[5] It was generally assumed that below-ground construction would be required where AR3 passed through Avondale Heights, to a maximum depth of 41 m. On the basis of technical and environmental assessments, the AR3 and AW4 route options were dismissed.

[14] The board called for a report from officials on managing fumes from the tunnel "to benchmark the proposed approach incorporated in the design work to date against current international best practice".

In response to submissions questioning the adequacy of just two traffic lanes running in each direction, it sought a comparative assessment of the operational performance and costs of providing three-lane tunnels, initially estimated at $2.14 billion.

[16] It was announced on 26 August 2008 that the steering group had advised the Government that a public-private partnership (PPP) - which would require a $2 toll per trip - was the best way of building the new $2 billion section of the city's Western Ring Route.

[17] In October 2008 the NZ Transport Agency released report findings which showed that tunnel emissions would have a negligible effect on local air quality.

[18] These findings were disputed by Waterview Primary School representatives, who claimed that the report hadn't taken into account the impact of tolling "which could add more traffic to surface roads", hadn't given sufficient consideration to "international best practice on air filtering", and had failed to account for "ventilation fans being turned off during off-peak times, allowing emissions to escape through the tunnel openings".

[20] The Auckland Regional Council requested NZTA to reconsider whether the proposed Waterview Connection was the most cost-effective way of completing the Western Ring Road, with a reconsideration of the costs and benefits of the alternative Rosebank route.

Because he was "not comfortable" with the idea of reducing the tunnels to two lanes with no ability to enlarge them for future traffic demand, he gave officials until April to review all options for a connection of State Highway 20 to the Northwestern Motorway at Waterview, including a potentially disruptive surface route through Mount Albert and previously discarded "cut and cover" proposals.

He was unable to predict a completion date for Auckland's 42 km western ring route, saying officials regarded a 2015 target of the previous Labour government as "aspirational".

The decision to fast-track was cited as necessary to avoid approval delays which had held up other projects for over 15 years, though local groups were pessimistic about their chance to achieve fair mitigation within the tight process.

Also included in the fast-tracked project was the decision to undertake significant capacity-related widening works on State Highway 16, which are outside of the Waterview area (from St Lukes Road interchange to beyond Te Atatū), which were bundled into the application process which consists of 54 resource consents and 7 designations.

[38] With around 40 folders of materials and plans to go through, local community groups expressed anger in October 2010 that they would have only four weeks to formulate submissions regarding the fast-tracked applications.

Calls by Auckland City Council and an affected community board to extend the deadline were rejected on the grounds of the tight statutory timeframe.

On 3 September 2010, NZTA's application for designation and resource consents for the Waterview Connection section of the Western Ring Route 'road of national significance project' was referred to a Board of Inquiry.

One of them was the shape and locations of the two proposed ventilation shaft buildings near the northern and southern tunnel entries, and their likely effect on local visual amenity (with the shafts, at 25m-27m height, proposed to tower visibly over surrounding suburban areas) and local air pollution levels (where an independent report considered that the NZTA had been too optimistic in terms of pollution conditions during traffic jams and due to induced demand).

[1][4][39] In March 2010, NZTA announced that $10 million enabling works would start at the southeastern end of the route, diverting a sewer line and a tributary of Oakley Creek in preparation for the new Maioro St interchange.

While the works would occur on land already designated as motorway, local groups were concerned that the move preempted the consenting process for the main alignment, which still was to happen at that stage.

[49] The consortium also included McConnell Dowell Obayashi Corporation, PB New Zealand, Beca Infrastructure and Tonkin + Taylor, as well as five sub-alliance partners and contractors: SICE, Wilson Tunnelling, Downer EDI Works, Boffa Miskell and Warren and Mahoney.

[56] A number of not directly motorway-related projects will form part of the SH20 connection works, either to mitigate negative effects on the environment, or to provide for other transport modes.

NZTA has proposed replacement passive open space below & around the Waterview interchange ramps, and the existing privately owned empty site adjoining Alan Wood Park and future surface motorway.

[64] Auckland Transport designed the 2.5 km long "Waterview Shared Path" from Alan Wood reserve, with construction happening from March 2016[65] to mid-2017.