Section 30A. The registrar shall not allow direct or indirect use of the computer terminals under his control, whether for inquiry into computer data files or otherwise, except by persons employed by the commonwealth or a political subdivision thereof, law enforcement agencies, the special investigative unit of the plan created pursuant to section one hundred and thirteen H of chapter one hundred and seventy-five only to the extent authorized therein, insurance companies and their authorized agents and service carriers to the extent authorized in the safe driver insurance plan and for the purposes of complying with the requirements of sections one A, thirty-four A, thirty-four B and thirty-four H pertaining to motor vehicle liability policies and the trial courts or computer manufacturers or data processing consultants under contract with the commonwealth.