75 Pa.C.S. § 9608

Every motor carrier subject to the tax imposed by this chapter shall, on or before the last day of April, July, October and January of every year, make to the department such reports of its operations during the quarter ending the last day of the preceding month as the department may require and such other reports from time to time as the department may deem necessary. The department may by regulation permit motor carriers whose estimated annual liability under this chapter is $250 or less to file its report on an annual basis.