The latest Austrian tunnelling method and ventilation system - semi transverse type considered as safest - will be adopted for this project. Heavy snowfall in the Rohtang Pass area is a major concern, especially on the approach roads to the main tunnel. To prevent any damage to the roads and to ensure the safety of the roads and tunnel users alike, avalanche control structures are being constructed. The design for these structures is being provided by the Snow and Avalanche Study Establishment of DRDO.