Central Motorway Junction

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Spaghetti Junction photomanipulated image (mostly shown as eventually realized).

Southern section of the new CMJ from the Upper Queen Street bridge.

Looking south on the northern end of the CMJ.

The Central Motorway Junction or CMJ, best known as Spaghetti Junction, is the intersection of New Zealand State Highways 1 and 16 south of the city centre of Auckland, New Zealand.

Over 50,000 people had to move from the area when the central motorway network was constructed in the 1960s and 1970s, with major effects on the nearby Karangahape Road shopping area. The junction was finally fully completed in December 2006. The picture to the right is a computer generated image showing the final form of these upgrade works.

The central motorway junction forms the intersection between the three major motorways of Auckland (Northern Motorway (1), Southern Motorway (1), and Northwest Motorway (16)), and provides access from these routes to the city centre. It is principally located in a series of gullies to the south and east of the CBD and in cuttings to the west.

It has somewhat of a hybrid function, falling somewhere between a typical ‘X’ interchange and ring road around the city centre. However all linkages are direct and there is no separate ring road as such. The interchange and associated structures encircles the Auckland CBD on three sides, the waterfront to the north forming the fourth side of the commonly used ‘border’ of central Auckland.

[edit] Connections

The Central Motorway junction provides direct motorway-to-motorway links between the following four routes radiating from the city centre:

Northern Motorway (SH1) to/from North Shore City via Auckland Harbour Bridge
Southern Motorway (SH1) to/from Manukau City and
Northwest Motorway westbound (SH16) to/from Waitakere City
Northwest Motorway eastbound (SH16) to/from Ports of Auckland and eastern suburbs

The last of these links (Northwest Motorway eastbound to Northern Motorway northbound) officially opened on December 19, 2006, marking the full completion of the junction.

In addition, the CMJ also includes the primary dedicated city exits from SH1 and SH16 to downtown, Grafton Gully (the section of the Northwest Motorway between the Upper Queen Street bridge and The Strand in Parnell, and the Southern Motorway between Symonds Street exit and The Strand), and some five other pairs of ramps giving access to the central area.

An interesting structure of note is the cutting underneath Karangahape Rd, where some 19 lanes of traffic forming 9 distinct links pass through a very constrained cutting under the Karangahape ridge on a two level structure (The area visible in the centre-left of the image above).

The other two major motorways under construction in Auckland, the ‘South-Western’ and ‘Upper Harbour’ motorways will form a continuous link in the west of the city between SH1 in the south at Manukau with SH1 in the north at Albany. The main goal of this route is to provide an alternative north-south route in the west that bypasses the central area and avoids the often congested central motorway junction.