The two longest tunnels will be of 2.27 km each between Taradevi and Shogi and Kandaghat and Solan.
The state government wants that the highway be realigned and include more tunnels to reduce the distance by another 20 km.
On 27 September 2016, tenders were invited for the construction of Solan-Kaithlighat section, with last submission date as 11 November 2016.
As of February 2017, the project is facing delay due to legal issues and construction works on the first phase are kept on hold.
Geologists argued that the cutting of the mountains for highway construction had destabilized the slopes.