Second Harbour Crossing

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The currently favoured tunnel options would cross over the Waitemata from the western edge of the Western Reclamation (lower left) to the east of the Auckland Harbour Bridge on the Northcote side.^[1]

Second Harbour Crossing is the name given to the proposed second transport link over the Waitemata Harbour in Auckland, New Zealand. The second link would supplement the Auckland Harbour Bridge which is nearly at capacity and also provide more redundancy and added public transport linkages between Auckland City and North Shore City.

Discussed since shortly after the Auckland Harbour Bridge was first built (and quickly reached capacity before being widened), the proposed crossing has by now (2008) been narrowed down from around 160 alignment options to a multi-tunnel link somewhat east of the existing bridge. However no funding has been approved so far, and the project is estimated to be a decade or more away even if it should be approved and fast-tracked.

[edit] Background

Even with the clip-on section and the traffic management in place, the Harbour Bridge is experiencing severe congestion during rush hours, which will only get worse as North Shore City grows and Auckland City becomes more densely settled. Therefore, there is growing pressure for another harbour crossing. Many have also noted that such reliance on a single asset (which might experience failure via an earthquake or other disaster) is not in the interests of either Auckland or New Zealand.^{[citation needed]}

However, a 2007 study by the Auckland Regional Council has shown that peak hour traffic volumes are actually down compared to early 1990s. The morning peak (from 7 am - 9 am) has dipped from 17,048 vehicles inbound (towards Auckland City) in 1991 to 16,032 vehicles in 2006 (though the opposing traffic did climb from 5,872 to 10,555 vehicles). At the same time, the afternoon peak (from 4 pm - 6 pm) has fallen from 17,092 vehicles outbound to 16,759 (though again, the opposing traffic rose substantially, from 6,944 to 10,991). This is generally attributed to travel demand management and to drivers avoiding peak hours, and has raised some doubts about whether a second crossing is actually necessary.^[2]

Several projects either side of the bridge are also currently (2007) underway or planned to ensure that the motorway capacity on both sides matches that of the peak time capacity of the bridge (a factor which is considered by some to be more of a bottleneck than the bridge capacity itself),^[2] and to enhance the attractiveness of public transport. These include the upgrade to the Central Motorway Junction, the Harbour Bridge to City Tunnel (Victoria Park Tunnel) (which will increase capacity between the Central Motorway Junction and the bridge by 50%)^{[citation needed]} and the Northern Busway (which will provide a bypass parallel to the Northern motorway as it approaches the bridge). The future timing of an additional harbour crossing may also be delayed by the completion of the Western Ring Road (a combination of upgraded and new motorway skirting the western edge of the harbour and suburbs), which will provide some relief for traffic travelling between the North Shore City and West Auckland. This route is expected to be completed by 2020 at the latest.^{[citation needed]}

At the moment, official political statements still conclude a second harbour crossing is to be delayed (though it should be noted that the District Plan is a document updated only once or twice every decade):

The [Auckland City] Council will work with Transit New Zealand, the ARC, and the North Shore City Council to develop and implement measures, designed to optimise the future use of the existing Harbour Bridge and its approaches, for the peak period movement of people. This is to avoid or substantially delay the need to construct a second crossing of the Waitemata Harbour.^[3]

However, the current (2007) discussions about future traffic plans in Auckland, as well as for the Western Reclamation (an area where a proposed crossing alignment was to be anchored) have put the plans for a second crossing back into public discussion, though most of the plans would still envisage the actual construction to be one or two decades away.

[edit] Discussions

[edit] Alignment studies

Several solutions have been proposed in the past, including building another bridge alongside the existing one, a tunnel, or combinations of both. Following a detailed scoping study undertaken in 1996, Transit New Zealand identified its preferred options for a new crossing - either a new bridge approximately 500 m west of the bridge connecting to the North-Western Motorway (SH16) via a tunnel underneath Ponsonby and Grey Lynn, or a tunnel slightly to the east of the bridge connecting to the Central Motorway Junction via twin cut-and-cover tunnels under the western CBD / Victoria Park.^[4]

In 2006, Transit New Zealand noted that its 10-year plan, at that time being consulted on, would include funding for another study into a second harbour crossing.^[5] This study was declared to include the possibility of landing a future tunnel underneath the Tank Farm, with a connecting tunnel to south of Victoria Park. Costs are estimated at NZ$ 3 billion.^[6] Some commentators like Brian Rudman have noted that it would make the most sense to keep the new crossing for public transport only, possibly to connect with a rail tunnel to Britomart Transport Centre.^[7] This statement was largely supported by North Shore City mayor George Wood, who noted that public transport provision on the new crossing (including the possibility for light rail or heavy rail to connect to Britomart) had been part of North Shore City Council's plans for many years.^[8]

