Auckland Northern Motorway

The Northern Motorway starts near Puhoi, in the former Rodney District, at the southern end of the Puhoi-Warkworth Motorway, which opened in 2023.

The initial 7 km section is an automated-toll road, also known as the Northern Gateway Toll Road. It begins by traveling under Johnstone's Hill though 340-metre long twin tunnels. The electronic toll-registering gantry is at the southern end. At the first junction, west of Orewa, the motorway becomes toll free.

The next 17 km to Albany runs through a mainly rural environment. An interchange at Silverdale provides access to the Hibiscus Coast and the Whangaparaoa Peninsula, and access to the alternative toll-free route north via Urban Route 31 (formerly State Highway 17). The Orewa interchange can also be used, but requires driving through local residential areas. South of the junction at Dairy Flat is the motorway's only service centre, which serves northbound traffic, and is the toll cash-payment point for northbound traffic.

The motorway then descends steeply into the northern suburbs of the former North Shore City, the northern of Auckland's four former cities. Crawler lanes are provided for heavy vehicles between Oteha Valley Road and Greville Road. The Greville Road interchange was until 1999 the northern terminus, with the current northbound entrance and exit ramps following the old formation down to the roundabout intersection with Albany Highway.

The motorway proceeds south-east through the suburbs of the North Shore, with interchanges at Upper Harbour Highway, Tristram Avenue, Northcote Road and Esmonde Road allowing access to the suburbs. The Upper Harbour Highway interchange is the northern terminus of the Western Ring Route, which provides an alternative north–south motorway route around Auckland.

At Esmonde Road, the motorway turns south-west to follow the northern shore of the Waitematā Harbour to Northcote Point, where it crosses the Auckland Harbour Bridge. The bridge has a contraflow system on it which allows five lanes southbound and three northbound during morning rush hour, five lanes northbound and three southbound during evening rush hour, and four lanes each way at other times. The lanes are separated by a moveable median barrier.

Coming off the bridge, the road turns sharply to head eastwards towards the Auckland city centre. An interchange with Fanshawe Street allows access to the northern end of the city centre, and also allows lanes to be dropped ahead of the narrow four-lane Victoria Park Viaduct. The motorway then turns south-east across the Victoria Park Viaduct, and travels down the western side of the city centre, with an exit at Cook Street for the southern end of the city centre.

The motorway emerges at the top of the Central Motorway Junction ("Spaghetti Junction") and terminates at the Northwestern Motorway, becoming the Southern Motorway.

The Northern Motorway between the Auckland Harbour Bridge and the then Fanshawe Street terminus in May 1960. Photo by Denis Wilford.

The first section of the Northern Motorway opened on 30 May 1959, in conjunction with the opening of the Auckland Harbour Bridge. The motorway totalled 7.4 km, from Northcote Road to Fanshawe Street. On its opening day, 51,000 vehicles crossed the Harbour Bridge, with southbound traffic backing up for 10 km north of the toll plaza (near the present Stafford Road exit) with vehicles wishing to cross the bridge for the first time.[5] Initially, the Auckland Harbour Bridge Authority owned and operated the motorway between Fanshawe Street and the toll plaza, while the National Roads Board (the predecessor to the New Zealand Transport Agency) operated the remainder of the motorway from the toll plaza to Northcote Road. During the motorway's construction and widening, large sections of Smiths Bush, a remnant kahikatea and taraire forest, were destroyed.[6]

Access to the bridge was at first motorway limited, with all ramps facing towards the Harbour Bridge. Tolls for the bridge were collected manually, with cars initially paying 2/6 (two shillings and sixpence) to cross the bridge (equivalent to about $5.50 in 2017 dollars).[7]

In 1962, the Victoria Park Viaduct opened, and the motorway was extended south from Fanshawe Street, over the viaduct, to Cook Street/Wellington Street. In 1969, the motorway was extended northwards from Northcote Road to Tristram Avenue, and the Auckland Harbour Bridge's clip-on lanes opened, widening the bridge from four lanes to eight lanes.

In 1978, the motorway was extended south to meet the Southern Motorway at Nelson Street/Hobson Street. This allowed motorway traffic a clear run from Tristram Avenue to St Stephens, on the northern side of the Bombay Hills.

In 1979, the Northern Motorway was extended northward to Sunset Road, near the present Upper Harbour Highway interchange. The motorway ended at a set of traffic lights on the top of a hill, giving limited visibility to motorway traffic. In 1984 a two-lane expressway opened, continuing from Sunset Road to Greville Road and on towards Albany Highway Albany Village. On 30 March 1984, the last tolls were collected for the Harbour Bridge, making the entire Northern Motorway free of charge from 31 March 1984.[8]

In the 1980s, tidal flow was introduced on the Auckland Harbour Bridge to assist with peak flows on the Northern Motorway between the North Shore and central Auckland. The two central lanes were made reversible to allow a 5+3 split favouring the peak direction (southbound in the morning, northbound in the evening) during peak hours, and 4+4 off-peak. The lanes were controlled by overhead signals, which some motorists on the Motorway ignored and were killed when they collided head-on with oncoming traffic - between 1 January 1989 and 27 November 1989, five people died as a result of collisions involving the so-called "suicide lanes".[9] In 1990, a moveable barrier was installed to separate the traffic flows.

