Del. Code tit. 17 § 1728
The Delaware River and Bay Authority shall not increase any rate of bridge toll charged as a volume discount rate from the rate in effect on the earlier of the effective date of the legislation amending the Delaware-New Jersey Compact as adopted by (i) the 135th Delaware General Assembly or (ii) the New Jersey Legislature, for a period of 10 years following such date, if the increase would cause such volume discount rate to exceed 25 percent of the basic toll rate charged by the Authority for individual bridge crossings by passenger automobiles, provided that the Authority may raise such volume discount rate in excess of this 25 percent limitation to the extent that such increase is determined by the Authority to be reasonably necessary for the protection of the Authority's bondholders in accordance with Article XI of the Delaware-New Jersey Compact.
17 Del. C. § 1728