Plans for one of the country's most expensive transport projects - a $760 million extension of Auckland's motorway network to Warkworth - go under the microscope today.
A board of inquiry appointed for fast-tracking planning consideration of the 18.5km extension as the first half of a Road of National Significance will preside over 14 days of hearings.
The Government is promoting the extension over 12 viaducts and bridges from the Johnstones Hill traffic tunnels south of Puhoi to a new roundabout north of Warkworth, as a vital freight and tourism link with Northland.
Even so, many of the 14,000 vehicles a day expected to use the new road by 2026 will double back to Warkworth's often bottlenecked Hill St turnoff to eastern beaches.
That keeps critics such as Auckland Council infrastructure chairman Mike Lee calling it "the holiday highway" to the intense annoyance of Northland leaders and former Rodney mayor Penny Webster.
The Transport Agency expects the road to cut five to seven minutes off regular journeys, and up to 16 minutes for traffic heading to eastern beaches at holiday weekends, while recommending motorists be tolled.
There will only be one traffic interchange between Orewa and Warkworth, to be confined to just south-facing ramps at Puhoi, after residents protested against an earlier plan which would have denied them access.
Although part of a 38km route to Wellsford among the Government's seven Roads of National Significance, the Warkworth extension is earmarked for earlier planning approval while geotechnical difficulties further north - through the Dome Valley's motoring black spots - remain unresolved.
Not that the Warkworth leg will be any cakewalk. The Department of Conservation and Auckland Council are concerned about pollution and potential flooding from sedimentation of waterways feeding the Hauraki Gulf, from about eight million cubic metres of earthworks which the Transport Agency insists it will be able to contain.
Residents at the end of the Perry Rd valley south of Warkworth, including some of about 50 owners of properties needed for the project, are concerned about the road's incursion into kauri forest.
Labour and the Greens vow to scrap the project in favour of urban transport investment such as an early start on Auckland's $2.86 billion underground railway, if elected this year.
However the agency hopes to allay such concerns and win planning approval before September's general election. But it has yet to propose a start date for a five-year construction programme.