Learning lessons from landslides on highways, the 217-km Shimla-Mataur fourlane highway project will be the first national highway where the grid-based road technology will be used. It aims at making fragile hill safe from landslides that cost state treasuries crores of rupees every year.
Road professionals have raised a pitch for the grid-based highways to check the rising road fatalities and damage to roads due to landslides. “We have proposed to build the Shimla-Mataur highway on the grid-based technology to save the hills from vertical cutting,” said YA Raut, manager, technical, NHAI. “We construct the first lane at a higher slope and then second lane at a lower slope. This becomes a grid of two separate roads running parallel,” he said. Raut said the idea would help maintain the natural hill slope and prevent landslides or collapse of hill while cutting. “First, we cut one lane at a higher side for some length, then the second lane is constructed at a 10 m distance at a lower side. This way vertical cutting of the hill is avoided for the road,” he added.
The cost of grid-based road technology was about 20 per cent higher. “The cost is higher because we need to acquire about 60 m width for the grid of roads, whereas in the present case, we can construct four lane just acquiring 32 m or so,” Raut said. The Indian Road Congress, an apex body that governs the construction of the highways, had also adopted the grid-based design of roads which had been standardised in the West, revealed NHAI engineers. “We need to rethink on the proposed 63 highways, including Kalka-Shimla and Kiratpur-Manali highways, being built by the NHAI and three double-lane highways being built under the Border Roads Organisation (BRO) in the borders areas of Lahaul-Spiti and Kinnaur,” they added. In 1988, Matiana landslide killed bus passengers on the Shimla-Narkanda highway. The 1994 Luggarhati landslide killed 42 workers on the Kullu-Manali highway, while recent Kotrupi hillslide killed 46 passengers near Mandi.
About the grid technology
- Builder constructs the first lane at a higher slope and then second lane at a lower slope. This becomes a grid of two separate roads running parallel
- It aims at making fragile hill safe from landslides that cost state treasuries crores of rupees every year
- The cost of grid-based road technology is about 20 per cent higher
- The NHAI needs to rethink on the proposed 63 highways, including Kalka-Shimla and Kiratpur-Manali highways, and three double-lane highways being built under the BRO in the borders areas of Lahaul-Spiti and Kinnaur