Option One: Esmonde to Britomart

This option explores a possible tunnel or bridge between Esmonde* on the North Shore and Britomart Transport Centre in the CBD. This is a public transport only option.

With this option public transport would solely use the new connection and would be a possible modal mix between rail and bus. The Northern Busway can easily be converted into rail to allow the rail in the tunnel to connect to the North Shore. Possible connections for public transport access would be made at Onewa and Wynyard Wharf.

General Traffic would still use the existing Auckland Harbour Bridge in an unchanged layout, with the southbound AM peak bus priority/Shelly Beach Road lane being removed. Walking and cycling would be made available on the existing Harbour Bridge to improve multi modal access between the North Shore and Auckland.

Positives: Complete public transport corridor where there is no interference from private transport. Walking and cycling available on the existing bridge. Direct connection from the North Shore to Britomart. Acts as a deterrent to private car use by providing more direct and easier Public Transport options. Currently this is the best option for long term car deterrents and the impacts of higher petrol prices and peak oil.

Negatives: No changes to layouts or alleviation of congestion for private transport users. Still sends bulk of traffic through the back of the city. Tunnels under Wynyard Wharf, an area undergoing development.

Not chosen because a single mode usage crossing would not benefit the region enough economically.

* These are general locations of the area, this does not mean specific locations such as Esmonde Road interchange. The study is identifying routes for protection.

Option 2: Esmonde to Britomart and the North Western Motorway (SH16)

This option is a variation of Option 1 and explores a possible tunnel or bridge between Esmonde* on the North Shore and Britomart Transport Centre in the CBD.

Public transport would have easy access to Britomart and would be a possible modal mix between rail and bus. The Northern Busway can easily be converted into rail to allow the rail in the tunnel to connect to the North Shore. Possible connections for public and private transport access would be made at Onewa* and public transport only at Wynyard Wharf.

General traffic would use the new crossing, but would only be able to access the North Western Motorway at Newton or the North Western and Port at Wellington Street. Public transport would connect, like in Option 1, at Britomart. Walking and cycling would be made available on the existing bridge. The existing bridge would still be open to general traffic.

Positives: Complete public transport corridor where there is no interference from private transport. Walking and cycling available on the existing bridge. Direct connection from the North Shore to Britomart. New connection to the North Western from the Northern. Alleviates some congestion from the existing Harbour Bridge. Offers a modal mix option including walking, cycling, bus, rail and private transport.

Negatives: It only offers connections for private transport to the North and West. Runs underneath the Wynyard Wharf, an area undergoing development.

This option does little to solve private transport congestion issues, with comparably low volumes of traffic making a western and northern connection, especially in the afternoon peak, has the possibility of making the connection under utilised. With the new North Western to Northern connections completed in 2006 as part of the CMJ project there is now little need to create another connection the North Western Motorway.

However with the Western Ring Route possibly being completed around the same time, the connection will make it easier to transition between the two creating a more attractive alternative. Comparing this with the previous proposal of a bridge between Northcote Point and Western Springs this created a closer connection for the North Shore to North Western for Western Ring Route access, this new connection however makes the alternative almost the same length as the existing making it redundant as a shorter or faster link.

This option was chosen, but modified.

* These are general locations of the area, this does not mean specific locations such as Esmonde Road interchange. The study is identifying routes for protection.

Option 3: Esmonde to Britomart and Grafton Gully (SH16)

This option explores the possibility of a tunnel from Esmonde* to Grafton Gully with access to Britomart for public transport and connections to the North Western motorway and Southern motorway at Grafton Gully.

Public transport would have improved access to Britomart and would be a possible modal mix between rail and bus. The Northern Busway can easily be converted into rail to allow the rail in the tunnel to connect to the North Shore. Possible connections for public and private transport access would be made at Onewa*.

General traffic would still use the existing Harbour Bridge and walking and cycling would be made available there.

Positives: Makes a true alternative to the Harbour Bridge for existing commuter traffic, as it offers connections between all three motorways and access to the CBD. Offers a modal mix option including walking, cycling, bus, rail and private transport. Provides western CBD access to Northern Motorway commuters. Stays away from the Wynyard Wharf developments. Keeps southbound traffic away from the CBD.

Negatives: Due to tunnel only it has a costly construction process. 30m high ventilation stacks, added cost of tunnel safety measures and surveillance. Less direct connection for public transport. Does not deter private transport.

