Ask Phoebe: Unravelling the mystery of bridge building

A number of agencies use the building near the harbour bridge, including the serious crash unit. Photo / Paul Estcourt

I drive across the Auckland Harbour Bridge daily. At the northern end there is a big administration building. Who works in there and what do they do? If they are harbour bridge control people, why does it sometimes take so long to clear breakdowns and crashes? Do they have screens to monitor traffic flow? Jenny Myers, Takapuna.

This building is the former home of the Auckland Harbour Bridge Authority, hence the logo on the front door handles.

It now houses some police sections, particularly the serious crash unit and the motorway patrols. But a good part of the building is used by the Traffic Management Unit (TMU), a partnership between the NZ Transport Agency and local councils.

The TMU monitors 250 cameras on the region's roading network. Half of these keep an eye on the motorways, and the rest are located at signalised intersections within the region.

As well as monitoring traffic flow, and adjusting traffic lights and ramp metering lights as required, the cameras are also used to locate and confirm traffic incidents. For example, if the police receive a *555 call, they call the TMU to confirm the position of the incident, and what the situation is there. The police then decide what response is required.

Responses generally take less than 10 minutes, but resolution can take much longer, especially within the tight confines of the harbour bridge. Getting emergency vehicles to an accident on the bridge can be difficult in peak hours, as is getting a tow truck there if required, and cleaning up debris.

It is not possible to move the barriers on the bridge when it is loaded up with traffic, obviously, but other solutions such as opening up bus lanes to general traffic have been suggested.

The TMU also monitors individual intersections within the city, and can alter light phasing when it's needed. They can set up what's called a 'green wave' down an arterial road such as Nelson St, so that if you hit the first set of lights on green, you will (or should) get green lights all the way down the street.

Changes to the phasing of the lights at Queen St intersections have also been made by TMU. Because there are more pedestrians than vehicles, the pedestrians get extra crossing times in between the lights for east-west traffic and north-south traffic.

And when you ring your local council to advise or complain about phasing at a particular set of lights, they pass the message on to the TMU who send out contractors to fix the problem.

Can you please tell me if there are special laws covering parking in a railway station carpark? I park every morning at 6.30 in the town-side carpark at Papakura railway station to catch my train to the city. For some time now I have seen staff from nearby Countdown supermarket parking there too, thus filling the carpark early. This seems unfair as it was designed for commuters, and Countdown has a huge carpark of its own. Jill Wheeler, Drury.

Papakura District Council's Park and Ride facility provides car parking spaces on both sides of the main trunk line at the railway station.

The carparks were put there by the council to encourage people to use public transport, and are monitored by security staff, so that people have a safe and convenient place to park while they use the train into the city. They were never intended to provide parking for the staff of local businesses and the council is encouraging businesses in the town centre to use other free all-day parking. There are two buildings offering hundreds of free all-day carparks within three minutes walk of Countdown, one of which has all-day security supervision.

However, the Park and Ride carparks are free public carparks and open to all of the public, not just to those who use it to travel by rail to the city.

A spokesman for Progressive Enterprises, which runs Countdown, says there isn't an allocation for staff parking at Papakura Countdown, as the parking is limited to 221 cars. The carpark is also shared with another local business.

But the spokesman says that Progressive is in contact with the local authorities to find alternative parking.

Be aware that Railway St West is in the throes of a major upgrade as part of the changes to the Papakura town centre. Access to businesses in the street remains open, but some parking may be moved or temporarily unavailable.