I forget the technical name.... chip and seal?
All I have ever seen on BRP is this terrible combination of gravel (large and small) and pouring a ton of hot gooey tar/asphalt all over it, and it is a stinking mess until 10,000 cages drive over it for a few days, and you do not want to be on it in a bike anytime soon after it is done. I've been up there several times, and had to just turn around and go back the way I came. The one time I did ride on it, the bike was sinking in, and it was hours and hours of hard cleanup (after it dried). They don't use the big heavy rollers to pound it down (maybe they can't get them up there), they use private vehicles to do it for them.
You can go on-line to try to find updates on BRP chip and seal sections, and wherever you may get on BRP, ask the guy (gal) at the gate; they usually know if and where it is going on... they usually can give you the mile markers affected. Go around, or another way.

Also, anyone who rides the hills and mountains will tell you to watch out for the tightest inside and outside corners of all roads all the time. Erosion, water travel, gravity and cars/trucks put lots of loose gravel and sand in those corners all the time.