KEY POINTS:
I would like to know why Transit insists on spending millions of dollars setting up motorway onramp lights, widening the Newmarket flyover to try to speed up congestion and traffic on the motorway. All the while there is a deliberate choke in the system (at Mt Wellington) with the sole purpose of slowing down traffic. Surely the solution is to remove this deliberate brake? Signed, a reader whose name and address have been mislaid.
As advised, sir, this question was sent to Transit for their response. They say, and I quote, that "ramp signals are an important part of managing Auckland's motorways to reduce congestion by keeping traffic moving safely, and more consistently. To achieve this, the signals manage the flow of traffic onto the motorway during peak periods. At all other times they are turned off.
"Ramp signals run on a finely tuned system which can adjust each light phase, depending on traffic flow at each onramp. The signals are not intended to slow down traffic but rather to give a more equitable balance between the vehicles on the motorway and those on the onramp entering the motorway. By providing this balance, ramp signals ensure more predictable travel times, safer merging and more consistent speeds on the motorway. The congestion experienced on the motorway is not caused by ramp signals, but rather lessened by them."
And, as previously explained in at least three Get Moving columns, the two laning causing the brake at the Mt Wellington is indeed deliberate. The traffic is forced to slow down, thereby allowing traffic from the Southeastern Highway to merge on to the Southern Motorway.
What is happening around the motorway junction at Manukau? There have been serious earthworks there for several months, but their purpose has me puzzled. Is there any plan to aid traffic flows to the airport from the Southern Motorway? Alan Pike, Auckland.
The earthworks at the Redoubt Rd interchange are the beginning of construction of a flyover for the State Highway 20 Manukau Extension project. The project is to build a link from the Southern Motorway south of Manukau City centre to the Puhinui interchange on SH20.
The link will mean southbound traffic on the Southern will have direct access to the airport via SH20. When the job is finished, in 2010, traffic from SH20 will be able to join the Southern Motorway heading both north and south. Hopefully that will relieve the local roads in Manukau City, as well as giving more reliable trip times to and from the airport.
