Geoff Dangerfield: Harbour bridge walk too popular to permit

When the Auckland Harbour Bridge opened in 1959, 11,205 vehicles crossed it each day. In those pre-decimal times, people were tolled two shillings and sixpence (25c) to drive cars across the bridge.

(That 25c in 1959 is worth around $4.70 today - cars are tolled $2 on the Northern Gateway Toll Road.)

Fifty years later, the bridge tolls have long gone, and that first trickle of vehicles has become a torrent. The daily traffic count this year so far averages 154,000.

The bridge helped to open up development, particularly on the North Shore, allowing Auckland's population to mushroom in 50 years.

In May, 1959, it was estimated about 100,000 walked over the bridge before it was opened to traffic.

When the New Zealand Transport Agency last year began investigating ways to celebrate the 50th anniversary, a survey indicated as many as 318,000 people - about one-third of Auckland's population - would want to do the same again this month.

These are the numbers we had to plan for and it was these numbers that ultimately led to a decision by the Transport Agency board not to include a walkover as part of this year's celebrations.

The decision was made reluctantly after a thorough investigation.

To allow 300,000 or more people to safely cross the bridge would take at least six-and-a-half hours. This would happen as we approach mid-winter, with the available hours of daylight short to accommodate a crowd of that size and then reopen the bridge.

People would have to cross the outer lanes of the bridge to use the four lanes on the central, or truss, section.

The clip-ons are not a viable alternative. They are more flexible than the truss and large numbers of people walking on them would cause significant movement and challenge our ability to ensure their safety.

Two of the clip-on lanes would also have to be kept open for emergency vehicles and public transport.

Another serious constraint was a "pinch point" on the south side of the bridge.

To get 300,000-plus people over the bridge in time would mean 35,000 crossing every hour. However, the narrowness of the Fanshawe St on-ramp means only 23,500 could walk through every hour with comfort and safety.

To solve this challenge, we looked at restricting the walk to one direction.

The idea had to be dropped after the discovery that there were not enough buses available to bring people back across the bridge.

The Transport Agency considered restricting the number of people to 120,000 as a possible and manageable solution. It was eventually discounted because of the cost involved in having to register and identify walkers, provide security and public transport for them, and the unavailability of any suitable location near the bridge to register large numbers of people.

The total cost of planning and managing a bridge walk was estimated at between $1 million and $1.25 million.

The Transport Agency set aside a budget of about $500,000 as its share.

Regional partners were consulted, and although they were keen for the walk to happen and were willing to provide logistical support, none had money available to contribute to the cost. The agency also had to be mindful of the current economic climate and the need to be prudent with how we spend public money.

While the Auckland Harbour Bridge is a motorway environment, the agency recognises its importance in the lives of Aucklanders and its status as a regional and national icon.

In November each year, the two western clip-on lanes are used as part of the course for the Auckland Marathon.

The closure starts at 6am and the lanes reopen three hours later before the build-up of weekend traffic.

Marathon organisers are responsible for the expenses associated with the closure - providing security, race marshals and emergency services on the bridge, adequate identification for the athletes, and a traffic management plan.

We have told the Auckland Regional Council we would consider its request to allow cyclists and walkers on to the bridge next summer if the council can provide safety and security support similar to that provided for the marathon.

From day one, the Auckland Harbour Bridge has been a key contributor to the development of the region. Its significance as the city's critical transport link shows no sign of diminishing in the future.

That importance becomes even more apparent when you look at other cities. In Sydney, people were allowed to walk their harbour bridge. The difference is that Sydneysiders have alternative transport links: their harbour bridge includes rail, there's a road tunnel under the harbour and the Anzac Bridge as well.

Our harbour bridge is the region's only direct north-south link. Closing it for hours would create severe and widespread congestion that would take hours to clear and leave road users with long and slow diversions.

The Transport Agency will be marking the anniversary of the bridge in a more modest way.

We believe the best way to commemorate this milestone is to ensure that the bridge keeps playing its part in our daily lives.

* Geoff Dangerfield is chief executive of the Transport Agency.