Behind the scenes of Auckland's overnight motorway closures

It's 10pm at night and a carpark on Auckland's North Shore is buzzing with activity. A group of workers has gathered in their hard hats and high-vis vests ready to start their shift.

These are the people who keep Auckland's motorways safe - and they're working on closing the entire northbound section of State Highway 1.

People travelling across Auckland at night will be familiar with the overnight closures and the detours - but few understand what they're for and what really goes on behind the scenes. Newshub went along to one to see what's going on.

Andrea Williamson is the manager of Auckland System Management (ASM), an alliance between HEB Construction, Fulton Hogan and Waka Kotahi NZ Transport Agency (NZTA) to operate and maintain Auckland's motorway network. She's also the ASM alliance manager with NZTA. Basically, she leads the maintenance alliance for Auckland, managing around 260 people out day and night making sure everything is safe.

The length of motorway that needs to be maintained is huge - about 450km - and it requires regular inspections and "constant maintenance". 

"We maintain and operate the Auckland network right up north to the Puhoi Tunnels and south to State Highway 2 and along State Highway 2 to where you go to Tauranga," Williamson says.

"We've got people out there 24/7 looking at each of the assets, making sure everything is safe and making sure we're keeping everything maintained."

Andrea Williamson, Auckland System Management manager.
Andrea Williamson, Auckland System Management manager. Photo credit: Newshub

And the list of things that need to be maintained is huge as well, requiring up to 50 closures across the network each week.

"Obviously with lots and lots of cars you get lots and lots of issues," Williamson says.

"We've got crash damage, which can be barriers, can be pavement surface, can be bridges.

"We've also got renewals, which is basically the pavement lasts for so long and then it needs to be resurfaced. And the same with streetlights, the bulbs go out and you need to replace the bulbs."

Much of this can only be done when traffic volumes are lighter, detour routes are quieter and ASM can actually close lanes to keep the work crews safe - generally at night between 9pm and 5am.

"When we do maintenance activities we need to close the motorway generally and we can't do that during the day because there are too many cars on the road and we don't want to disrupt people's days," Williamson says.

The motorway on-ramp is closed off.
The motorway on-ramp is closed off. Photo credit: Newshub

Out on the North Shore, the closure is moving into full swing with ASM night operations manager Herb Brown in charge.

"There is a lot of the work that we need to be doing like barriers just for the safety of the public and for traffic itself," he says.

"There's also a bit of lighting work in there and just a little bit of maintenance work on the bridge structures and that inside the closure."

Herb Brown - the man in charge.
Herb Brown - the man in charge. Photo credit: Newshub

The onramps and main stretch of motorway are closed off with cones and detour routes signposted before it's safe for the crews to move out onto the motorway and start fixing things.

A car heading north has smashed into the safety barrier with such force it's knocked over the wooden posts and forced the metal guardrail until the wire.

This needs to be replaced to keep this section safe. First, workers unbolt the damaged section then a tractor is used to pull the metal barrier off. The wooden posts will need to be pulled out then driven back in.

Workers use a tractor to pull the damaged metal barrier off the posts.
Workers use a tractor to pull the damaged metal barrier off the posts. Photo credit: Newshub

In the middle of the closure a digger starts excavating a trench to lay a new cable, while down the other end of the closure, a team is replacing an exit sign.

The workers race to get all the work done and remove the cones and signs before the morning traffic picks up again.

"It's really important when we do a full closure that we don't go overtime in the morning so 5am is a sweet spot for getting off," Williamson says.

"We see a sharp rise in vehicle numbers from between 5 and 6am and then from 6am onwards it goes up and up and up and so getting off the motorway by 5am… means that it's safe for our crews to get off and go home to bed and it's safe for the most motorists to get onto the motorway."

The digger gets in action and starts digging the trench.
The digger gets in action and starts digging the trench. Photo credit: Newshub

Brown acknowledges that the closures and detours can be frustrating for motorists who want to use the motorway before 5am.

"Yes, we do still encounter frustration. There are still people that do work on nights, they still need to use the network," he says.

"But then at the end of the day we are here for the public, just to make the network safe for them."

Workers race to finish before the 5am deadline.
Workers race to finish before the 5am deadline. Photo credit: Newshub

And Williamson says it's critical that the work continues to fix potholes, cut back trees and replace crash barriers.

"The maintenance will last forever as long as we've got things that will break. We've got to keep changing bulbs, we've got to keep surfacing pavements, we've got to keep repairing barriers and we've got to keep making sure bridges stand up," she says.

"I think it's really important for the public to understand that what we do is not only to keep our crew safe but to keep them safe as well. So the cones are there for a reason.

"There is always something happening and there is always something going on within the closure - you might not see it, it might not be obvious, but there's always a reason for the closure."