Strengthening project

As one of New Zealand’s critical transport links, ongoing maintenance keeps the Auckland Harbour Bridge in good condition for the 172,000 cars that cross it daily.

The 60 year old bridge is no stranger to maintenance, with annual, six and three month inspections and daily monitoring, painting and other checks taking place.

The clip-ons are closed while the welding takes place.

A recent project has seen the box girders, also known as the clip-ons, strengthened to their maximum capacity. Approximately 900 tonnes of steel has been bolted and welded onto the clip-ons to extend the life of the bridge.

A brief history of the project:

  • April 2008 - August 2008: work starts to improve access, ventilation and lighting and provide power for construction workers
  • August 2009: works starts to strengthen the northbound clip-on
  • Mid-June 2009: trucks were allowed back onto lane 2 of the clip-on as strengthening work progresses
  • August 2009: strengthening of the northbound clip-on is completed and workers start on the southbound clip-on
  • November 2010: estimated completion of both clip-ons
  • December 2010: truck restrictions lifted.

Minimising disruption to motorists:

  • Working around the clock
  • Extensive traffic management planning to minimise disruption
  • Keeping motorists and workers safe.

Freight on the bridge

All bridge users, whether they are commuters, car and truck drivers, the utility companies or tourists taking the walk with Auckland Bridge Climb, benefit from our ongoing commitment to keeping the structure in good condition.

Bungy jumping on the bridge

Rather than looking at the bridge as just a concrete and steel structure, its operating plan sees it as a whole corridor, managed carefully to meet all users' needs now and into the future.

The most important route for transporting goods; and a vital economic link between north and south; each year approximately 5 million tonnes of freight are transported over the bridge.

The NZ Transport Agency works closely with the transport industry on 5 E’s - education, encouragement, enforcement, engineering and evaluation to manage live loading (the maximum traffic load a structure can support) on the bridge. 

This partnership also helps stop over dimension and over weight vehicles from causing excessive wear and tear and safety risks, especially in the narrower lane 3 when the moveable lane barrier machine is in operation.

As long as the live traffic load is carefully managed, the bridge can continue to be used indefinitely. The bridge works hardest between 5am and 6am, which is the busiest time of the day for freight.

A ‘Weigh In Motion’ facility enables vehicles to be weighed as they drive over the bridge, and captures the number plates of overweight or over dimension vehicles. The Transport Agency and the transport industry collaborate on stopping this practice to benefit everyone.

Moveable lane barrier

In February 2008, a new 2.2km moveable lane barrier was installed on Auckland Harbour Bridge.

Complete with two new barrier machines, the system operates at twice the speed of the old machine, which was installed back in 1990.

Auckland Harbour Bridge.

The moveable lane barrier increases the number of lanes available in the peak times and directions, maximising capacity on the bridge.

Facts and figures

  • The first moveable barrier installed in 1990 was the first permanent moveable barrier system to operate on a major bridge anywhere in the world
  • The new machines operate at twice the speed of the old machines, taking 20 minutes instead of 40 minutes, so motorists benefit from a much smoother transition from one lane configuration to another
  • A $6.6 million contract was awarded to U.S. based company Barrier Systems to install and project manage the 2008 barrier system
  • The machines were manufactured at Barrier Systems Inc in Rio Vista, California
  • The barrier was manufactured in New Zealand at Humes factory in Hamilton
  • Moveable lane barriers improve traffic flow by increasing the number of available lanes in the peak direction twice a day and maximising capacity on the bridge during peak times through the ‘tidal flow’ configuration
  • In morning peaks the barrier is moved from a central position into a 5/3 (five lanes south and three lanes north) configuration
  • In evening peaks, the configuration switches to five lanes north and three lanes south
  • Outside of peak periods the barrier is moved to the centre of the bridge to create four lanes in each direction
  • The vehicles are stored in the garages (known as the ‘elephant houses’) at the north and south end of the Harbour Bridge.


Each year bridge workers postpone their Christmas holidays to resurface the clip-on lanes on the Auckland Harbour Bridge. The resurfacing first took place over the Christmas and New Year of 1995 and 1996 and now continues annually, always during holidays to minimise the inconvenience to Auckland commuters.

Northbound traffic on the Auckland Harbour Bridge.

Six other traffic lanes on the harbour bridge will remain open during this time – three in each direction.

Significant delays are expected, so please avoid the area if you can and follow the signposted detours in place. It’s best to allow extra time for your journey, especially heading out of the central city.