Right after the Matanuska Glacier, we ran into some roadwork. It's a good wait until the pilot car comes through to let you go, and in the wait time, folks seem to write their initials inrocks on the roadbank. This was a teen group who were hustling about making the club logo in rocks before the traffic resumed.
In many parts of Alaska, the gravel for the roads is mined on-site, or very close by. The road into Denali National Park, for instance, is covered in gravel that's mined within the park.