The northbound lanes of Auckland's Southern Motorway have reopened on Sunday afternoon after being closed for construction work.
State Highway 1 was closed between Market Rd and Gillies Ave at 5pm on Saturday for lanes to be switched to the new Newmarket Viaduct.
Monday is Auckland Anniversary Day and major traffic delays had been expected because of the road closure.
However, drivers heeded warnings to stay away, NZ Transport Authority's acting Auckland and Northland state highways manager Steve Mutton says.
"Traffic flowed pretty smoothly throughout the day with minimal delays. We were aiming to reduce traffic by about 50 per cent and its looks like it was as high as 75-80 per cent - that is an amazing result and again demonstrates the high levels of support we get from drivers."
The viaduct had opened to traffic 17 hours ahead of schedule, Mr Mutton said.
"Support from Auckland's drivers during the closure was fantastic, and was a significant factor in allowing the NZTA and its partners on the Newmarket Viaduct replacement project to complete their work hours earlier than planned."
NZN