All On or Off Ramps connecting the highway are grouped and referenced to a unique interchange number. Ramps are generally numbered in a clockwise direction around the interchange, based on the location of the start of the ramp. The example (image) indicates that the centre of the interchange lies on SH 1, approximately 5 km past RS 262, hence the number given is 267.
Used in conjunction with Reference Station Signs (LR-RS), Established Route Positions (LR-ERP) and Kilometre Marker Posts (LR-KMP). Please refer to the NZTA Location Referencing Management System (LRMS) Manual for more information.