Traffic signals for ramps

Transit New Zealand is set to introduce ramp signals on Auckland's motorway network, in what could prove to be a controversial scheme to fight traffic congestion.

The first ramp signals will begin operating on the Southern Motorway at Papakura in October, followed by more at the Central Motorway Junction later in the year.

Transit New Zealand regional manager Peter Spies said ramp signals would help improve traffic flow on the motorway during peak periods by managing the rate at which vehicles merge from on-ramps on to the motorway.

However, a "ramp-metering" trial which was run on Mangere Bridge in 2004 for nine months, met mixed success.

"The result will be more predictable and reliable journey times and safer merging," he said.

The work will cost $27 million.

The ramp signals will be installed at all 31 on-ramps on the Southern Motorway, from Curran St in the north, to Papakura in the south.