They had to down tools because they found roman ruins or something and consult archeology to proceed.

Whats interesting is that this bridge build effectively partitioned the city. You had to drive to the city limits to the ring road, drive around the edge to access that area. The local council found this agreeable, and they rolled out an entire traffic policy, which also reached international attention, that effectively splits the city into sectors, forcing drivers to drive around the crust to get into their destination slice.