The NZ Transport Agency is advising drivers that from next Monday, 30 May, there will be significant changes to Auckland's Southwestern Motorway (State Highway 20) and the Walmsley Road on ramp at Mangere Bridge.
The additional third southbound lane under the Walmsley Road on ramp will be opened early on Monday morning for traffic heading to Auckland International Airport and to Manukau. At the same time, safety improvements to the on ramp become operational and traffic using it will no longer be able to "weave" across the motorway to join SH20A for the airport. They will be prevented from doing so by a 900 metre-long barrier between the on ramp and the motorway that will direct all on ramp traffic to Manukau and beyond.
"The improvements around Walmsley Road will help provide safer and more reliable journey times for those heading to the airport and further south," says the NZTA's Project Services Manager, Tom Newson.
"The wider section of motorway will help ease congestion, particularly at peak times, and the on ramp barrier will improve safety and stop people from trying to cross high speed motorway lanes to go to the airport."
"Drivers need to be aware of the new layouts to the motorway and the on ramp and take extra care," Mr Newson adds.
People who normally use Walmsley Road to access the airport will be directed on to local roads.
The on ramp and the southbound lanes of the Southwestern Motorway from Walmsley Road to Kirkbride Road (SH20A) and Massey Road (SH20) will be closed from 9pm this Sunday (29 May) until 5am the next morning to allow contractors to complete the changes. Airport traffic will be diverted from Walmsley Road to McKenzie and Kirkbride Roads. Traffic for Manukau and further south will be diverted along Walmsley and Robertson Roads to Massey Road.
The closure will be weather dependent.
Although traffic should be light at that time of night, Mr Newson says people driving to the airport should allow more time for their journeys.
All northbound lanes of the motorway are not affected and will remain open.
Contractors say further overnight closures on the same section of motorway are planned for next week to complete the upgrade.
The improvements mark the end of construction around the Manukau Harbour Crossing project involving Fletcher Building, Beca, Higgins and the NZTA.