NEW DELHI: The road transport and highways ministry has admitted design failures, weak quality assurance and over-reliance on builders as some of the factors for certain newly built highway stretches with concrete pavement collapsing in rain-prone and low-lying areas, according to the latest report of Public Accounts Committee (PAC) of Parliament.Raising concerns over the “indiscriminate shift” from bituminous to concrete roads without adequate assessment, the committee said this has led to poor-quality outcomes, delays and potential wastage of public funds. The panel has recommended that the ministry and NHAI adopt a mandatory, evidence-based framework for selecting pavement materials – bituminous, concrete, or otherwise – based on site-specific technical and environmental assessments. This, it said, should be integrated into the preparation of DPRs. The panel referred to specific instances, including a section on the Delhi-Vadodara Expressway that got damaged. “These roads, which were expected to offer long-term service with minimal maintenance are found to have developed premature cracks, surface distress, and failures in pavement quality concrete, often within a short period of completion,” the report said.The PAC has also called out the ministry on the practice of subcontracting – primary contractor assigns or outsources its work to other parties. It has recommended that the ministry discourage subcontracting beyond ‘one’ level.