A possible tunnel between Mechanics Bay and Northcote was also be considered in the feasibility studies, but was faced increasing criticism from local groups, as well as problems due to the denser residential zones and geographic difficulties faced on such an alignment.^[9]

In December 2007, Transit New Zealand noted that the more than 160 options had been narrowed down to only two alignments. The first possible alignment (of approximately 4.5 km length) would be a parallel link several hundred meters directly to the east of the existing bridge (either as a bridge or a tunnel), while the second alignment (of approximately 6.5 km length) would start in the same general environs in North Shore City, but travel diagonally southeastwards to link up with the motorway at Grafton Gully, east of the Auckland CBD. The seond option, due to the need to cross shipping lanes, would need to be a tunnel. It could also possibly be connected to the CBD via a side branch tunnel (for use by public transport only).^[10] North Shore City has noted that it would prefer a tunnel option for aesthetic reasons, and to potentially emplace light rail within the tunnel at a future stage.^[11]

[edit] Bridge alternative

During the public discussions in 2007, an interest group also put forward a proposal to build a new, much larger bridge to the east of the existing structure, and demolish the old Harbour Bridge. They argue that the new bridge, which would be about 50% longer than the existing one, could be constructed to provide for dedicated public transport (including light rail, which is credited with allowing a tripling of the total capacity in people moved over the existing Harbour Bridge), as well as for cyclists and pedestrians. Significantly, they argue that the new bridge would more or less pay for itself, by freeing up new residential land (currently taken up by several km of motorway approaches) in some of the most sought-after Auckland locations like Saint Marys Bay. The proponents claim that the bridge would put more than 35 hectares and open up 3.3 km of shoreline, a prize which would more than make up for the fact that the plans for the Western Reclamation redevelopment would in this case find themselves partly compromised by a major motorway in its area. The new bridge would also be cheaper to operate and would not need emission vents like a tunnel.^[12][13]

The new bridge design, a cantilever spar cable-stayed bridge, was proposed by the Jasmax architectural firm, which note the 'Anzac Centenary Bridge' would be buildable in time for the 100-year memorial of the Gallipoli landings in 1915.^[12]

[edit] Recommended Option

In mid-2008, the Waitemata Harbour Crossing study group released their recommended option (2C), which would connect from the existing Esmonde and Onewa motorway interchanges on the North Shore City side to Auckland City, reaching land in the southwestern part of the Western Reclamation (though the links may continue as tunnels for some further distance, likely going under Victoria Park). The option selected from several hundred considered alignments foresees four separate tunnels, two for motor vehicles and two for public transport.^[1] Due to the reduced costs of narrow-diameter tunnels driven by modern tunneling methods compared to providing similar capacity in one or more large tunnels, this option was considered the most economic.^{[citation needed]} The characteristics of the recommended options are:^[1]

• two motorway tunnels (three lanes northbound in one tunnel, three lanes southbound in the other), carrying State Highway 1
• two public transport tunnels (rail in the recommended option), connecting Britomart with a new North Shore City rail system
• demolition of the Victoria Park Viaduct and deemphasising of the Auckland Harbour Bridge for some through routes
• provision of a new rail station for the future Wynyard Quarter at the southern edge of the new development
• an estimated cost of NZ$3.7 to NZ$4.1 billion, though the links could be built in stages, reducing direct costs

The study also assumes that by 2041, the volume of trips over the harbour will increase by 80% from current (2000s) levels, and estimate that the public transport share on the link would rise from a current 15% to then 30%.^[1]

[edit] Other modes

Some have commented that with the construction of the new motorway links via the second crossing, capacity on the existing bridge could be freed up for walking and cycling links. However, advocacy groups have noted that any second crossing would not be built for possibly decades to come, if at all, and thus should not detract from providing the links sooner.

[edit] See also

General

• Public transport in Auckland
• Transport in Auckland

Specific

• Central Motorway Junction, the major motorway junction connecting southeast of the bridge
• Newmarket Viaduct, similarly important traffic bottleneck on other side of Auckland CBD
• Western Reclamation, large industrial area east of the bridge, possible site of 2nd crossing

[edit] References