This option has benefits of providing the easy North to North-West and South connection but was around $1bn more expensive that the chosen option. It also required extensive demolition around Beach Road.

* These are general locations of the area, this does not mean specific locations such as Esmonde Road interchange. The study is identifying routes for protection.

Bridge Option

This option, is a bridge 500m west of the current AHB, that lies between Northcote Point on the North Shore and Point Erin in Auckland City. This option also requires two tunnels one on each side of the Waitemata Harbour. The tunnel on the Auckland City side would be over 2km long and the North Shore tunnel around 300m long. The northern end connects to the Northern Motorway, like the AHB does, but the Southern end goes underneath Ponsonby and connects to the North Western Motorway at Western Springs.

Positives: This bridge option has the least effect on current motorway layouts, and out of all bridge options creates the least disruption to the current AHB during construction. There is a chance to build a well designed bridge that can become another icon for Auckland. It offers greater flexibility to lane layouts, designs and construction methods. And a closer connection to the Western Ring Route.

Negatives: It only offers connections to the North and West, there is no advantage to public transport especially rail due to its termination point, there are two tunnels plus a bridge, one being over 2km long that is bored underneath Ponsonby, high costs with little benefits and an inconvenient alternative during clip-on reconstruction.

This bridge option does little to solve traffic issues, with low volumes of traffic making a west to north connection, especially in the afternoon peak, has the possibility of making the bridge under utilised and not solving current issues. With the new North Western to Northern connections completed in 2006 as part of the CMJ project there is now little need to create another connection the North Western Motorway. However with the Western Ring Route possibly being completed around the same time, the South Western Motorway connections will make it easier to transition between the two creating a more attractive alternative. The fact that there are two tunnels and a bridge make the option redundant compared to a tunnel only option especially considering cost and benefits. Although some favoured this option, and it was cheaper, it did not meet urban design requirements. It was also very disruptive to Northcote and St Mary's Bay.

Artists Impression © Transit NZ

Tunnel Option

This option, is an immersed tube tunnel east of the current AHB, and lies between Toll Plaza on the North Shore and Wynyard Wharf in Auckland City. This option also requires two cut and cover tunnels to connect in the city. The northern end connects to the Northern Motorway, like the AHB does, but the Southern end mainly offers direct connections to the CBD and to the North Western Motorway. This option also has better options for public transport especially rail connections to Britomart. This tunnel option is the preferred option out of all bridge and tunnel proposals.

Positives: A direct connection to the CBD, leaving the existing AHB for straight ahead Southern Motorway trips. Easier options for Public Transport, easier connectivity to existing infrastructure especially the CBD arterials, proposed Victoria Viaduct and the Southern and North Western motorways. Less impact on surrounding areas, city opening travels through an underdeveloped area, no disruption to Northcote Point. Hassle free alternative during clip-on construction.

Negatives: Costly construction process, property purchasing, 30m high ventilation stacks, added cost of tunnel safety measures and surveillance, same end points as the current bridge, no change in access to the Western Ring Route.

The tunnel option will relieve significant pressure on the current AHB, due to a direct city connection, compared with the Bridge options terminating at Western Springs. The tunnel option makes rail more likely to be included in the crossing options due to easy links to Britomart. The Busway will also have the option to be on the existing AHB due to traffic relief by creating lanes. The tunnel option also gives access to the Southern Motorway for emergency purposes and when the AHB has to be closed for maintenance and the clip-on replacement period. This option does not offer easier connections to the Western Ring Route or the North Western Motorway than what is presently available.

This option gives greater flexibility than every other option, such as; being able to easily link in with the new Victoria Park southbound tunnel, easily connect with future rail networks to the North Shore, easy alternative during the clip-on construction, connects to CMJ (Spaghetti Junction) and has little effect on surrounding areas.

This is the most expensive option.

The tunnel option has been chosen, but modified.

Transit explored other options and was discussed in their Feasibility Study. You can see it here. (PDF).

For the three options displayed at the top:

83% of voters thought that option three was the best option, a tunnel from Esmonde Road to Grafton Gully. Mainly because this option on the surface made sense, when traffic modeling and integration with existing and future services was looked at the option didn't work as well, it was also $1bn to $2bn more expensive than the chosen option. The least chosen option was the public transport only tunnel.

For the tunnel/bridge options displayed at the bottom.

Overwhelmingly most people believed that tunnel option was the best option. Some die hard fans of the bridge option made their voices heard, but overall the tunnel option was preferred.