Future Auck Motorway Plans Revealed
While the Waterview tunnel hearings continue, the authorities are getting the itch to build more motorways and develop further the Western Ring Route (WRR) along with other changes.
Here’s the latest thinking of what NZTA wants to do with the Auckland motorway network, this information obtained under the Official Information Act.
The NZTA thinks:
- Further investment in the Western Ring Route is required now to ensure the route performs fully in reducing congestion and improving the reliability of travel time
- Wants brought forward SH1 Hill to Takanini Southbound 3-laning
- Wants brought forward SH1 Constellation to Greville Rd Northbound 3- laning
- Wants done before rail electrification, SH1 Ellerslie -Panmire to Greenlane Northbound auxillary lane
- If approved this will result in the retiming of other projects over the next 10 years as “significant new or accelerated investment” will be needed
NZTA board papers say that while work on the Waterview project represents the completiion of the WRR as a continuous State Highway there remains 2 projects which require further development to achieve a route that both operates to motorway standard and provides optimal contiinuity and capacity in order to realse the full benefits of the route.
- SH1 Manukau to Papakura
- Upper Harbour Highway to Greville Rd
Says the board paper: “Presently these two projects are not in the 10 year SH plan nor are some other important works on WRR which will ultimately be needed to realise the full benefits of the WRR. This stems from previous policies which focused on a discrete project – by – project approach to the development of the SH network which was “significantly constrained” in terms of funding.
“Also a key objective was demand management which assumed ongoing capacity constraints would result in more balanced mode share. There are a number of examples of such legacy projects currently on the Auckland state highway now such as the Waterview Connection itself, SH16 Grafton Stage 3 and the Walmsley Road bottleneck at Manukau on SH20.
“The approach proposed for taking forward the completion of the State Highway network in Auckland is one of coherent programming of corridors of work in order to protect continuous appropriate functionality and a targeted level of service. Ths will be ultimately described in the updated SH Network Strategy under development which will include the results of current consultation on the proposed SH Classification.
“A completed SH network strategy will ensure the prioritisation of projects is fully aligned with the objective of the GPS. In the absence of the State Highway Network strategy and not recognising the change in emphasis towards a balanced transport network has left us with unprogrammed projects which have a fundamental part to play in developing the wider benefits of the WRR,” says the report.
The completion of SH20 Manukau extension project in August represented the final connection of the Southern link of the Western Ring Route with SH1.
The report says that presently the corridor doesn’t function as a motorway as it has been necessary to introduce mainline ramp metering into SH20 to restrict capacity to maintain network balance between vehicle demand on SH20 and SH1 southbound in the pm peak. The impact of SH1 of unconstrained demand on SH20 was seen on the network in August with pm peak delays on SH1 extending back 10km on Mt Wellington highway.
In order to bring “full functionality” to the network and optimise the WRR and SH1 in the south, it’s considered a further package of improvements i required to be brought forward to SH1 south of SH20 over the next 10 years.
- Stage 1: Hill Rd to Takinini southbound 3-laning ($40m-$80m) BCR 3:4
- Stage 2: SH20 to Hill Rd southbound 4-laning
- Stage 3: Takanini to Papakura 3-laning
- Stage 4: Takinini interchange upgrade
It’s believed the ramp metering could not be fully removed until completion of stages 3 or 4.
On completion of Waterview, State Highway 18 at Constellation Drive will be the final piece of the WRR which is considered not to expressway standard.
SH1 Constellation to Greville is located at the nexus of three RONS projects, the WRR, Vic tunnel and Puhoi to WEllsford.
The board report says there are presently significant capacity constraints in the SH18/SH1 corridors around Constellation and on completion of Hobsonville in 2011 this is anticipated to worsen as wider northbound capacity becomes enhanced.
The long term plan for the SH1/18 intersection has always been grade separated motorwats to motorway movements. The NZTA has completed a further review which has reinforced this approach and confirmed that a motorway to motorway configeration can be adopted which future proofs busway extensions north to Orewa and west towards Hobsonville. The busway extension northbound is “currently subject to further investigation by the NZTA.”
For this area, it is recommended:
- Stage 1: SH1 Constellation to Greville Rd 3- laning Northbound ($50m-$80m) BCR 3.3
- Stage 2: Sh18 upgrade to motorway standard and grade separation to Sh1 (north facing ramps only) and SH1 3-laning Southbound ($400m-$600m BCR 3.4)
- Stage 3: Greville Rd interchange upgrade ($75m-$150m BCR 4.6)
The report says there is currently significant congestion experienced on SH1 at Constellation in the pm peak period brought about by insufficient capacity on the Northern Motorway to accommodate the merge demands from Upper Harbour Highway at Constellation Drive / Western Ring Route.
The recently completed study examined northbound hard shoulder bus lanes between Constellation and Greville as a means to mitigating these issues and contributing further to the success of the busway.
The study found that this would be $27m with a BCR less than 1. Hence the study concluded that the general capacity increase with bus hard shoulders at a cost of $20m more and BCR of 3.3 was the preferred option.
In the background
Other significant projects under consideration and will form part of the Auckland Plan discussions:
- The next harbour crossing
- The East-West link “rung”
- SH16 Port upgrade
- SH2OA/B upgrades
Rail electrification impacts
Another project is the completion of the northbound auxilliary lane between the Ellerslie-Panmure Highway and Greenlane on SH1. Presently the existing lane is only provided for half of this seciton of the motorway due to the previous designation and rail alignment issues when the project was investigated and represents a significant bottleneck on this section of the SH.
In recent months, NZTA has been approached by KiwiRail to work collaboratively with them on delivering the remaining section ahead of rail electrification. This presents NZTA with a limited opportunity to provide for the upgrade of this section of the network ahead of rail electrification later this year after which the costs and design implications for both agencies will make it more compelx and costly.
A recent update of the project in light of the Kiwirail offer has indicated the the project would cost in the order of $15m-$20 to design and construct “but it has a significant BCR of 7.6.”