Street Wart

During the winter I noticed a small hole in the street next to the drain-grate. The whole got bigger and bigger until one day it collapsed, forming a pit about two feet wide and three feet deep:
Beacon Street Hole
The city apparently decided it was time to do something about it. Their first step was to make it go away by dumping a huge mound of asphalt on the problem.
Perhaps there are two universal solutions to problems: (1) throw money at the problem (accepted scientific maxim), and (2) dump a huge pile of asphalt on the problem (my proposed universal solution):
Beacon Street Asphalt Pile
In any case, the problem seems to be more than just a hole in the street. They’re out there cutting and digging every day, trampling everyone’s spring flowers in the process. What are they building out there?