Auckland's Waterview Tunnel has cut travel demand on State Highway 1 in the city by about 7 per cent, officials say.
There has been a corresponding increase on SH20 and SH16 and the redistribution "is resulting in a more efficient motorway system with around 8500 fewer hours each day of total travel time on the motorways alone", Transport Minister Simon Bridges said.
"Around 60,000 vehicles are using the Waterview Connection each day, with more than 2 million vehicles now having travelled through the twin tunnels between the suburbs of Owairaka and Waterview," Bridges said.
Bridges said average travel times between Papakura and the city in the morning peak have been "slashed".
"Journeys that used to take up to 70 minutes [are] now consistently taking 56 minutes. There are similar benefits in the evening peak. It used to take up to 55 minutes from the CBD to Papakura, while it's now consistently taking an average of 48 minutes," Bridges said.
The Waterview Tunnel is also benefiting those travelling between the city and the airport, he said.
"Prior to the Waterview Connection, journeys from the Airport to the CBD in the afternoon peak would take an average 44 minutes via Manukau Rd and Gillies Ave. Now, via the Waterview Tunnel, they take 27 minutes and via the Manukau/Gillies route they have also dropped to 34 minutes," Bridges said.