoining state, or from both of such sources, shall have been repaid an amount equal to the amount of money contributed by such county to said state highway funds in aid of the construction of such bridge, including principal and interest, and when the state highway fund, either from money derived from net tolls as aforesaid, or from money paid by an adjoining state, or from both sources, shall have been paid an amount equal to the amount contributed by such county in aid of the construction of such bridge, plus interest thereon to the time of such repayment, then the right to take tolls on such bridge shall immediately cease and such bridge shall thereupon be declared to be and shall be a free bridge for use in interstate commerce between the state of Indiana and such adjoining state. In no event, however, shall tolls be collected for a longer period of time than is permitted by any law of congress now in force or hereafter enacted regulating the collection of tolls on interstate bridges.