Cracks have developed along the entire Dhaka-Chittagong highway within a year of its expansion work completion.
This has forced the authority concerned to undertake a maintenance project for five years, sources said.
Though Roads and Highways Department (RHD) has already started process to take up Tk 7.0 billion maintenance project for keeping the country's economic corridor fit for the next five years, experts, however, said it would not help improve vulnerable condition of the highway.
The Dhaka-Chittagong highway experiences most overloading as 80 per cent of the country's cargoes use this corridor to reach and come from the Chittagong port.
They said the life of the old two lanes of the four-lane highway is over after its construction in 1980s.
As the Dhaka-Chittagong four-lane construction work was completed without reconstruction of the old two-lane road, engineers said, the maintenance project would not save the corridor from further damages.
"Life of the old two lanes of the Dhaka-Chittagong highway has almost been over. But its reconstruction was not undertaken during the four-lane project. So it cannot be maintained by continuing overlaying," said an engineer involved with the Dhaka-Chittagong four-lane project.
Under the Tk 38 billion Dhaka-Chittagong four-lane project, new two lanes were constructed either on one side or on both sides of the existing two-lane road and finally overlaying was done over the entire four-lane.
Although some major repair works on the major highway were done during the time of constructing the first phase of the four-lane work from Katchpur to Daudkandi, sources said life of that part of the road also ended due to overloading of vehicles.
According to RHD, imposing different fines against overloaded cargoes on the highways could not check overloading.
Besides, cargo operators did not follow the directive by adding an axle or two wheels in the middle of all cargo vehicles for saving roads and highways.
Some insiders also blamed poor construction work and poor planning of the highway for early deterioration of road condition.
They said the RHD had completed 80 per cent of 193- kilometre work from Daudkandi to Chittagong city in phases by June 2016.
Finally, it completed the entire artery by June this year. But it allowed the highway to be used during all these years.
Sources said without completing the entire road, RHD counted fiscal year 2016-17 as defect liability period for the project's three contractors and has taken new maintenance project.
However, an engineer of RHD Comilla zonal office said the new maintenance project for the Dhaka- Chittagong highway has to abide by the department's decision for all national highways.
As per the RHD decision, the contractors with whom the Division signs contract to construct any four-lane work will be responsible for carrying maintenance work for five years.
The same contractor will carry out the maintenance work under a separate project after the end of 'defect liability period'.
In case of Dhaka-Chittagong four-lane project, the official said due to lack of such contract with Chinese and local contractors, RHD has decided to appoint a fresh contractor.
According to the Comilla zonal office, as the overloaded cargo vehicles usually use the right side of both sides' lanes, cracks have been visible all along the corridor.
Preferring not to be named as the official is not spokesperson of the RHD, he said a single cargo that overloads 20 per cent of the road's allowable level causes loss of the life of a road by almost half. There are thousands of vehicles plying on the highway continuing to make the corridor vulnerable.
The Dhaka-Chittagong four-lane project is the RHD's first big project, designed without proper planning and studies causing the project cost to double in more than 10 years.
Though all other national highways' expansion projects are now being taken with the design of service lanes and reconstruction of existing two roads, it was not done in this project.
Sources said the Ministry of Road Transport and Bridges has already met RHD engineers several times to review the road condition of the prime highway, but is yet to find a solution for undertaking reconstruction work.
Different suggestions were placed during these meetings.
Sources said as the four-lane roads are now being constructed with the provision of service road for slow-moving vehicles, the RHD also is exploring the option to construct the service road for the Dhaka-Chittagong highway first and then to work on the old two-lane reconstruction work.