The authorities concerned will have to review the feasibility study and detailed design of more than 80 per cent of the country's highways due to a recent decision to change service lane design.
The Roads and Highways Department (RHD) has recently decided to construct two-lane service roads on both sides of the existing highways which will be constructed at the same level of the main arteries, officials said.
Earlier the government had decided to construct the service lanes below the level of the main arteries.
Due to the change in the decision, the feasibility study and detailed design of more than 80 per cent of the country's 1,752 km highways will need to be reviewed within only five years of completion of the existing study and design.
The new decision would also threaten a study project under which 590 km or seven highways were being studied as the project is supposed to complete in June next.
Sources said the design of 1,752 km highway or 13 highways was done in 2015 based on the decision to construct the service lanes below the level of the highway for ensuring road safety and access control on it by slow-moving vehicles.
They said more than 300 km highway under different projects have already been reached construction stage.
Of these, 55 km Dhaka-Mawa-Bhanga highway and 75 km Tangail-Elenga highway four-lane work have reached near completion. The Elenga-Hatikamrul-Rangpur highway four-lane work is now under construction level.
RHD officials said the decision to keep the service lanes at the same level of national highways was taken to lessen the construction cost as it needs more land on both sides of the highways to separate the lanes for making a slop.
They argued that the land acquisition is not only complicated but also getting expensive in the country.
They, however, said road separation between the highways and service lanes would be made by putting barriers all along the highways.
"The Dhaka-Sylhet highway design has already been changed as per the changed decision,' said an official.
He said the highways which are yet to go to implementation stage will also be reviewed at the time of project preparation for construction.
Meanwhile, RHD has included two roads - Rangpur-Teesta-Burimari road and Daulatdia-Faridpur-Barishal road - under its second project under which 590 km highway feasibility study have been carried out.
Sources said that of the left 1,431 km highway studied in the first phase in 2015, the project will now review 270km road. The rest would be done at the time of implementation.
BUET Professor M Shamsul Hoque said both the designs would create barrier for the neighbourhood - though one is suitable for expressway or access control highway and another in the context of cost effectiveness.
He rather suggested developing the access control highway or expressway on elevated concept to save land mainly agricultural land.
The RHD completed the feasibility study and detail design of 1,752 km national and regional highways on various corridors under a protect titled Technical Assistant for Sub Regional Road Transport Preparatory Facility funded by Asian Development Bank.
