Before SH1 Newlands became the smooth highway it is today it was a dangerous intersection. The Newlands intersection at the top of the Ngauranga Gorge was a notorious bottleneck. This was especially true in the 1990s. Before the Newlands Interchange was built it was the last traffic light controlled intersection on SH1 north of Wellington. Imagine the traffic jams. Queues stretched for miles. Southbound traffic backed up past the Johnsonville offramp. Northbound queues extended to the Ngauranga intersection.
SH1 Newlands was more than just a traffic problem. It was a legacy of the 1930s. Back then the Gorge road was upgraded as part of the Centennial Highway project. The project extended to Johnsonville. It wasn’t until much later that the highway continued beyond Plimmerton. This area of SH1 Newlands had a 100 km/h speed limit. A traffic light controlled intersection at that speed was a recipe for disaster. The situation was made worse by trucks from nearby quarries and industrial sites. These trucks had to cross into the fast lane to turn into Newlands.
Accidents were frequent. The intersection saw 28 injury accidents between 1991 and 1996. These ranged from minor fender benders to serious red-light collisions. The efficiency of this vital stretch of highway was seriously compromised. By the time the Newlands Interchange project began two similar intersections in Porirua had already been replaced.
The Newlands Interchange project was approved in 1993. Construction however didn’t start until 1996. It opened in March 1998. The delay wasn’t due to lack of funds. The project had a Benefit Cost Ratio of over 6. This meant $70 million in savings over 25 years. The savings were from reduced travel time and vehicle operating costs. Another $12 million was saved from accident reduction.
Delays were caused by planning appeals. Local residents worried about construction. The Rainforest Action Group also opposed the project. The project was initially budgeted at $9 million. The final cost was $16.3 million. Today SH1 Newlands is a vital artery. It smoothly connects Wellington with its northern suburbs and beyond. The Newlands Interchange solved the old intersection’s problems. It improved traffic flow and safety for all. The smooth flow of traffic today is a testament to this project. It’s a quiet tribute to overcoming challenges and building a better future.