The expressway between Sunset Road and Greville Road was upgraded and became a part of the Northern Motorway in 1994. A new interchange was created at Upper Harbour Highway and Constellation Drive to replace the Sunset Road intersection.[8]

The late 1990s saw the construction of the first stages of the Albany to Puhoi Realignment (ALPURT) – a 27 km extension of the Northern Motorway, bypassing Albany Hill and the Hibiscus Coast. The first section, ALPURT A, opened between Greville Road and Silverdale on 20 December 1999. At 13 km in length, it was the longest section of motorway to open at once in New Zealand. At the same time, ALPURT B1, a two-lane expressway between Silverdale and the back of Orewa opened.[8]

In 2006, an upgrade to the Central Motorway Junction saw ramps open between the Northern Motorway and the Northwestern Motorway, and the Northern Motorway and Grafton Gully. Beforehand, traffic travelling from the Northern Motorway to the Northwestern Motorway or Grafton Gully had to exit at Cook Street and travel through local city streets to connect to West Auckland or the Port of Auckland.

ALPURT B2, the Northern Gateway Toll Road, opened on 25 January 2009 between Orewa and Puhoi. The Northern Gateway Toll Road was the first automated toll road in New Zealand, and the first under the authority of the NZ Transport Agency. At the same time, ALPURT B1 was upgraded to motorway standard to complete the Northern Motorway from central Auckland to Puhoi.[8]

The Victoria Park Tunnel project was completed in early 2012 having been opened earlier in the year. Three northbound lanes were constructed in a cut-and-cover tunnel next to the existing four-lane viaduct. The viaduct, previously two lanes in each direction, was reconfigured to two pairs of southbound lanes; one pair accessing the Cook Street off-ramp and Port and Northwestern Motorway connections, the other connecting to the Southern Motorway. In addition to the tunnel a movable median barrier on the northbound section between the tunnel and the Harbour Bridge allows five northbound lanes to be used in peak traffic times. The southbound section was also widened to five lanes, this being permanent.[10]

A 34 km four-lane motorway or expressway from the current terminus of the Northern Motorway at Puhoi to north to Wellsford was one of the seven "Roads of National Significance" announced in March 2009.[11] The contract for the section from Puhoi to Warkworth was awarded in November 2016 under a public-private partnership[12] and was opened in June 2023.[13]

The Northern Motorway northbound lanes, just south of the Esmonde Road interchange.

Territorial authority and local board(s)[19]	Location	km[20]	#	Destinations	Notes
Auckland — Rodney Board	Puhoi			SH 1 north — Warkworth, Whangarei	Northern Motorway begins Northern Gateway Toll Road begins
	386		Puhoi Road — Puhoi	Northbound exit and southbound entrance
			Johnston's Hill Tunnels	340m long
Auckland — Rodney/Hibiscus and Bays Boards	Orewa		394	Grand Drive — Orewa	Northern Gateway Toll Road ends
	Millwater		396	Wainui Road/Millwater Parkway — Millwater	Northbound exit and southbound entrance; opened May 2015[21]
	Silverdale	398.0	398	Route 31 Hibiscus Coast Highway — Silverdale	Toll-free route north Formerly SH 17 36°37′31″S 174°39′46″E
	Dairy Flat	401.9		Dairy Flat Service Centre	Northbound only 36°39′34″S 174°40′03″E
Auckland — Upper Harbour Board	Albany North	409.9	410	Route 29 Oteha Valley Road — North Harbour Stadium, Albany
	Rosedale	411.8	412	Route 25 Greville Road/Albany Expressway — Browns Bay, Massey University, Albany	Formerly SH 17 36°44′09″S 174°43′05″E
	Meadowood	414.0	413	SH 18 (Upper Harbour Highway) — Greenhithe, Waitakere	Southbound exit and northbound entrance[22]
			414	Constellation Drive — Mairangi Bay	36°45′03″S 174°43′34″E
Auckland — Kaipatiki/Devonport-Takapuna Ward	Forrest Hill	416.8	417	Route 21 Tristram Ave — Wairau Park, Wairau Valley, Glenfield, Forrest Hill
	Northcote	418.8	419	Northcote Road — Northcote, North Shore Hospital, Milford
	Akoranga	420.3	420	Route 26 Esmonde Road — Takapuna, Devonport, AUT
Auckland — Kaipatiki Board	Northcote	422.0	421	Route 27 Onewa Road — Northcote, Birkenhead
		422.9	422	Stafford Road	Northbound exit only
	Northcote Point	423.2		Auckland Harbour Bridge over Waitematā Harbour	36°49′50″S 174°44′26″E
Auckland — Waitemata Board
	St Mary's Bay	425.0	423	Shelly Beach Road — Ponsonby, Herne Bay	Southbound exit and northbound entrance
	Auckland CBD	426.2	424A	Route 6 Fanshawe Street — City Centre (North)	Southbound exit and northbound entrance
		426.6		Victoria Park Tunnel (northbound) Victoria Park Viaduct (southbound)	Tunnel is 440m long 36°50′49″S 174°45′11″E
		427.0	424B	Cook Street — City Centre (South)	Southbound exit and northbound entrance (via Wellington Street)
		427.2	424C	SH 16 east (Northwestern Motorway) — Port	Southbound exit and northbound entrance
			424D	SH 16 west (Northwestern Motorway) — Waitākere, Helensville	Southbound exit and northbound entrance
		427.0		SH 1 south (Southern Motorway) — Manukau, Hamilton	Northern Motorway ends

• ^ distance rounds down to 427 at the beginning of the Southern Motorway.

• List of motorways and expressways in New Zealand