Section 25. Except as hereinafter provided, no person shall operate a snow vehicle or a recreation vehicle upon any state, county, city or town way in the commonwealth, nor on the plowed snowbanks of such ways, nor upon any other public way, nor upon the right-of-way limits of a controlled access highway. In the event of emergency conditions as determined by the registrar of motor vehicles which render public ways impassable to conventional motor vehicles, the registrar may, without prior notice or public hearing, promulgate temporary emergency regulations to permit the operation of snow vehicles or recreation vehicles on such ways, but only for such purposes as may be necessary for the health and safety of persons in the area of such emergency; and such regulations shall be rescinded promptly upon the abatement of said emergency.

In the event of a determination by a mayor or board of selectmen, that because of emergency conditions, public ways within a city or town are rendered impassable to conventional motor vehicles, such mayor or board of selectmen, may, without prior notice or public hearing, authorize the director of the local organization for civil defense or the chief of police in said city or town to grant permits to civil defense volunteers to operate snow vehicles on such ways for such purposes as may be necessary to ensure the health and safety of the public. Such permits shall be rescinded promptly upon the abatement of such emergency conditions.

No person under 16 and one-half years of age shall operate a snow vehicle or a recreation vehicle across or on a public way unless the operator holds a valid license or right to operate a motor vehicle or is directly supervised by a person 18 years of age or older. An operator of a snow vehicle or a recreation vehicle that meets the requirements of the preceding sentence shall, after coming to a full stop, cross, as directly as possible, a public way; provided, however, that for recreation vehicles, the public way and the crossing shall be marked and approved for use by recreation vehicles by the applicable state or local authorities as part of a publicly or privately authorized recreation vehicle trail system. An operator of a snow vehicle or a recreation vehicle shall make the crossing safely and without interfering with the free movement of vehicular traffic. An operator of a snow vehicle or a recreation vehicle shall yield the right of way to all other vehicular traffic when making such crossing; provided, further, that an operator shall not cross a controlled access highway.

Whenever it is impracticable to gain immediate access to an area adjacent to a public way where a snow vehicle or recreation vehicle is to be operated, said snow vehicle or recreation vehicle may be operated adjacent and parallel to the travelled portion of such public way or upon, but to the extreme right of, such travelled portion for the purpose of gaining access to the area of operation. This paragraph shall apply to the operation of a snow vehicle or recreation vehicle from the point where the snow vehicle or recreation vehicle is unloaded from a motorized conveyance to the area where the snow vehicle or recreation vehicle is to be operated, or from the area where operated to a motorized conveyance when such loading or unloading cannot be effected in the immediate vicinity of the area of operation without causing a hazard to vehicular traffic approaching from either direction on said way. Such loading or unloading must be accomplished with due regard to safety, at the nearest possible point to the area of operation. This paragraph shall also apply to any portion of a public way designated by the governmental entity with jurisdiction over the public way, with approval of the chief of police of the municipality in which such portion lies, to permit travel by a recreational vehicle from 1 authorized operating area to another or to permit access by a recreational vehicle to essential services, including fuel, food and lodging, from an authorized operating area. The designated portion shall be the minimum distance necessary to permit such travel or access but shall not exceed 4 miles.

Except as herein provided, no snow vehicle or recreational vehicle shall be operated on the main traveled portion of a way, or on that portion of a way that has been plowed or on a snow bank immediately adjacent to the plowed portion of the way.

Snow vehicles or recreation vehicles may be operated on any way that is not maintained or used for the operation of conventional motor vehicles.

Any vehicle registered under chapter ninety B may be pushed across any way. It may also be pushed adjacent to such way provided at no time shall such vehicle interfere with the normal flow of traffic.