on the gravel sections, part of which is the ACA Great Divide route, the main traffic issue was dust. On the Inside North Fork Road, the middle section of the road is closed to cars for various reasons. It was a very rustic wilderness experience, complete with large piles of grizzly poop! The Going to the Sun Road was high traffic, but we just pulled over whenever 5 or so cars piled up behind us, and they went around. We were also helped by a construction flagman who closed the road for about 20-30 minutes after we passed through! It was a terrific experience, but a person can only see a small portion of the mostly roadless park by bike.