NH-66 Safety Overhaul: Expert Teams Inspect Earth-Fill Flyovers After Kollam Collapse

Following structural concerns on the Kollam-Mylakkad stretch, the NHAI is re-evaluating the design of earth-filled elevated corridors along the busy national highway.

The recent structural failure of an earth-filled elevated section on the ദേശീയപാത 66 (National Highway 66) at Mylakkad has triggered a high-level safety audit. The National Highways Authority of India (NHAI) has now mobilised an expert committee to conduct a comprehensive stability assessment of similar structures across the route. This intervention follows a direct directive from Union Minister Nitin Gadkari in the Lok Sabha, where the feasibility of replacing earth-fill embankments with pillar-based flyovers was raised as a critical safety necessity.

The technical scrutiny is being led by a committee of experts, including senior faculty from IIT Delhi and the Head of the Civil Engineering department at IIT Palakkad. To support this rigorous process, the NHAI has enlisted eight geotechnical agencies. These teams are currently conducting detailed site visits, soil testing, and surface analysis to determine if the existing designs can withstand current and projected traffic loads.

The expert committee has already proposed significant structural modifications for several stretches in Kollam. Their recommendations include replacing earth-filled segments with pillar-supported elevated structures at Mylakkad (120 meters), Kadavoor (440 meters), and two 80-meter segments at Mevaram. Furthermore, the panel has suggested extending pillar-based flyovers on both sides of the Neendakara bridge and the KMML underpass to ensure better load distribution and long-term durability.

The Bigger Picture: Why it matters

This shift toward pillar-based construction signals a potential pivot in how India approaches highway engineering in terrain-sensitive regions. While earth-filled embankments are historically cheaper and faster to construct, they are increasingly proving vulnerable to soil instability and drainage-related degradation in Kerala’s unique topography. If the NHAI adopts these recommendations, it would set a new precedent for infrastructure projects in the state, prioritizing safety and resilience over initial cost-efficiencies. This audit serves as a litmus test for the long-term viability of the ongoing primary infrastructure push under the original highway development plans.

The technical reports and the proposed design shifts are currently under the final review of the NHAI. The speed at which these agencies move will determine how soon the affected stretches of the highway can be cleared for full-scale traffic. For now, the focus remains on ensuring that the structural integrity of the project matches the heavy-duty demands of a primary corridor.