It is WA's biggest and most expensive road project but it is only in recent weeks that its sheer scale has become apparent.
The $1 billion Gateway WA project, due to be completed a few months ahead of schedule in late 2016, is designed to ease the daily gridlock that chokes Perth Airport, Kewdale and Welshpool.
Its centrepiece is the three- level interchange at Tonkin Highway and Leach Highway, the main gateway from the Perth International Airport into the city.
An artist's impression shows three levels of roads that will be 13.9m from its lowest to its highest point.
This posed a number of engineering challenges - the interchange couldn't be too high because it is so close to the Perth Airport runway and it couldn't be too low because of the high groundwater levels.
So, the lowest roads have been sunk up to 4m into waterproofed concrete "baths". This means the groundwater can be held at bay and the overhaul height of the interchange will not affect planes landing or taking off.
But Gateway WA is far more than just this one interchange. The project involves widening Tonkin Highway to six lanes between Great Eastern and Roe highways, upgrading Leach Highway to "expressway" standard between Orrong Road and the airport and building new bridges and interchanges at Tonkin Highway/Leach Highway, Tonkin Highway/Horrie Miller Drive, Leach Highway/Abernethy Road and Tonkin Highway/Dunreath Drive.
The Weekend West joined Transport Minister Dean Nalder on a tour of the site yesterday and it was clear that the two years of planning had paid dividends in ensuring that disruptions to surrounding traffic was kept to a minimum.
With about 800 people working on the project on any one day, project management is also an important part of the operation.
The project is so big, it has been separated into three construction zones - north, south and west - each with their own project manager, design and construction team.
The alliance building the project consists of Leighton Contractors, Georgiou, GHD, AECOM and BG&E.