Ok, now I have to know - which bridge? When you mentioned sewer work, I was thinking perhaps the bridge over Johnson Creek as a detour around the closed part of the Springwater Corridor Trail.

BTW, the 5 car slow moving vehicle thing is not the law in Oregon. You are not required to pull over, although if you are out cycling in the rural areas with only a 2 lane road, it is courteous to pull over to let back-ups of cars pass.