In Alaska, as far as I know overnight parking is still permitted along roadside turnouts, rest stops and parking areas along the highways unless otherwise posted.....
It is also still the law in Alaska to pull off any roadway or highway and rest when any driver gets too fatigued or tired....In case any law enforcement officer should question or harp about parking overnight in some public domain spot, just use this excuse on them.
In the past 10 years I noticed there are a lot more no overnight parking signs along the roadways in BC, and in the Yukon I now see many no overnight parking signs particularly on the Alaska Highway between Haines Junction and Teslin that never used to be there.
However, you still see the practice of some travelers parking in these places overnight, especially semi truck drivers in the larger turnouts...and I have yet to this day witness seeing or hearing any enforcement done anywhere along the Haines, Klondike, Cassiar or Alaska Highways of people parking overnight in these roadside places.
Anywhere along my travels of southern BC or southern Alberta (mainly Trans Can highway 16 and south of there), I never see anyone park overnight along those roadside areas with signs posted.
Call me guilty, every now and then I will overnight along these roadside spots if I am too tired or it is just too dark if I am not too familiar with an area or any known hazards that are around such as wildlife migration, construction zones, etc.
In these roadside spots with no one present (that I am not familiar with), I will decide by feel if I think it is ok to overnight or not, sometimes I will park there and other times I will move on.....In case I ever get questioned about it I would say I had mechanical issues or that a semi parked right in front of the sign as I never seen there was a no overnight parking sign present.
So pretty much I can say I have yet to be contacted or bothered about parking overnight (with no overnight parking signs posted in Canada) along a roadside anywhere north of Trans Can highway 16...although I do not hardly ever as most of the time I can generally reach all my other familiar permitted spots between driving stretches.