KEY POINTS:
Motorists willing to pay $2 to use New Zealand's first "freeflow" toll road, opening next weekend, will be treated to spectacular scenery rivalling the winding coastal route it will supplant along State Highway One.
Three elegant viaducts along the 7.5km route of the $365 million Northern Gateway road
between Orewa and Puhoi will sweep motorists past regenerating native bush on the hills above Hibiscus Coast.
They will be treated to fleeting glimpses of the coast above stands of nikau palms, from a viaduct reaching 537m across the Waiwera River, and from another of half that length over the northern arm of the Otanerua Stream flowing into Hatfields Beach.
The third viaduct - over the Nukumea Stream towards the Orewa end of the road - was added as a last-minute environmental enhancement to the project, to limit disruption to the movements of rare semi-flightless fernbirds and New Zealand's largest native fish, the kokopu.
Also added was a pair of 385m tunnels poking through bushclad Johnstone's Hill. Digging the tunnels at an extra cost of $35 million enabled planners to avoid making a 60m cut through the hill and severing an important wildlife corridor joining Wenderholm Regional Park to its hinterland.
Even so, about four million cubic metres of earth and rock was cut through the route, more than a quarter blasted out of a saddle under the 157m summit of Chin Hill south of the Waiwera River.
Another striking feature of the motorway is a banana-shaped bridge built to carry local traffic high above it, along an extension of Hillcrest Rd, just north of the Nukumea Viaduct.
The bridge has no centre pier but instead two sets of legs on each side of the road, coloured red after the pukeko, the official bird of the project.
It was built "top-down", meaning the bridge was built before the ground beneath it was dug out to motorway level, 25m below.
The Transport Agency hopes logistical challenges posed by the introduction of its $28 million electronic toll collection system will not detract from motorists' enjoyment of the natural grandeur of the new route, which it has revegetated with 750,000 native plants to supplement those untouched by the construction work.
A www.tollroad.govt.nz animation says electronic payment methods, on the internet or by phone and linked to the national vehicle registration centre, will enable motorists "to just drive and let us worry about the rest".
"With no toll booths, meaning there is no place to stop and pay, travel on the toll road is faster with no interruptions - no hunting for loose change," the animation promises.
Payment machines will be available for those who prefer to deal in cash, but will be kept separate from the toll road, at the BP Connect service centre for northbound traffic and on State Highway One south of Puhoi for motorists heading to Auckland.
Signs will offer motorists the opportunity to turn off the new main road to the old Hibiscus Coast Highway if they want a free ride.
Once northbound motorists pass under banks of cameras mounted on 6m gantries about 1km beyond the new road's Orewa interchange, they will receive two signposted reminders that enjoying the different scenery and a time saving of six to nine minutes off the coastal route comes at a price.
Also in keeping with the natural values of the areas, which environmentalists spent years battling for, was a decision to extend the tunnel portals out from Johnstone's Hill to provide a battered slope above them for revegetation. The agency's project manager Brett Gliddon said a vertical concrete face initially proposed would have been ugly so the project's construction partners decided to vary the plan, at what turned out to be no extra cost.
Even the interiors of the tunnels will be tuned into nature, by automatic control systems that will adjust the brightness of lighting to conditions outside, to make it easier for motorists' eyes to adjust when they emerge.
Each tunnel has been made large enough to carry two lanes of traffic, but there will be only one northbound lane until a dual carriageway is extended past Puhoi on SH1.
TAKING A TOLL
* Cost: cars and motorcycles - $2, heavy vehicles (over 3.5 tonnes) - $4.
* No extra charge for caravans or trailers.
* Overhead cameras measure vehicles to determine category, tariff payable and type of payment arrangement.
* Regular users can set up an account at www.tollroad.govt.nz or by calling 0800 402 020.
* One-off payments - for up to 10 trips a month - can be made through www.tollroad.govt.nz or by calling (0800) 402-020.
* Cash payments: Northbound traffic - BP service station at Dairy Flat. Southbound - payment point on State Highway 1, about 1km before the Waiwera exit.
* If you do not prepay your toll, you have three days to pay before a $40 infringement notice is sent.