The New Zealand Transport Agency (NZTA) has proposed three transport scenarios to complement the Harbour Bridge in Auckland.
The bridge, which has connected Auckland's city centre to the North Shore for 60 years, is reaching capacity during peak hours.
"Outside peak traffic periods, [Auckland Harbour Bridge] daily traffic flow has increased by approximately 2 percent per year since 2008," a report says. "Daily flow sometimes exceeds 200,000 vehicles."
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Morning and afternoon traffic is ballooning as the city's population increases each year, and the NZTA is now considering three options to help ease the load.
In a Ministerial Briefing Note, the NZTA says it's considering three options.
- Build a tunnel for light rail
- Build a tunnel for both light rail and vehicles
- Don't do anything
A combination of light rail and road pricing would be the best option for reducing the heavy morning traffic on the Auckland Harbour Bridge, the report says.
"A light rail only crossing combined with road pricing delivers the best outcome for the city centre in terms of fewer cars entering the city centre during peak traffic times."
The proposed options will be considered by Transport Minister Phil Twyford and Associate Transport Minister Julie Anne Genter, who were given the report in September.
The report also noted how heavy vehicle restrictions for the Auckland Harbour Bridge could be added in the future to help it last longer. The NZTA has in the past considered a weight restriction of 35 tonnes.
"Forecasts indicate that restrictions for heavy vehicles on the [Auckland Harbour Bridge] may be required by approximately 2030," the report says.
There's a business case for introducing an alternative transport mode, the report adds. Currently around 31,000 people travel southbound over the bridge in the morning, with 58 percent of them travelling by bus.
It also says due to increased travel demand and the forecast traffic congestion, "demand for public transport is forecast to double in the AM and PM peak period by 2046".