The road from Manali follows the Solang Valley-Atal tunnel-Gramphu-Batal-Kunzum Pass-Losar-Kaza route. The distance from Manali to Kaza is 183 km, and it takes about 5-6 hours (at one go) to reach Kaza. Manali-Kaza is a shorter route than the Shimla-Kaza route.
Though the Atal Tunnel has hardly reduced the road distance between Manali and Spiti valley by nearly 20km, the drive time between the two places has now been reduced by over 2 hours.
Manali town is one of the two — the second is Shimla — places to start the Spiti valley circuit tour.
Is it possible to drive to Spiti valley from Manali in winter (via Atal tunnel)?
No. Not until BRO (Border Road Organisation) punches another hole under Kunzum-La — a pass that keeps Spiti valley closed to vehicular traffic from November to May from Manali’s side.
What precautions do you need to take while driving through the Atal (Rohtang) tunnel?
If you are coming from any city located on the plains (like from Delhi/Chandigarh), do take a break in Manali — or a place located at a similar altitude.
Driving straight from a place located at 200m altitude to a place at 3000m can take a toll on your body. Moreover, the temperature difference between the two places is enormous — from temperatures above 40 degrees celsius to subzero temperatures at the north portal of the Atal tunnel (during winters).
The second thing you need to consider is the speed limit. As the Atal tunnel is built under the Seri Nallah stream. Water ingressing into the tunnel walls from Seri Nallah could cause the formation of black ice on tunnel tarmac during the winters as the tunnel will act as a venturi for icy winds blowing in through the North portal.
If you drive above the speed limits on a slippery surface, your car can easily go into a slide causing a major accident!