The peak travel season is during May and June, when tourists visit Rohtang Pass. Most domestic tourists return to Manali and do not cross north of the pass. The Himachal Road Transport Corporation (HRTC) and the Himachal Pradesh Tourism Development Corporation (HPTDC) both operate buses that travel the entire highway in two days. Buses start from Manali north at 4 am and after every two hours or so until 12 noon. The time to Keylong is 4 to 10 hours depending upon the condition of the road. Traffic jams may occur at Beas Nallah near Marhi and again at Rohtang Pass. It is advisable to cross Rohtang Pass before 8 am.