http://www.motorists.org/chapters/alaska
I remembered this one from living there. Even if there is only 2 lane, one each direction, they have to pull off the road when able to let the other traffic past.
Twisting mountain roads with lots of rise and fall and a land yacht from the lower 48 make a lot of Alaskan Drivers wait too long.
California has the same law for all vehicles, Must Use Turnouts and allow passage.
It is NEVER enforced, unless a cop is in the lineup.