The 700 metre underpass will be six lanes and the project cost is Rs 350 mn. It will remove the only signal on the 22 km Hebbal to Sadahalli section and provide uninterrupted airport access. The contract has been awarded to Vidya InfraBuilt Pvt Ltd and design work is complete.
Excavation is expected to begin in September 2026 after the monsoon and construction will use a cut and cover method. NHAI aims to complete the work before the Aero India show, which is likely to be held in February 2027. To maintain traffic flow during construction, service roads on both sides will be expanded to four lanes.
The grade separator was first proposed nearly a decade ago and the original flyover plan was reworked as an underpass to limit land acquisition and improve flow. Toll revenue figures underline corridor use: Devanahalli plaza collected Rs 3.08 bn in 2023-24 and about Rs 15.77 bn over the last ten years. Current Sadahalli tolls are Rs 120 for a one-way car journey, Rs 185 for a return trip and a monthly pass for 50 single journeys costs Rs 4,070.
Officials noted that rapid real estate growth in the area will increase traffic volumes and underscored the need for the underpass. Preparatory works during the monsoon will focus on minimising disruption while allowing main construction to proceed in the drier months. The scheme is described as a strategic improvement to connectivity between the city and KIA.