Five years and $1.4b later, the country's most ambitious roading project - the Waterview Connection - has opened.
The first vehicle to travel through the tunnel, which connects Auckland's Northwestern and Southwestern motorways, was clocked at 12:47am on Sunday morning.
CCTV footage showed the first cars to enter the northbound tunnel, travelling from Owairaka to Waterview, accompanied by three police vehicles.
Newshub observed lines of clogged traffic and lane closures from around 11pm on Saturday night from the Newton Rd exit ramp on the Northwestern Motorway, heading west.
The New Zealand Transport Agency has encouraged motorists to avoid rushing to drive through the tunnel in the first few days after opening, to ease traffic congestion and delays on roads in and around the connection.
Auckland Highway Manager Brett Gliddon said as with any new piece of infrastructure, there will be a settling in period while people adapt their journeys and get used to driving in such a long tunnel.
"When it first opens motorists should expect the tunnel to be very busy because we know many people are keen to experience driving it for the first time. The Waterview Connection will be a key part of the Auckland transport system for a long time now and there'll be plenty of opportunity for everyone to use it.
"We will be monitoring traffic flows carefully over the next few months and we're asking people to bear with us while everyone gets used to the new route and driving conditions. Everyone can play their part by planning their journeys before they set out."
The Waterview Connection is the final link in the Western Ring Route, one of the Government's Roads of National Significance to support growth and development.
Mr Gliddon said the connection "will change the way people and freight move around Auckland and the rest of the country, offering a true alternative route that bypasses the city centre".
The 48km Western Ring Route will create more transport options with bus lanes and walking and cycling connections, and create efficient links to and from Auckland Airport.
While it's not designed to remove peak time congestion altogether, Mr Gliddon said it will provide a better balance of traffic flows across the road network, including helping to remove cars from local roads.
It's opening has been long-delayed. Finance Minister Steven Joyce said in May it would be open "in the next couple of weeks".
Updates to Apple and Google Maps on Saturday said it would open overnight, but NZTA would not confirm the rumours.