The construction of Hindustan-Tibet Road started in 1850-51 commencing from Kalka and first lap was up to Shimla. The road up to Shimla came to be used for traffic by 1860. The NH22 starts at Ambala in Northern Haryana as an offshoot of NH1. The NH22 runs north towards Zirakpur, outside Chandigarh. This first 40 KM stretch, running partly through Eastern Punjab is named as Ambala Chandigarh Expressway is a modern and well maintained four lane section with several bridges and 03 major flyovers. At Zirakpur it meets NH64, and turns North-East through Panchkula to Pinjore, where the NH21A heads North-West, then to Kalka and Parwanoo. The expressway has now been extended to bypass to town of Pinjore and Kalka which were previously a major traffic bottleneck point. After Kalka, the highway enters Himachal Pradesh and as the terrain changes it becomes all mountainous roads with extensive hairpin turns. It continues North-East to Solan, and then North to Shimla,where it joins the NH88 between Kalka and Shimla, several sections run near the kalka-Shima Railway. From Shimla, it heads approximately North-East towards the Chinese frontier, reaching the border town of Khab just before the Line of Actual Control. Beyond Khab, the road runs for short distance through Namgyal to the Shipki La pass, where it enters Chinese territory.

Pros:

• A picturesque natural beauty as one enters hill.

Cons:

• Time consuming and road tends to get blocked during monsoon.