Tamil Nadu Gives In-Principle Approval for 18.4-km Double-Decker Elevated Corridor on GST Road

The Tamil Nadu government has granted in-principle approval for the construction of an ambitious 18.4-km double-decker elevated corridor along GST Road, connecting the Kalaignar Centenary Bus Terminus at Kilambakkam with Chettipunniyam near Mahindra City. The project is expected to significantly ease congestion on one of Chennai’s busiest southern gateways while future-proofing the corridor for mass rapid transit.

The elevated road project will be implemented under the leadership of the National Highways Authority of India. As per the current proposal, the lower deck will feature a six-lane elevated highway designed to streamline long-distance and suburban traffic movement on GST Road. Importantly, the structural pillars will be engineered to support a Metro rail viaduct in the future, making it a fully integrated transport corridor.

This dual-use design positions the project as one of the most advanced urban infrastructure initiatives in the country. Once constructed, the 18.4-km stretch will surpass the existing national record of a 5.6-km double-decker Metro viaduct in Nagpur, highlighting the scale and complexity of the development planned for Chennai’s southern suburbs.

The in-principle clearance followed a high-level coordination meeting involving officials from the state highways department, Chennai Metro Rail, and NHAI. Earlier concerns related to Metro alignment and integration were addressed during these discussions, paving the way for the project to move forward without design conflicts.

According to senior officials, the detailed project report is currently being revised to incorporate the agreed structural and alignment changes. Once the revised DPR is finalised, the project will move into the tendering stage, with active support from the Tamil Nadu government expected during execution.

Infrastructure experts believe the elevated corridor will play a critical role in supporting rapid residential, commercial, and industrial growth around Kilambakkam, Tambaram, and the Mahindra City belt. By combining road and rail planning within a single corridor, the project reflects a long-term, sustainable approach to urban mobility in the Chennai metropolitan region.