Any changes to Wellington's Basin Reserve roundabout will need to wait until new road agreed on

Friday, 24 May 2019

An artist's impression of a new-look Basin Reserve area shows people mingling near a green space on what appears to be the space currently occupied by Cambridge Terrace, and a few cars travelling west on Sussex St - currently an eastbound road.

Solving the Basin Reserve conundrum is one of the key projects for transport planners hoping to get Wellington moving. But any improvements, even in the short-term, remain some time away. Damian George reports.

It's been over three years and there are still no concrete plans for how to unblock traffic at the Basin Reserve.

Any 'minor' changes to the State Highway 1 roundabout will need to wait until the final design for a new road separating state highway and local traffic is determined.

The Let's Get Wellington Moving group, formed in 2015 following the failed Basin flyover proposal, released its $6.4 billion plan to solve traffic congestion between the airport and Ngauranga Gorge last week.

But despite years of planning, the group was not prepared to say how it planned to eventually separate east-west traffic from north-south traffic at the State Highway 1 roundabout, other than to say there will 'definitely not be a flyover'.

A new road to separate local and state highway traffic at the Basin Reserve is at least 10 years away.

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The most likely location for a new road would be under Sussex St, on the western side of the ground, connecting to the Arras Tunnel.

Its short-term plans to free up traffic in the meantime - before a new road is constructed - were also left painfully vague, with the project's indicative timeline promising a start on 'Basin improvements' by 2024.

Programme director Barry Mein said on Friday those short-term improvements - changes to the road layout at ground level - ultimately hinged on the final design of the new road at the roundabout.

It's unclear what changes are possible to the road layout to help improve the roundabout in the meantime.

Wellington Mayor Justin Lester said that was likely to be a tunnel under Sussex St, on the western side of the ground, connecting to the Arras Tunnel.

But Mein said that was only a possible solution, and could not be confirmed until it was first determined how a proposed mass transit system navigated past the Basin.

'The extent of any minor works, and the degree of benefits that would come out of these, would largely depend on the eventual solution for grade separation at the Basin and how quickly that can be implemented.

'The minor works, therefore, need to be examined in more detail at the next stage of the programme, alongside more detailed investigation of grade separation.'

Preliminary work had been done to determine some of the potential fixes, but Mein did not want to comment on what those might look like.

Projected travel times on various routes by 2036, after the Let's Get Wellington Moving project is completed.

In announcing the programme on May 16, Lester said transport planners were looking at a 'really unique design solution' for the Basin, with a price tag of $190 million.

It was hoped construction would start on the new road before 2029.

'At the upper end of Sussex St, it's 8 metres above Kent and Cambridge Terrace. So in terms of the grade separation, we're going to run down the back of the hill and behind a building and come into Cambridge Tce.

'It's really straight forward - no need for a flyover.'

Wellington City councillor Chris Calvi-Freeman, a member of the Let's Get Wellington Moving governance group, said he had not been shown any designs or suggestions on how the road layout could be improved in the short-term.

'I'm not entirely sure what they've got planned. I'd be very interested to know.'

It was also unclear whether the new tunnel under Sussex St would be one-way or two-way, Calvi-Freeman said.

The initial proposal was for a two-way road, but that was based on the assumption the highway would be reconfigured into a tunnel under Te Aro.

The Government rejected that proposal, along with a second Terrace Tunnel, meaning planners would need to design 'some sort of a work around'.