Up to 365 homes face the bulldozer under a $1.4 billion rethink of the western ring route bypass of central Auckland.
The Transport Agency yesterday announced a combined "surface-tunnel" option to fill the final gap in the 48km route - a largely undesignated tract of residential and park land between Mt Roskill and the Northwestern Motorway at Waterview.
It will add about 200 homes to the 160 that would have had to be cleared from each end of twin tunnels below most of the 4.5km route.
But Transport Minister Steven Joyce said he believed it struck "a fair balance between the needs of the local community and those of the country and the economy".
The Automobile Association and Road Transport Forum welcomed the plan as a boost to the economy, and the Contractors' Federation said it would be built with far more involvement from local industry than the twin tunnels, for which a boring machine would have had to be imported for about $50 million.
Forum chief executive Tony Friedlander felt the revised Waterview Connection was the most sensible and affordable choice.
Mr Friedlander said the completion of the ring route would have a marked economic impact on Auckland, by reducing congestion and the amount of time Aucklanders spent on the road.
The AA said a report in 2006 estimated the benefit of the completed ring route at $840 million a year.
About $390 million of this would come from economic benefits - travel for work and hospital costs - and $14.2 million from non-economic - educational and recreational travel. The flow-on effects would be worth $431 million.
The latest proposal has emerged after 10 years of community consultations and the Government's dismissal this week of the twin-tunnels proposal, which it inherited from Labour.
The Treasury had costed the twin-tunnels at up to $2.77 billion.
The plan will still provide about 1.8km of tunnels, of which 700m will be dug underground and the rest will be a covered trench beneath Great North Rd to Waterview.
Oakley Creek - a beauty spot that had been threatened by earlier motorway proposals - is expected to be largely unscathed.
An initial section of about 2.2km from the end of the Mt Roskill motorway extension - which is due to open in stages from tomorrow - will be above ground and largely through a green belt long designated for rail.
The new motorway - similar to the Roskill extension of two lanes in each direction with enough room for an extra lane if needed - will still leave space for trains.
The first tunnel will stretch beneath New North Rd and Avondale Heights.
It will end south of the Blockhouse Bay Rd-Great North Rd intersection, where the motorway will run above ground for about 150m, continuing along a "cut and cover" trench to the Northwestern.
Transport Agency chief executive Geoff Dangerfield said it would "sit under" Great North Rd, along which traffic will have to be diverted in short stages as construction of the motorway inches towards an interchange at the bottom of the Waterview straight.
Although the motorway will destroy more than twice as many homes as the twin-tunnels proposal, other cheaper options which the agency discarded would have bulldozed through even more properties, and compromised Oakley Creek with bridges over it.
The only major impact on the creek will be flyovers near its mouth, at Waterview, similar to what was proposed for the twin tunnels.
The cheapest option would have cost $342 million less, but agency chairman Brian Roche said the extra community and environmental disruption would have been "significantly disproportionate" to the saving.
Auckland City Mayor John Banks agreed that Oakley Creek was a "historical environment that is critical to the future of Auckland".
He saw the new plan as a sound and sensible compromise, but vowed to ensure homeowners were fairly compensated.