(a) A port authority may collect a fee for permits issued under this subchapter. Such fees shall not exceed $120 per trip.
(b) Fees collected under Subsection (a), less administrative costs, shall be used solely to provide funds for the maintenance and improvement of state highways subject to this subchapter. The administrative costs, which may not exceed 15 percent of the fees collected, may be retained by the port authority. The fees, less administrative costs, shall be deposited in the State Highway Fund.