Large toll rings enveloping the Auckland isthmus could knock traffic congestion harder than other road-charging schemes, but officials admit they may be too complex to win ready public support.

Consultants have warned the Ministry of Transport in a $2.3 million study of five possible schemes aimed at pricing cars off congested Auckland roads of a need to keep charges transparent and easy to understand.

Any complexity making a scheme hard to understand risked seeming a "sneaky" way to raise revenue, the ministry was told before putting the five options up for public submissions closing on Friday.

Although officials endorse a need for hefty spending on public transport to soften social impacts of road charges, they must conquer the suspicions of motorists who fear these may become "just another tax" for a Government slush fund.

Two of the five possible schemes would involve cordon tolls, in which all or large sectors of the Auckland isthmus would be ringed by electronic scanners and cameras, to charge passing motorists up to $6 a day in the week-day morning traffic peak.

One scheme would have a single cordon wrapped around the entire isthmus, from New Lynn to the Tamaki River.

The other, a double cordon with inner and outer rings covering a smaller but still large area of the isthmus, would have separate charges for entering each circle.


Single cordon:

This would be the largest scheme, but the easiest of the five to implement, as water boundaries mean only 15 charging points would be needed on bridges and comparatively narrow land approaches.

Motorists from the west and south would be charged just half of a $6 fee applying to traffic arriving across the harbour bridge, as the ministry believes there are fewer areas of social deprivation in North Shore and better public transport through the main motorway corridor.

Double cordon:

This would involve two charging rings, the outer of which would have much the same boundary as the single cordon, except on the western side.

There would be 50 charging points.

The western boundary would extend only to Mt Roskill and the State Highway 20 corridor being developed as Auckland's western ring route. The inner boundary would be identical to another option, the so-called area charging scheme, stretching from Westmere to Hobson Bay via an east-west route including Greenlane Rd and Balmoral Rd.


Electronic forms of cordon or ring tolling are well established in countries such as Singapore and Norway and Sweden's capital, Stockholm, has a six-month trial in progress on an isthmus similar in shape although substantially smaller than Auckland's.


Single cordon:

Very effective at reducing congestion as motorists heading between different sectors of the Auckland region cannot skirt the cordon. Produces the most impressive reduction in commuting times to key economic centres, by an average of 22 per cent.

But this scheme would separate many workers in socially deprived areas, particularly in west Auckland, from jobs in the industrial south.

Waitakere City Council regards the scheme as particularly inequitable as those living and working within the cordon would not have to pay road charges, despite enjoying most of the benefits of reduced congestion.

Would cost the average affected household $956 a year.

Double cordon:

This has the most impressive anti-congestion benefits of all the schemes. By 2016 it is expected to reduce traffic jams by 40 per cent in the morning peak, and increase average speed over the regional roading network by 4.5km/h to 44km/h.

Would cost the average affected household $1014 a year.


Single cordon:

Chances of its being introduced appear remote. Operating costs will claim half the scheme's gross annual revenue of $111 million, and officials do not believe it will be nearly lucrative enough to cover required mitigation measures such as adequate cross-town bus services. To do that, it would end up $92 million in the red over 20 years.

Double cordon:

Despite its de-congestion benefits, difficulties in mitigating social impacts put it at a disadvantage to the area scheme, which has been favoured behind the scenes by Government ministers.


Vedran Jovic thinks it unfair he may have to pay twice as much to drive over the harbour bridge from North Shore City as motorists arriving in Auckland from other directions.

The 18-year-old University of Auckland science student shares a car with his brother each day from Glenfield, because they park for free in the Domain, which he says makes it cheaper than an $8 return bus fare each.

Mr Jovic, who works part-time and will finish a chemistry degree with a student loan to repay, believes the car will remain more affordable even if a $6 cordon toll is put on the bridge, as suggested in two out of five options under Government consideration.

He said transport authorities must reduce bus fares if they are serious about beating congestion, and he resents their assumption that North Shore residents can afford to pay more than commuters from western or southern suburbs.

"We are not really well off on this side of the motorway. I have lived in West Auckland and there's not much difference."