No person shall operate a snowmobile upon any highway or public roadway in this state, with the following exceptions:
(1) Properly numbered snowmobiles may cross, as directly as possible after a full and complete stop, highways and public roadways, except controlled access highways, provided that the crossing can be made in safety and that it does not interfere with the free movement of vehicular traffic approaching from either direction on the highway or public roadway. It shall be the responsibility of the operator of the snowmobile to yield the right-of-way to all vehicular traffic upon any highway or public roadway before crossing.
(2) Loading or unloading shall be done without causing a hazard to vehicular traffic approaching from either direction on a highway or public roadway. Loading or unloading shall be accomplished with regard to safety, at the nearest possible point to the area of operation.
(3) The prohibition against operating snowmobiles upon highways and public roadways shall not apply to any highway or public roadway drifted or covered with snow to an extent that travel on it by other motor vehicles is impractical or impossible.
(4) Snowmobiles may be operated on that portion of a highway or public roadway right-of-way that is not maintained or utilized for the operation of conventional motor vehicles.
(5) Local authorities may, by ordinance, specifically designate public roadways upon which snowmobiles may be operated.