Section 12. The licensing authority in any city or town may, in respect of matters not treated of in the provisions of law governing the operation of motor vehicles under this chapter or rules established by the department, adopt rules and regulations governing such operation. After the adoption of any such rules and regulations, any person operating such a motor vehicle as authorized by this chapter, or a railway or railroad company operating a railway or railroad in such city or town, or any twenty residents thereof, may petition the department for the alteration, amendment or revocation of any such rule or regulation.
The department, upon such petition, after notice to the licensing authority and a hearing, may alter, amend or revoke such rule or regulation and establish in place thereof rules and regulations thereafter to be observed in such city or town. Thereafter the department, upon its own initiative or upon petition of the mayor of such city or the selectmen of such town, or of any person so operating any such motor vehicle in such city or town, or of a railway or railroad company operating a railway or railroad in such city or town, or of any twenty residents thereof, after notice to the licensing authority of such city or town, may alter, amend or revoke any rule or regulation established by the department, and may adopt rules and regulations in substitution thereof. Rules and regulations prescribed by the department under this section shall not be subject to amendment or repeal by a city or town or by the licensing authority thereof.