Flyover construction and traffic congestion

WE are constrained to say that the traffic mess in Moghbazar and Mouchak, where the system is in a shambles because of the under construction flyovers, speaks volumes about the lack of planning on the part of the authority.  Construction of flyovers is a normal affair in any city. But perhaps nowhere more than in Dhaka have the public in general been put to so much inconvenience. We wonder whether the authorities are managing the construction of flyovers in the capital efficiently, if at all. We are inclined to think that it is not.  
Given that the capital is over congested as it is, movement of traffic has been further impeded to the point of being a nightmare for the people. And whatever room there is for vehicular movement has been taken up by construction debris, work materials and inefficient management of space. Apparently, very little planning has gone into this aspect. We feel that the public is always prepared to accept a degree of hardship provided there is a modicum of effort to ease traffic movement during the time of the construction. It seems that public interest is of little importance to the authorities.
Should not the authorities have prepared the alternative roads before starting on the main job, as is done in all other cities of the world?  And the problem seems to linger because of the inordinate time overrun in all the flyover constructions. We would hope the authorities concerned will address the problem immediately.