Bad traffic likely, flyover or not
Flyover or no flyover, Wellingtonians will still find themselves getting stuck in traffic queues at the Basin Reserve, critics of the project say.
But a little congestion may not be such as bad thing, as retired transport planner John Foster pointed out at the flyover's board of inquiry hearing in Wellington this morning.
Mr Foster, appearing for flyover opposition group Save the Basin, said the NZ Transport Agency's prediction that the flyover would handle Wellington's predicted upsurge in traffic for decades to come could not be relied on.
The reason being, no one really knew what would happen once the Mt Victoria and Terrace tunnels were duplicated, allowing twice as much traffic into the central city.
At present, the two existing tunnels acted as plugs on either side of the CBD. Because both were clogged to capacity, the number of cars entering Wellington could not get any bigger.
Until 2009, when the Government announced the duplicate tunnels as part of its roads of national significance programme, no thought had been given to removing the plugs, Mr Foster said.
As a result, transport planners on the Wellington city and regional councils had never planned for that scenario and were now scrambling to work out what would happen to the CBD in 2031, when both new tunnels were operating.
"We don't have a model that will satisfactorily predict what will happen when we do so," Mr Foster said.
When asked whether he thought the two-lane flyover would be able to handle the increased amount of traffic coming out of the Mt Victoria tunnel in 2031, Mr Foster suspected it would not.
Traffic would go from the flyover into the Buckle St underpass, which was planned to be three lanes wide, but probably needed to be four lanes, he said.
"It will simply mean the queue from [the] Taranaki St [intersection] will go back along the bridge."
If the roundabout was to be widened instead, the traffic queues would instead be at the Paterson St intersection where traffic exiting the Mt Victoria Tunnel hits the Basin.
"You get the same delay but in two different places."
Mr Foster said congestion should not necessarily be viewed as a bad thing.
Transport planners often used bottlenecks to avoid an area being flooded with traffic, such as they way the two tunnels currently kept Wellington's CBD in check, he said.
A four member board of inquiry is deciding whether the transport agency's application to build a two-lane highway flyover, 20 metres north of the Basin Reserve, should get resource consent.
The two-month hearing is now into its sixth week.
The Dominion Post