17 Del. C. § 420

(a) The Department may make and enforce such rules and regulations and establish, levy and collect (or authorize by contract, franchise, lease or otherwise, the establishment, levy and collection of) such tolls, rents, rates and other charges for the use of any toll crossing operated by the Department or any improvements or extensions thereof as it may deem necessary, proper, desirable and reasonable, and the Department may pledge such tolls, rates, rents and other revenues, or any part thereof, either presently received or to be received in the future, or both, as security for the repayment with interest of any moneys borrowed by it or advanced to it and as security for the satisfaction of any other obligation assumed by it under the authority of this chapter.

(b) Such tolls, rates, rents and other charges shall be so fixed and adjusted so as to provide funds at least sufficient, together with any other revenues of the Department, to pay the cost of maintaining, repairing and operating the toll crossings operated and maintained by the Department, and the principal of and the interest upon the outstanding revenue bonds of the Department, subject, however, to any applicable law or regulation of the United States of America now in force or enacted or made after July 27, 1955. Such tolls and all other revenues of the Department shall not revert to the General Fund of the State Treasury but shall at all times be available to the Department for the purposes set forth in this chapter. Such tolls, rates, rents or other charges shall not be subject to supervision or regulation by any other commission, board, bureau or agency of the State.

(c) The Department shall not impose, establish, levy or collect a toll that it would otherwise be permitted to impose, establish, levy or collect under this section, for any emergency vehicle of a volunteer fire company or volunteer ambulance company, or any emergency vehicle engaged in the ordinary course of business of a volunteer fire company or a volunteer ambulance company.

(d) The Department shall not impose, establish, levy or collect a toll that it would otherwise be permitted to impose, establish, levy or collect under this section for any emergency vehicle of a police agency, including marked, semi-marked or unmarked vehicles, engaged in the ordinary course of business of a state, county or municipal police agency.