Traffic 'memory' and works cause delay

Whangarei motorists finding their morning commute a little slower than usual are not alone, with three main arterial routes into Whangarei affected by roadworks.

Travellers from Whangarei Heads were among the worst affected, with resident Colleen Glenda reporting queues along Whangarei Heads Rd of up to 30 minutes just to reach Onerahi, then another 30 minutes into the CBD - about 6 kilometres of crawling traffic.

Across town major works had started on Western Hills Drive near Kensington and were also under way at the intersection of Kensington Ave and Kamo Rd, with diversions to be in place from this week.

Delays from Onerahi and Whangarei Heads were due to the installation of a slip-lane at the linking Dave Culham and Riverside drives, expected to alleviate congestion in the long run.

Sarra Vette lived on Old Onerahi Rd and said it took 20 to 30 minutes to crawl along Riverside Drive into town. Many cars were using her road as a detour to avoid traffic on Onerahi hill.

"I can't imagine how frustrating it must be coming from further back," she said.

"It's ridiculous how many cars are now coming down our road trying to skip the traffic on the hill! Can those doing it please be extra careful? Not everyone drives at a slow enough speed and there are lots of kids walking that road," she said.

Onerahi's Ben Haselden said people complaining about delays should "get over it".

"I got an extra 25 minutes sitting in traffic from Onerahi to practise my opera skills. It's already a great day," he said.

The $350,000 slip-lane would allow Port Rd-bound traffic to turn left over Te Matau O Pohe bridge, parallel to the pre-existing "straight through" lane.

Work had begun simultaneously on a walking and cycleway along Riverside Drive.

Cars slowing down to look at the work site compounded delays, said Whangarei District Council senior roading engineer Nick Marshall.

"[Another] major issue is that drivers on Riverside Drive are slowing and stopping to allow side traffic in. Because the inbound lane - morning traffic - is near saturation for the 30-minute peak, traffic flow can become unstable," he said.

"It causes what is known as a 'memory' in the traffic when a brief delay in one place can cause a long delay several kilometres back in the traffic even several minutes later."

The slip-lane would be finished by mid-March. The traffic management configuration would be in place for about two more weeks, then lane closures would be re-arranged for final pavement works.

Traffic appeared to be flowing well on Western Hills Drive, where the New Zealand Transport Agency was installing a roundabout at the intersection of Kensington Ave, with a dedicated northbound lane so vehicles could travel through without stopping. This was part of a suite of six projects by NZTA along Whangarei's SH1, worth $37 million.

WDC was responsible for works at the other end of Kensington Ave, which would complete the four-laning of Nixon St and improve the intersection at Kamo/Kensington and Nixon.