I will add that this area is unique terrain and very scenic thru the Fraser Canyon area....it took a lot to build a highway thru there as those tunnels add so much character too....everyone is spot on with their posted comments as this stretch of highway is one you better be alert if driving.
I driven this route a total of 12 times (6 round trips) between 1985 and 1991, although I haven't been thru the area since.
In the mid 1980's, the canyon area corridor was light to moderate traffic during the day, when the late 1980's rolled around the traffic was moderate to heavy as I was trying to make sense of what happened with all this increased traffic I was in shock it was so busy.....I can imagine what it is like today.
Then again in 2012, the traffic on Trans Can 1 between Kamloops to Revelstoke was streamline heavy bumper to bumper and it was just non stop busy traffic at that, worse than I expected upon my first time in the area which I did not expect over 90 percent of this stretch was only a two lane highway.
I realized that the southern region of British California does not have enough highways to accommodate today's traffic anymore.....all the major British Columbia highways in the southern portion can get so congested at times too but at least most of the time the traffic is flowing.
As noted, it does get very hot in the canyon area on the sunny days as I experienced 100 degree temperatures on two occasions - I would have posted the exact same thing Flatfoot-Rogue had, reference to make sure upon having a sound rig with adequate cooling on hot days.
I started taking pictures for the first time on road trips in 1991 as I only have a few location pictures of the area of what it looked like then.....
Aug 1991 - Mile 67 - km 108 Trans Canada Hwy 1 -Fraser Canyon-
just north of Yale Tunnel :
Aug 1991 - Mile 77 - km 124 Trans Canada Hwy 1 -Fraser River- Alexandria Bridge :