Auckland Harbour Bridge closures costing millions, economist estimates

Millions of dollars are blowing in the wind - that is the cost of weather-related restrictions on Auckland's Harbour Bridge, according to an economist.

Gusty conditions on Monday meant the bridge was reduced to two lanes in each direction, and speed restrictions were in force.

Speed limits kick in when winds hit 90 kilometres an hour; when gusts reached 110kmh, the bridge could close all together.

In that situation, traffic has to take the long way around on the Western Ring Road via State Highway 16 and SH18.

Infometrics principal economist Brad Olsen told Checkpoint the bridge closures were a significant cost to people.

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"We estimated ... based on the amount of time the bridge has been closed over the last couple of years ... about 700 minutes ... some of that could cost in the vicinity of $2.1 million," he said.

"These detours, all of these wind issues do cause people real delays, real costs, real challenges."

Olsen said there were hidden costs and lost productivity, too.

"If the bridge is only closed for, say, five minutes in a day, how many people are gonna look at that, and go, 'Well, there's obviously a clear concern that I might not be able to get across the bridge. Do I actually risk it or do I take that detour?'," Olsen said.

"If you look at the total number of days where the bridge could have been closed, because there was a closure, the sort of behavioural response of people having to take the detour to not get caught out could cost them a vicinity of nearly $36 million."

Taking a significant detour not only cost time - it had a long-term impact on vehicles, too.

"It's the cost of having to take that detour because of the delayed time. It's also the running cost because you're having to go along the [detour] route; it's taking you longer.

"It's effectively more wear and tear on your vehicle. All up, you're talking around $2700 a minute, perhaps in delays."

Because bridge closures had become more prevalent, there had been a cost to the economy over time.

"But as we all know, it's very difficult to do anything about these challenges in a very quick manner, so we might not see wind-anomics go away anytime soon," he said.

The Auckland Harbour Bridge was facing more pressure as it aged.

"You're seeing more and more of these events, also the Auckland Harbour Bridge as it currently is constructed, was never meant to live in it for infinity.

"Over time you are seeing that those challenges are becoming greater, it's being put under more pressure. It's getting older."