Maryland Code, Tax-General § 13-405

(1) compute the motor carrier tax by using a miles per gallon factor based on the best information in the possession of the Comptroller; and

(2) assess the tax due.

(1) compute the motor carrier tax by using a miles per gallon factor based on the use, in the State, of 40 gallons of motor fuel for each commercial motor vehicle in the person's fleet on each day during the period for which the records are not kept or made available; and

(2) assess the tax due.