It forms the southern part of the ring road surrounding Tongariro National Park and provides access to the southern side of Mount Ruapehu and the Turoa skifield.

SH 49 continues southeast across rolling hills, running broadly in the same direction as the North Island Main Trunk.

It passes the rural villages of Rangataua and Karioi, before meeting the railway line at the Whangaehu River at Tangiwai.

The bridge here has flashing lights and gates to block off the road in case of a lahar from Mount Ruapehu's crater lake.

To the side of the bridge is the Tangiwai memorial, erected to remember the 151 people who died in the Tangiwai disaster when a Wellington to Auckland express train plunged into the river following a lahar on 24 December 1953.