Del. Code tit. 30 § 5208
Every motor carrier subject to the tax imposed by this chapter shall on or before April 30, July 31, October 31 and January 31 of every year make to the Department of Transportation such reports of its operations during the quarter ending the last day of the preceding month as the Department of Transportation may require and such other reports from time to time as the Department of Transportation may deem necessary. The Department of Transportation, by regulation, may exempt from the quarterly reporting requirements of this section those motor carriers operating solely within this State and require in such instance an annual affirmation, if in its discretion the enforcement of this chapter would not be adversely affected by such a regulation. The Department of Transportation is further authorized by regulation to exempt from the quarterly reporting requirements of this section and to require in such instances an annual affirmation of motor carriers licensed in this State who perform substantially all of their travel in this State; provided the Department of Transportation is assured that a sufficient amount of fuel is purchased in this State which is commensurate with the motor carrier's operations on highways within this State.
The Department of Transportation may, by regulation, exempt certain other motor carriers from the quarterly reporting requirements of this section. The Secretary of the Department of Transportation shall promulgate regulations which will set forth and determine the minimum amount of annual net fuel use taxes due the State which, if not exceeded by the estimate of any motor carrier, will exempt that motor carrier from quarterly reporting requirements of this section. The motor carrier who desires to be exempt from the quarterly reporting requirements must, on the motor carrier's first application for registration in a given registration year, attest that the motor carrier's estimated net fuel use tax in said year will be less than the threshold amount established by the Secretary of Transportation's regulation. The Secretary of Transportation is further authorized to allow by regulation in such instances, the filing of an annual report due with remittance on or before January 31 following completion of said registration year.
30 Del. C. § 5208