The sign of an area with a dense population where people operate within close proximity to people-squashing-machines, and the people have rightly decided that reducing the severity of any potential people-vs-people-squashing-machines incidents is worth far more than the modest reduction in travel time for the occupiers of the people-squashing-machines, most of which never spend much time at 60km/h anyway due to congestion.

Frankly, anyone driving at 60km/h through narrow streets isn't driving with due care and consideration for the surroundings anyway.