The highway leaves SH 1 at Waipara, some 60 kilometres north of Christchurch, and initially heads north, crossing several rivers and skirting the Balmoral State Forest. After crossing the Hurunui River there is a 13.7 km straight, the longest straight section of highway in New Zealand.NZ Transport Agency FAQs Just north of Culverden, it reaches the valley of the Waiau River and turns west to the course of this river and its tributary the Lewis River up the valley to the 907-metre Lewis Pass, the northernmost of the three main road passes across the Southern Alps.
