Gee, ya think?
Don't know why they are surprised at the increasing costs for this project. It is what happens when a project of this magnatude is undertaken. Go figure.
I don't live in Des Moines, but grew up there & I know the area this is being done in. I wish them luck.
Oh N_C as an engineer involved with transportation improvements I understand the increases. At times promoters of a project are unconsciously optimistic about costs in order to get the idea past gatekeepers. At times towns or private groups that can block the project insist that they be included in what was once a simple project. People who do not like the idea can delay the project for the best of reasons raising costs. Et cetera, et cetera.
Some relatives of mine who needed some retaining walls on their steep property are now trapped in a seemingly endless series of problems with city agencies. With costs sky-rocketing. Recently they found that if he and she had just done the work themselves with pick and shovel no one could have stopped them.
In your area is there any possibility of just using a tiny bull-dozer to create a cheap dirt-cheap path. Once it exists improvements are much easier to arrange around here. When fill is needed it can sometimes be gotten for free from developers and construction companies who need a place to dump clean rock and dirt.