These days the city is repaving the main road close to my office. Looks like the rainwater drainage system is being upgraded and curbs and drains are added to manage the flow of rain water. Few casual google searches helped understand some of basic cross section for a new asphalt road. An image of the search is attached below.
Below is a picture from the current repaving of the road, where an excavator is scoping out the dirt and trucked out. Then the dirt is replaced by different types of crushed stone.
Questions: What is the engineering explanation for all this additional rework? To begin with was the road sinking? To the casual user the road appeared to be perfectly in good shape, thus a waste of tax payer money. How can the additional cost be justified?