Idaho Code § 49-601: Application.

The provisions of this chapter relate exclusively to the operation of vehicles upon highways, except where a different place is specifically referred to in a given section.

They shall not apply to persons, motor vehicles and equipment while actually engaged in work upon a highway, or to owners or operators of a ditch, canal, conduit or drain while engaged in work within and pursuant to a right-of-way for a ditch, canal, conduit or drain, but shall apply to persons, owners, operators and vehicles when traveling to or from that work.