The tunnel, built with ultra-modern specifications, is located in the the Pir Panjal range of the Himalayas at an altitude of 3,000 metres(10,000 feet). It is a horse-shoe shaped, single-tube, double-lane tunnel with a roadway of 8 metres and an overhead clearance of 5.525 metres.
Global technology giant Siemens has provided the technology for the tunnel's automation across various processes including lighting.Sunil Mathur, managing director and CEO, Siemens Limited, told Business Standard that the tunnel has a fault-tolerant automation system that minimises the probability of a production failure to nearly nil, playing a decisive role when it comes to achieving maximum productivity. Some of the key safety features include -- entry barriers at both portals, telephone connections at every 150 meters for emergency communication, fire hydrant mechanisms at every 60 meters, auto incident detection system with CCTV cameras at every 250 meters, air quality monitoring at every 1 Km, evacuation lighting or exit signs at every 25 meters, broadcasting system throughout the tunnel, fire-rated dampers at every 50 meters. The tunnel also has cameras at 60-meter intervals.
The tunnel, built by the Border Roads Organisation (BRO) at a cost of about Rs 3,300 crore, is extremely significant from the point of view of the country's defence. SAIL supplied steel for the construction of the tunnel, which will be conducive to all-weather traffic, connecting Manali to Lahaul and Spiti Valley in Himachal Pradesh throughout the year.
The Atal Bihari Vajpayee government had taken the decision to construct the strategic tunnel below the Rohtang Pass on June 3, 2000, and the foundation stone for the access road to the south portal of the tunnel was laid on May 26, 2002. Vajpayee got the idea for constructing the tunnel on a suggestion from his friend Arjun Gopal of Tashi Dobhe village in Lahaul, Himachal Pradesh, Chief Minister Jai Ram Thakur said. The Modi government decided to name the Rohtang Tunnel as Atal Tunnel in December 2019 to honour the former prime minister who passed away in 2018.