Enjoy this infamous road.
From the USDA Forest Service site of the Nez Perce National Historic Trail:
Lolo Motorway (Forest Road 500) is a narrow, winding primitive
road that dips into saddles and ascends again onto ridgetops. This
single-lane road, partially built by the Civilian Conservation Corps
in the 1930s, offers the more adventurous traveler a more tangible
experience of the Nez Perce National Historic Trail.
The road is generally free from ice and snow by mid-July and
usually accessible into October. A vehicle with high clearance
is recommended. Taking RVs or towing trailers on the road
is not recommended. You’ll find no services along the
Motorway; be sure you take plenty of fuel, food and water.