Comment by gamblor956

Believe it or not, the people that design and build these bridges have a lot more experience than you do. So if they're doing something that doesn't make sense to you, you should ask yourself what you're missing, and not question their basic competence.

The point isn't just to make a bridge, or they would use a simple concrete bridge.

The point is to make a bridge that is preferable to crossing the highway. And to do that they need to landscape it as if it were part of the landscape. That takes more time because the bridge needs to be stronger to handle the weight of the soil and plants, which means the design, permitting, and construction phases are longer.

They're closing the surrounding road for the soil movement part of the project because that part of the project entails risks of landslides, and it's safer to just close the road. However, the road won't be closed the entire time; it will only be closed for a few hours at a time. The months-long period is just the part of the project when the road will be subject to potential closure.