This bridge over the Susitna River is the longest wooden bridge I've ever seen. The planks are huge! They're about 14 inches wide and 4 inches thick, and underneath them are 2x6s running perpendicular, with the two-inch face up (giving a 6" thick platform for the upper planks). The picnic tables in many places are also made out of 4x12 boards. What's amazing is that the wood has to be imported, because there just aren't any trees that big in this area. The spruces are the biggest trees, but they're skinny.
The river is huge: fast and wide, but no rapids near the bridge. The area felt very calm. We bundled up in our down jackets and stood on this bridge for 15 minutes or so, and not a single car came by. Not a very busy highway! I think that a highway in Alaska is any road that doesn't dead-end at a town. There are nine highways in Alaska, I believe. Oh, but three of those do dead-end, at Seward and Homer on the Kenai Peninsula, and at Valdez, so I guess that blows that theory.