Ohio Rev. Code Ann. § 5537.13
(C)
(1) Except as necessary to comply with covenants in bond proceedings in existence before July 1, 2013, for calendar years 2013 through 2023, the commission shall not increase the toll rates for any class of passenger vehicle as fixed on July 1, 2013, when both of the following apply:
(2) Subject to division (C)(1) of this section, tolls shall be so fixed and adjusted as to provide funds at least sufficient with other revenues of the Ohio turnpike system, if any, to pay: