No motor vehicle or trailer except (i) a vehicle used solely for official business by any police department of the commonwealth or its political subdivisions or by any railroad police department or college or university police department whose officers are appointed as special state police officers by the colonel of state police pursuant to section sixty-three of chapter twenty-two C and subject to such special rules and regulations applicable to such college or university police department as the registrar may prescribe, (ii) a vehicle owned and operated by a police officer of any town or any agency of the commonwealth while on official duty and when authorized by the officer’s police chief or agency head and only by authority of a permit issued by the registrar, (iii) a vehicle operated by a duly appointed medical examiner or a physician or surgeon attached to a police department of any city or town only while on official duty and only by authority of a permit issued by the registrar, (iv) a vehicle operated by a police commissioner of a police department of any city only while on official duty and only by authority of a permit issued by the registrar, (v) a vehicle actually being used for the transportation of persons who are under arrest, or in lawful custody under authority of any court, or committed to penal or mental institutions, and only by authority of a permit issued by the registrar, (vi) a vehicle operated by a chaplain of a municipal police department while on official duty and only by authority of a permit issued by the registrar shall mount or display a flashing, rotating or oscillating blue light in any direction. No motor vehicle, as hereinbefore provided, requiring a permit from the registrar, shall mount or display a blue light on such vehicle until proper application has been made to the registrar by the head of the police department and such written permit has been issued and delivered to the owner and operator. Such notice shall include the place of residence and address of the owner and operator of the vehicle for which such permit is issued and the name of the make, vehicle identification number and the registration number of the vehicle for which such permit authorizes the display of blue lights. Any person operating a vehicle upon which blue lights have been authorized to be mounted or displayed, by permit, shall carry such permit for said lights upon his person or in the vehicle in some easily accessible place. Upon termination of the duties of such person which warranted the issuance of the permit, the chief of police shall immediately notify the registrar, who shall forthwith revoke such blue light permit. Upon the written request of the chief of police of the town in which such permitted vehicle is registered the registrar may revoke such permit. The registrar shall revoke such permit for the unauthorized use of such blue lights and the owner and operator shall be subject to a fine as hereinafter provided. Upon revocation, the registrar of motor vehicles shall notify forthwith the owner and operator of the vehicle for which such permit was issued and the head of the police department of the city or town in which such permitted vehicle is registered. Upon receipt of his notice of revocation, such owner and operator shall forthwith deliver such blue light permit to the registrar and he shall not be eligible for reissuance of such permit without consent of the head of the police department of the town in which his original permit was issued. Nothing in this section shall authorize any owner or operator to disregard or violate any statute, ordinance, by-law, rule or regulation regarding motor vehicles or their use on ways of the commonwealth. The registrar may also make such rules and regulations governing or prohibiting the display of such other lights on motor vehicles as he may deem necessary for public safety.